Ultrasonic sensor system and related methods

Abstract

The invention relates to a method for operating a related ultrasonic sensor system (22) of an environmental sensor device of a vehicle and / or robot, in particular for parking assistance, and to the ultrasonic sensor system (22) itself. The ultrasonic sensor system (22) comprises an ultrasonic sensor (1). In the near distance of the ultrasonic sensor (1), it is no longer able to detect its distance to an object (11) using a first time length of a transmitted ultrasonic pulse train (10) without additional measures. If no object (11) is present in the near distance of the ultrasonic sensor (1), an ultrasonic main measurement (505) is performed using the first time length of the transmitted ultrasonic pulse train (10), and if an object (11) is present in the near distance, the presence of the object (11) in the near distance of the ultrasonic sensor (1) is detected. The method shortens the first time length of the transmitted ultrasonic pulse train (10) to a second time length of the transmitted ultrasonic pulse train (10), and detects the distance between the ultrasonic sensor (1) and the object (11) for the duration of the presence of the object (11) in the near distance of the ultrasonic sensor (1).

Description

Technical Field

[0001] This invention relates to an ultrasonic sensor system for detecting objects within close range of an ultrasonic sensor system, and to a related method for detecting objects within close range of an ultrasonic sensor by utilizing temperature and parameter compensation at the end of the oscillation process of the oscillating element of the ultrasonic transducer of the ultrasonic sensor. Background Technology

[0002] For autonomous driving, vehicles require what are known as driver assistance systems. Existing literature also refers to these as Advanced Driver Assistance Systems (ADAS). These ADAS systems require sensor data from sensors. These sensors provide the ADAS system with environmental data about the vehicle's surroundings. An important category of such environmental sensors is ultrasonic sensors in ultrasonic sensor systems. Such ultrasonic sensor systems typically include a control unit and multiple ultrasonic sensors. Typically, the control unit is connected to the ultrasonic sensors via one or more data buses. Older ultrasonic sensors used analog data buses and more or less included the output signal of a comparator within the ultrasonic sensor. Furthermore, more modern ultrasonic sensors include their own computer core, which controls the transmission of ultrasonic pulse trains and the reception of ultrasonic echo signals, performs communication with the control unit, and processes and compresses data as needed.

[0003] The following sections will illustrate the problem to be solved using the accompanying figures provided in this article.

[0004] Typically, an ultrasonic sensor 1, as defined in the literature presented herein, includes a computer core 2, a digital ultrasonic pulse train generator 3, and an analog ultrasonic emission stage 6.

[0005] Preferably, the computer core 2 controls the digital ultrasonic pulse train generator 3 of the ultrasonic sensor 1 via one or more control signals 4. Typically, the data link between the ultrasonic pulse train generator 3 of the ultrasonic sensor 1 and the computer core 2 has a return channel that allows the computer core 2 to check the status of the ultrasonic pulse train generator 3 of the ultrasonic sensor 1.

[0006] The digital ultrasonic pulse train generator 3 generates a digital ultrasonic transmission signal 5 under the excitation of the computer core 2.

[0007] The analog ultrasonic transmitter stage 6 typically converts the digital ultrasonic transmitter signal 5 into a drive signal 7. During the temporal transmission phase, while generating the ultrasonic pulse train 10 to be transmitted, the drive signal 7 supplies pulsed electrical energy to the piezoelectric oscillating element 8 of the connected ultrasonic transducer 9. Typically, the pulse frequency of the energy supplied to the oscillating element 8 is close to the resonant frequency of the oscillating element 8 of the ultrasonic transducer 9. As a result, during this transmission phase, the oscillating element 8 of the ultrasonic transducer 9 vibrates at the pulse frequency. The oscillating element 8 of the ultrasonic transducer 9 transmits its mechanical vibrations to the surrounding air, thereby causing the ultrasonic transducer 9 to emit the ultrasonic pulse train 10. The emitted ultrasonic pulse train 10 preferably comprises multiple pulses that follow each other at the pulse frequency. Therefore, a pulse in the context of this literature is a single compression or expansion wave of air. An ultrasonic pulse train in the context of this literature comprises at least one pulse. An ultrasonic pulse train in the context of this literature may comprise multiple temporally consecutive pulses. The number of temporally consecutive pulses in the emitted ultrasonic pulse train 10 can be large or small. The emitted ultrasonic pulse train 10 consists of pulses that follow each other at time pulse intervals, with each pulse corresponding to the instantaneous reciprocal of the instantaneous pulse frequency. Therefore, the emitted ultrasonic pulse train 10 emitted by the ultrasonic transducer 9 can be either a longer or shorter duration. The shorter duration ultrasonic pulse train 10 comprises several pulses, while the longer duration ultrasonic pulse train 10 comprises a larger number of pulses.

[0008] An object 11 near the vehicle will reflect the emitted ultrasonic pulse train 10 as a reflected ultrasonic pulse train 12.

[0009] After generating the transmitted ultrasonic pulse train 10, the ultrasonic sensor 1 enters a temporal oscillation phase. During this decay phase, because the oscillation amplitude of the piezoelectric oscillating element 8 of the ultrasonic sensor 1 is still too high at the start of the decay phase, the ultrasonic sensor 1 is typically unable to receive the reflected ultrasonic pulse train 12 for the duration of the decay time. As in the transmission phase, the analog ultrasonic transmitter 6 typically continues to convert the digital ultrasonic transmission signal 5 of the decay phase into a drive signal 7. However, during the decay of the piezoelectric oscillating element 8, the drive signal 7 of the decay phase now extracts mechanical oscillation energy from the piezoelectric oscillating element 8. For this purpose, the analog ultrasonic transmitter 6 preferably drives the piezoelectric oscillating element 8 using an inverted drive signal 7. In many cases, the ultrasonic transmitter 6 switches its internal resistance during the decay phase, such that the internal resistance converts the maximum energy of the piezoelectric oscillating element 8 into heat energy. These measures shorten the duration of the oscillation time of the oscillating element 8 after the end of the transmission phase. However, the ultrasonic transducer 9 is not ready to receive during the settling time. However, during this settling time, the emitted ultrasonic pulse train 10 has already traversed a non-negligible distance in the free space between the ultrasonic transducer 9 and the potentially present object 11. Half of the distance covered by the emitted ultrasonic pulse train 10 during the settling time is the close range of the ultrasonic sensor 1 in the sense presented herein. Therefore, without special measures, the ultrasonic sensor 1 cannot reliably detect the object 11 located within this close range of the ultrasonic sensor 1.

[0010] After the decay phase ends, the incoming reflected ultrasonic pulse train 12 then re-excites the piezoelectric oscillating element 8 of the ultrasonic transducer 9, causing it to vibrate mechanically. These new mechanical oscillations of the piezoelectric oscillating element 8 during the receiving phase result in an electro-ultrasonic received signal 13. Therefore, the piezoelectric oscillating element 8 of the ultrasonic transducer 9 generates an electro-ultrasonic received signal 13 based on the received, input, reflected ultrasonic pulse train 12. The amplifier 14 of the ultrasonic sensor 1 detects the electro-ultrasonic received signal 13 and converts it into an amplified received ultrasonic electrical signal 15. If applicable, the amplifier 14 filters and amplifies the electro-ultrasonic received signal 13 into the amplified received ultrasonic electrical signal 15. Preferably, the amplified received ultrasonic electrical signal 15 includes an envelope signal that reflects the amplitude response of the electro-ultrasonic received signal 13 and therefore no longer has a pulse frequency. In many preferred applications, the amplified received ultrasonic electrical signal 15 also includes an optional analog phase signal that reflects the phase shift between the drive signal 7 and the corresponding signal portion of the electro-ultrasonic received signal 13. Therefore, amplifier 14 may include, for example, a synchronous demodulator that performs I / Q analysis of the electro-ultrasound received signal 13. Thus, for the purposes of this document, the amplified received ultrasonic electrical signal 15 may also include multiple signals derived by amplifier 14 from the electro-ultrasound received signal 13. These signals are not limited to envelope signals and / or phase signals in the sense of the present document. Preferably, analog-to-digital converter 16 of ultrasonic sensor 1 samples these signals of the amplified received ultrasonic electrical signal 15 at a sampling frequency and converts the amplified received ultrasonic electrical signal 15 into a digital ultrasonic received signal 17. Therefore, the digital ultrasonic received signal 17 may include multiple digital ultrasonic sub-signals. Preferably, analog-to-digital converter 16 of ultrasonic sensor 1 therefore samples one signal of the amplified received ultrasonic electrical signal 15 at a sampling frequency and converts that signal of the amplified received ultrasonic electrical signal 15 into a digital ultrasonic sub-signal of the digital ultrasonic received signal 17 associated with that signal. Thus, the digital ultrasonic sub-signals together form the digital ultrasonic received signal 17. If necessary, subsequent digital processing and filtering stages 18 in the signal path convert the digitized ultrasound received signal 17 into a filtered ultrasound received signal 19. The filtered ultrasound received signal 19 may also include several sub-signals. Preferably, the digital processing and filtering stages 18 of the ultrasound sensor 1 and / or the computer core 2 compress the filtered ultrasound received signal 19 into a compressed ultrasound received signal. In the simplest case, compression is a threshold comparison of the envelope signal value with a threshold value. The computer core 2 of the ultrasound sensor 1 transmits the compressed ultrasound received signal via a data bus 20 to the control unit 21 of the ultrasound sensor system 22, which is preferably connected to multiple ultrasound sensors 1 via the data bus 20 and / or via a further data bus. For example, the data bus may be a DSI3 data bus or a PSI5 data bus, etc.

[0011] As already mentioned, in the prior art, when the oscillating element 8 of the ultrasonic transducer 9 is not yet stationary, there is a problem in detecting the reflected ultrasonic pulse train 12 from an object 11 within close range of the ultrasonic sensor 1.

[0012] DE 10 2015 002 269 B3 is known from the prior art. Practical applications show that the method for detecting reflected ultrasonic pulse trains 12 from an object 11 at close range from an ultrasonic sensor 1 in DE10 2015 002 269 B3 is parameter- and temperature-dependent. Therefore, this method has not yet been used for vehicle safety-related ultrasonic sensors 1.

[0013] In the method described in DE 10 2015 002 269 B3, a first comparator 23 compares the electro-ultrasonic received signal 13 of the piezoelectric oscillating element 8 of the ultrasonic transducer 9 with a first threshold (e.g., the value of the first threshold signal 24) and generates a first comparator output signal 25. Preferably, the computer core 2 and / or the digital processing and filtering stage 18 evaluate the first comparator output signal 25.

[0014] In the method described in DE 10 2015 002 269 B3, a second comparator 26 compares the amplified ultrasonic received signal 15 from amplifier 14 with a second threshold (e.g., the value of the second threshold signal 27) and generates a second comparator output signal 28. In doing so, amplifier 14 has already generated the analog envelope signal. Preferably, the second comparator 26 compares the amplitude value of the envelope signal of amplifier 14 with a second threshold 105 of the second threshold signal 27, thereby generating the second comparator output signal 28. The gain of amplifier 14 is typically in the range of 20 dB to 60 dB. Preferably, computer core 2 and / or digital processing and filtering stage 18 evaluate the second comparator output signal 28 or the signal 31 derived therefrom. For this purpose, we first assume that the XOR gate 30 is transparent and that the output signal of the XOR gate 30 corresponds to the second comparator output signal 28. The function of the XOR gate 30 is described later herein, so this simplification is for better understanding only and is not applicable. Instead of EXOR gate 30, the device may also include more complex logic circuitry, preferably logic circuitry that is sometimes functionally equivalent to EXOR gate. Digital processing and filtering stage 18 may include EXOR gate 30 and its output signal 31. Computer core 2 and / or digital processing and filtering stage 18 may optionally analog digital processing and filtering stage 18 and / or EXOR gate 30 and its output signal 31.

[0015] The method taught in document DE 10 2015 002 269 B3 proposes a first time difference 101 between a first time point 102 for detecting a first edge change in the first comparator output signal 28 and a subsequent second time point 103 for detecting a second edge change in the second comparator output signal 25. Since the first threshold of the first threshold signal 24 is a very high first threshold based on an evaluation of the unamplified electrosonic received signal 13, and since the second threshold of the second threshold signal 105 is a very low second threshold based on an evaluation of the amplified ultrasonic received signal 15, the second time point 103 of the second edge change always follows the first time point 102 of the first edge change in time. This is because the second time point 103 of the second edge change requires a further reduction in the oscillation amplitude of the piezoelectric oscillating element 8 compared to the first time point 102 of the first edge change. Therefore, the method taught in document DE 10 2015 002 269 B3 uses a first time difference 101 between two time points. These two time points respectively mark the decrease in the amplitude of the envelope signal during oscillation to below two corresponding and very different thresholds. On the other hand, the method uses a first comparator 23, preferably whose comparison input is directly connected to the oscillating element 8 (high first threshold) via the electro-ultrasound receiving signal 13. Alternatively, the method uses the comparison input of a second comparator 26 to evaluate the envelope signal of the amplified electro-ultrasound receiving signal 15 (low threshold) after amplification (40-60 dB). During testing in the proposal development process, it was found that this first time difference 101 is highly temperature-dependent, which unfortunately has prevented commercial application to date.

[0016] However, near-field measurements in automotive ultrasonic sensor systems are now an absolute requirement. However, as mentioned above, the near-field method based on a temperature-dependent first time difference 101 described in DE 10 2015 002 269 B3 is parameter- and temperature-dependent. Therefore, the microelectronic circuits implemented to date do not support the method of DE 10 2015 002 269 B3. Summary of the Invention

[0017] Therefore, this proposal is based on the task of creating a solution that does not have the aforementioned disadvantages of the prior art and has further advantages. The aim is to specify a solution that reduces or avoids the dependence of the DE 10 2015 002 269 B3 process on temperature and parameters.

[0018] This task is addressed through the technical teachings of the independent claims. Further embodiments may be the subject of the dependent claims.

[0019] The ultrasonic sensor system 22 of the type described at the beginning solves the task according to the proposal because, compared with the prior art, the ultrasonic sensor 1 performs additional compensated measurements according to this proposal. Applications of the proposed method for operating the ultrasonic sensor system 22 can be found particularly in environmental sensing devices. For example, vehicles and / or robots and / or other mobile devices can use such environmental sensing devices. These environmental sensing devices can be, for example, parking assistance and / or collision avoidance devices. In the case of robots, the environmental sensing devices can also be used to generate virtual environmental maps in the robot's computer system. For example, such environmental sensing devices can be used to detect and classify various types of obstacles. Mobile devices in the literal sense proposed herein can be specifically, but are not limited to, devices such as electric handcarts, forklifts, delivery robots, transport robots, etc., and can also be flying bodies such as helicopters and / or drones.

[0020] Fixed installations can use the environmental sensing devices proposed herein to measure objects inside or outside the various fixed installations that are approaching, passing by, or moving away from the environmental sensing devices. For example, a parcel sorting system can use the environmental detection devices described herein to measure goods (i.e., parcels) on the conveyor belt of the parcel sorting system and sort them if necessary. Use in safety airlocks is also conceivable.

[0021] The ultrasonic sensor 1 generates one or more reference measurements via one or more additional compensation measurements 504, wherein the emitted ultrasonic pulse train 10 has only one pulse. For example, the computer core 2 of the ultrasonic sensor 1 and / or the control unit 21 of the ultrasonic sensor system 22 utilizes the temporally subsequent measurements of the primary ultrasonic measurement 505 of the ultrasonic sensor 1 to calculate this generated reference measurement or these generated reference measurements. For better understanding, the literature presented herein is referenced in this context. Figure 5 If the control unit 21 of the ultrasonic sensor system 22 performs calculations, the computer core 2 of the ultrasonic sensor 1 first transmits one or more reference measurement values ​​to the control unit 21 of the ultrasonic sensor system 22. Therefore, the computer core 2 and / or control unit 21 generate a corresponding compensation value based on one or more reference measurement values. If necessary, the computer core 2 and / or control unit 21 can generate a common reference measurement value based on multiple reference measurement values.

[0022] The following describes the proposed measurement sequence performed by the proposed ultrasonic sensor system 22 and its ultrasonic sensor 1.

[0023] In the first step, the ultrasonic sensor 1 of the ultrasonic sensor system 22 performs a first compensation measurement 504 using a short emitted ultrasonic pulse train 10. Preferably, the short emitted ultrasonic pulse train 10 consists of only a few pulses. Preferably, the short emitted ultrasonic pulse train 10 consists of only 5 pulses, more preferably 4 pulses, more preferably 3 pulses, more preferably 2 pulses, and more preferably 1 pulse. Therefore, for the compensation measurement 504, an emitted ultrasonic pulse train 10 with exactly one pulse is particularly preferred. Furthermore, this has the advantage that the short ultrasonic pulse train for the compensation measurement 504 has a particularly small proximity.

[0024] In the second, preferably temporally subsequent, step, the ultrasonic sensor 1 performs a second primary ultrasonic measurement 505 using a long-transmitted ultrasonic pulse train 10. Preferably, the long-transmitted ultrasonic pulse train 10 comprises more pulses than the short-transmitted ultrasonic pulse train 10. Preferably, the long-transmitted ultrasonic pulse train 10 comprises more than one pulse, more preferably more than two pulses, more preferably more than three pulses, more preferably more than four pulses, and more preferably more than five pulses. Thus, a long-transmitted ultrasonic pulse train 10 comprising more than five pulses is particularly preferred.

[0025] The method disclosed herein proposes to transmit an initial short ultrasonic pulse train 10 for compensation measurement 504. Subsequently, the ultrasonic transducer 9 of the ultrasonic sensor system 22 receives the short reflected ultrasonic pulse train 12 and converts it back into an electro-ultrasonic received signal 13. The ultrasonic sensor system 22 receives the first short reflected ultrasonic pulse train 12, which is represented as a first ultrasonic envelope signal 504 in the amplitude curve 107 of the envelope signal of the amplified ultrasonic electro-ultrasonic received signal 15. As taught in the technique of DE 10 2015 002 269 B3, based on the amplitude curve 107 of the envelope signal of the amplified ultrasonic electro-ultrasonic received signal 15 of the first ultrasonic envelope signal 504, the ultrasonic sensor system 22 determines a first time difference 101 between a first time point 102 of the first edge change of the first comparator output signal 25 and a subsequent second time point 103 of the second edge change of the second comparator output signal 28. The first threshold of the first threshold signal 24 is a very high first threshold due to the evaluation of the unamplified electro-ultrasonic received signal 13. The second threshold 105 of the second threshold signal 27 is a very low second threshold 105 due to the evaluation of the amplified ultrasonic received signal 15. Therefore, here, in the case of the first ultrasonic envelope signal 504, the second time point 103 of the second edge change also always follows the first time point 102 of the first edge change in time. This is especially because: compared with the first time point 102 of the first edge change, the second time point 103 of the second edge change requires a further decrease in the oscillation amplitude of the piezoelectric oscillating element 8.

[0026] The method disclosed herein proposes that, after a compensation measurement 504 is performed by transmitting a first short ultrasonic pulse train 10, the ultrasonic sensor system 22 performs a main ultrasonic measurement 505 by transmitting a second long ultrasonic pulse train 10. Subsequently, the ultrasonic transducer 9 of the ultrasonic sensor system 22 receives the long reflected ultrasonic pulse train 12 and converts it back into an electro-ultrasonic received signal 13. The ultrasonic sensor system 22 receives this second long reflected ultrasonic pulse train 12. This second long reflected ultrasonic pulse train 12 is represented as a second ultrasonic envelope signal 505 in the amplitude curve 107 of the envelope signal of the amplified electro-ultrasonic received signal 15. As taught in the technique of DE 10 2015 002 269 B3, based on the amplitude curve 107 of the envelope signal of the amplified electro-ultrasonic received signal 15 of the second ultrasonic envelope signal 505, the ultrasonic sensor system 22 now determines a second time difference 501. This is the second time difference 501 between the third time point 502 of the third edge change of the first comparator output signal 25 and the subsequent fourth time point 503 of the fourth edge change of the second comparator output signal 28. The first threshold of the first threshold signal 24 is also a very high first threshold due to the evaluation of the unamplified electro-ultrasound received signal 13. Similarly, the second threshold 105 of the second threshold signal 27 is also a very low second threshold 105 due to the evaluation of the amplified ultrasound received signal 15. Therefore, here, in the case of the second ultrasound envelope signal 505, the fourth time point 503 of the fourth edge change also always follows the third time point 502 of the third edge change in time. This is also because: compared with the third time point 502 of the third edge change, the fourth time point 503 of the fourth edge change requires a further decrease in the oscillation amplitude of the piezoelectric oscillating element 8.

[0027] The detailed explanation of the technical teachings in the literature presented here surprisingly reveals that the processes of temperature dependence at the first time difference 101 and the second time difference 501 are essentially similar. In this respect, the text presented herein refers to illustratively and schematically drawn diagrams. Figure 6 , Figure 6 These are the results of laboratory measurements.

[0028] First, the description presented here focuses on an embodiment where the envelope filter 14 is part of an analog input amplifier. Figure 1 The embodiment is illustrated schematically and in a generally simplified manner.

[0029] The method presented here essentially uses the method of DE 10 2015 002 269 B3, but instead of using the first time difference of 101 or the second time difference of 501 as the input value for DE 10 2015 002 269 B3, it uses the following values:

[0030] The difference of 601 between the first time difference of 101 and the second time difference of 501, and / or

[0031] The difference of 601 between the second time difference of 501 and the first time difference of 101, and / or

[0032] The ratio of the second time difference 501 to the first time difference 101 and / or

[0033] The ratio of the first time difference 101 to the second time difference 501 and / or

[0034] The combination of the values ​​of the first time difference 101 and the second time difference 501 is equivalent to the three comparison methods mentioned above, and is used to compare the value of the first time difference 101 with the value of the second time difference 501.

[0035] Preferably, the computer core 2 and / or the digital processing and filtering stage 18 use this comparison method. Preferably, the computer core 2 and / or the digital processing and filtering stage 18 record a first time difference 101 and / or a second time difference 501 for this purpose.

[0036] In a more simulation-oriented embodiment, the technical teachings described herein provide a first comparator 23, which is preferably directly connected to the electro-ultrasonic received signal 13 of the oscillating element 8 of the ultrasonic transducer 9. Preferably, the first comparator 23 directly compares the ultrasonic transducer output voltage of the electro-ultrasonic received signal 13 with a fixed first threshold of the first threshold signal 24. Figure 1 The first comparator output signal 25 of the first comparator 23 is illustrated as an example. The first comparator 23 can also be implemented in the digital section to influence signal evaluation. Furthermore, if necessary, the computer core 2 can simulate the first comparator 23 as a comparison operation. In the latter two cases, it is convenient if the analog-to-digital converter 16 is positioned accordingly earlier in the signal path. In this respect, the documents disclosed herein are referenced by way of example. Figure 4 In the following, the document disclosed herein describes by way of example an implementation of a first comparator 23, which limits the technical teachings of the document disclosed herein to comparisons implemented by analog circuitry as the first comparator 23.

[0037] As long as the amplitude of the electro-ultrasonic received signal 13 of the ultrasonic transducer 9 remains at a significant level, the first comparator output signal 25 of the exemplary first comparator 23 typically exhibits digital oscillation. Typically, the fixed first threshold used by the exemplary first comparator 23 of the ultrasonic sensor system 22 to compare the transducer voltage amplitude of the electro-ultrasonic received signal 13 of the ultrasonic transducer 9 has a value such that, in cases such as when the temperature of the ultrasonic sensor system 22 changes, even in the presence of a very close object within the vicinity of the ultrasonic sensor 1, the first time point 102 or the third time point 502 at the end of the oscillation within the transmission cycle does not shift or only shifts by a few oscillation clock cycles. Therefore, for example, by digitally smoothing and filtering the first comparator output signal 25 of the first comparator 23, the digital processing and filtering stage 18 or the computer core 2 can reliably detect the end of the decay time at the first time point 102 of the first edge change 102 of the first comparator output signal 25 or the third time point 502 of the third edge change 502 of the first comparator output signal 25 within the transmission cycle. The transmission cycle, as defined in this paper, begins at the start of the first pulse of the first ultrasonic pulse train and ends at the start of the first pulse of the immediately following ultrasonic pulse train. Through the first temperature-dependent time difference 101, the first time point 102 of the first edge change 102 of the first comparator output signal 25 is typically before the second time point 103, at which the envelope signal of the amplified electro-ultrasonic received signal 15 drops below the second threshold signal 27. However, due to the large amplitude, this second time point 103 is practically unrelated to the feedback effect caused by sound reflections on the ultrasonic transducer 9. The third time point 502 of the third edge change 502 of the first comparator output signal 25 is also before the fourth time point 503, where the envelope signal of the amplified electro-ultrasonic received signal 15 is down-stamped by the second threshold signal 27 through the temperature-dependent second time difference 501; however, due to the large amplitude, this third time point 502 is practically unrelated to the feedback effect of sound reflections on the ultrasonic transducer 9.

[0038] Now, the digital processing and filtering stage 18 or the computer core 2 preferably refers, for example, to the first time point 102 of the first edge change 102 of the first comparator output signal 25 or to the third time point 502 of the third edge change 502 of the first comparator output signal 25, allowing the second comparator output signal 28 of the second comparator 26 to emit an echo received signal only after the timer 41 has elapsed a corresponding subsequent third time difference, following evaluation of the amplified electro-ultrasound received signal 15. The timer 41 is preferably part of the digital processing and filtering stage 18. The digital processing and filtering stage 18 typically controls the timer 41 in response to the output signal 31 of the EXOR gate 30 or the output signal of a third logic circuit 30 functionally equivalent to an EXOR gate. Furthermore, the digital processing and filtering stage 18 typically controls the timer 41 in response to the first comparator output signal 25. Preferably, the computer core 2 can also be controlled by... Figure 4 One or more signal lines are shown to control and / or influence timer 41. Alternatively, computer core 2 can implement the function of timer 41, for example, through simulation, and influence the envelope filter via signal line 33. Preferably, when the first time point 102 is reached or when the third time point 502 is reached, the second comparator 26 starts timer 41 via signaling that can be executed, for example, via digital processing and filtering stage 18.

[0039] The first comparator output signal 25 of the first comparator 23 indicates the start of the decay process of the ultrasonic transducer 9 by a first edge change 102 at a first time point 102 or by a third edge change 502 at a third time point 502. The second comparator output signal 28 of the second comparator 26 indicates the end of the decay process of the ultrasonic transducer 9 by a second edge change 103 at a second time point 103 or by a fourth edge change 503 at a fourth time point 503.

[0040] Minor modifications may cause the second comparator output signal 28 of the second comparator 26 to indicate a correction for the reflection. For example, the EXOR gate 30 or its functionally equivalent logic circuitry may, for instance, at least temporarily, signal the end of decay of the oscillating element 8 of the ultrasonic transducer 9. Preferably, the second comparator output signal 28 of the second comparator 26 and the EXOR control signal 32 of the digital processing and filtering stage 18 or the computer core 2 form preferred inputs to the EXOR gate 30 or the logic circuitry. Preferably, the output 31 of the EXOR gate 30 forms the input signal to the digital processing and filtering stage 18.

[0041] For this purpose, EXOR gate 30 or the logic circuit switches the second comparator output signal 28 of the second comparator 26 to a first logic level. This is preferably done at the end of the transmission phase of the ultrasonic transducer 9 during a predetermined third time period associated with the first time point 102 or the third time point 502. Thus, the first comparator output signal 25 of the first comparator 26 signals the end of the transmission phase of the ultrasonic transducer 9. The first comparator 23 detects the first time point 102 or the third time point 502 of the decay of the ultrasonic transducer 9. Preferably, the length of this third time period corresponds to the length of the first time difference 101 without a reflecting object. Preferably, the ultrasonic sensor system 22 determines the duration of the first time difference 101 by means of short ultrasonic pulses in the exemplary compensation measurement 504. This is in Figure 2 and Figure 5 As shown in the figure. Preferably, the length of the third time period does not depend on the length of the second time difference 501. That is, the document proposed herein suggests that the length of the third time period is determined based on a detected first time difference 101, which is determined by the ultrasonic sensor system 22 using a short ultrasonic pulse train 504 in an exemplary compensation measurement 504.

[0042] Now, if object 11 is spatially close to ultrasonic transducer 9, the early arrival echo of the early-arriving reflected ultrasonic pulse train 12 raises the amplitude curve 107 of the envelope within the corresponding time range. However, the fourth time point 503 is now shifted backward in time. Since the short ultrasonic pulse of compensation measurement 504 has a small near-range, there is a range within which the second time point 103 has not yet shifted backward in time. Due to the EXOR circuit of EXOR gate 30, or if a corresponding alternative logic circuit is suitably designed, the output of EXOR circuit 30 switches the first comparator output signal 25 of first comparator 23 to the inverted logic value corresponding to the echo, the first comparator output signal 25 previously present at the output 31 of EXOR gate 30. Now, the surprising finding disclosed here is that, firstly, compared to the prior art, the ultrasonic sensor system 22 here is now able to detect object 11 within the near range of ultrasonic sensor system 22, but cannot determine the exact location of object 11. However, by using the value of the first time difference 101 as the charge value of the counter of timer 41, this detection is no longer dependent on temperature and is therefore useful. When the count value of the counter of timer 41 reaches this load value, timer 41 drives the EXOR gate 30 or the EXOR control signal 32 of the third logic circuit. Thus, the digital processing and filtering stage 18 detects the presence of object 11 in the near field. With this proposed method, the exact position of object 11 at close range cannot be determined. However, for most applications, it is perfectly sufficient to have detected the presence of object 11 at this close range. So far, these measures have improved the receiving behavior of the ultrasonic sensor system 22 at close range.

[0043] However, it has been further shown that the digital processing and filtering stage 18 or the computer core 2 should perform optimized adjustments to the filtering of the envelope signal of the amplified electro-ultrasonic received signal 15 and the comparator output signals 28, 25 in parallel with the measures described above, in order to obtain practically useful results in the automotive field. These two measures, one described above and one described below, themselves produce improvements. However, based on experience, these two measures are generally insufficient on their own for automotive applications.

[0044] The following sections relate to the parameterization of the envelope filter, particularly for the timing of the primary ultrasound measurement 505. In contrast to the prior art, according to the proposal, one or more parameters of the envelope filter depend on the values ​​of a first time point 102 and / or a second time point 103 and / or a first time difference 101, preferably determined by the ultrasound sensor system 22 using a compensation measurement 504 that preferably follows immediately in time.

[0045] Therefore, the literature presented herein further proposes that the ultrasonic sensor system 22 employs a method for adjusting the parameters of the envelope filter in the amplifier 14 to filter the envelope signal of the amplified ultrasonic electrical received signal 15. For the purposes of this literature, the amplifier 14 may include an envelope filter with bandpass characteristics. The proposed method again determines a second time point 103, at which the instantaneous value of the amplitude of the envelope signal of the amplified ultrasonic electrical received signal 15 is lower than the second threshold 105 of the second threshold signal 27. Now, the literature presented herein proposes that, based on this specific second time point 103, for example, the computer core 2 or digital processing and filtering stage 18 switches the bandpass characteristics of the envelope filter of the amplifier 14, making the bandpass characteristics of the envelope filter of the amplifier 14 narrower. This decrease in the instantaneous value of the envelope signal of the amplified ultrasonic electrical received signal 15 below the second threshold 105 of the second threshold signal 27 occurs at the second time point 103 during the compensation measurement 504 or at the fourth time point 503 during the main ultrasonic measurement 505. Preferably, the bandpass characteristic of the envelope filter of amplifier 14 is narrower within a time range immediately preceding the switching at the second time point 103 or the fourth time point 503. At the end of the ultrasonic pulse cycle, the digital processing and filtering stage 18 and / or the computer core 2 preferably resets the relevant parameters of the envelope filter and / or amplifier 14 and / or other device parts of the ultrasonic sensor system 22 and / or ultrasonic sensor 1 to the initial values ​​intended for the start of the ultrasonic pulse cycle. This generally does not apply to the length of the detected first time difference 101, which is preferably maintained until the next measurement of the duration of the first time difference 101 by means of a short ultrasonic pulse in compensation measurement 504. Subsequently, the value of the envelope signal of the amplified ultrasonic electro-received signal 15 decreases at a gentler slope. With such a second threshold signal 27, a near-field object 11 arriving shortly after the ultrasonic pulse train emission with a so-called "near echo" no longer causes the envelope signal of the amplified electro-ultrasonic received signal 15 to drop below the second threshold 105 of the second threshold signal 27. Then, the ultrasonic sensor system 22 may no longer need to determine the fourth time point 503. Preferably, the digital processing and filtering stage 18 and / or the computer core 2 and / or the ultrasonic sensor system 22 and / or the ultrasonic sensor 1 then use a value of the transmission period corresponding to the distance between the two pulses as a substitute value. Preferably, they then use this value as a substitute value for the second time difference 501. However, a near-field object 11 with a so-called "very close echo" arriving shortly after the transmission of the short ultrasonic pulse train 10 can also cause a negative pulse signal at a later time than the second threshold 105 of the second threshold signal 27 at the first time point 102, through the envelope signal of the amplified electro-ultrasonic received signal 15.The reason is that the oscillation of the ultrasonic transducer 9 has not yet ended, and the object 11 is so close that the short ultrasonic pulse train of the compensation measurement 504 is also disturbed.

[0046] This paper proposes that the digital processing and filtering stage 18 or computer core 2 progressively switches the envelope filter during the transmission period. Preferably, the envelope filter is the envelope filter of amplifier 14. In extreme cases, this switching can be accomplished in such a way that the digital processing and filtering stage 18 or computer core 2 continuously readjusts the analog components of the envelope filter, which are determined by signaling to amplifier 14 via control lines not shown in the figure to determine the characteristic frequency. The digital processing and filtering stage 18 or computer core 2 preferably performs the switching or readjustment of the envelope filter according to the time elapsed since the first time point 102, and the envelope filter is typically a bandpass filter. Generally, the switching or readjustment involves the characteristic frequency and / or amplitude of the transfer function of the envelope filter. Various possibilities for defining the time value of the past time period are possible:

[0047] The elapsed time period can be the duration of the time period that begins at the end of the transmission phase at the second time point 103 or the fourth time point 503, starting from the time the drive stage of the ultrasonic transducer 9 is turned off. Preferably, the digital processing and filtering stage 18 or the computer core 2 switches and / or readjusts the parameters of the envelope filter according to the time from the second time point 103 or the fourth time point 503.

[0048] Alternatively, or in parallel over time, the digital processing and filtering stage 18 or the computer core 2 can switch and / or readjust the parameters of the envelope filter based on a time from the first time point 102 already discussed or from the third time point 503, from which point the first comparator output signal 25 of the first comparator 23 no longer exhibits oscillation.

[0049] Alternatively, or in parallel over time, the digital processing and filtering stage 18 or the computer core 2 may also switch and / or readjust the parameters of the envelope filter based on the envelope signal of the amplified ultrasonic electrical received signal 15.

[0050] In the latter case, gradual switching may require additional comparators or devices that are functionally equivalent to these comparators, which utilize corresponding alternative switching threshold signals to perform these switching based on corresponding alternative switching thresholds.

[0051] Preferably, the threshold generating device 29 generates threshold signals 24 and 27, as well as other possible threshold signals. Preferably, the digital processing and filtering stage 18 and / or the computer core 2 controls the threshold generating device 29, the generation of threshold signals 24 and 27, and the generation of any other threshold signals by the threshold generating device 29. Preferably, the threshold generating device 29 generates threshold signals 24 and 27 based on the time since the first time point 102, the time since the third time point 502, and / or based on the time since the second time point 103 or the time since the fourth time point 503, and / or based on the first time difference 101, and generates other threshold signals if applicable.

[0052] As a result, a faster falling edge was obtained in the amplitude curve 107 of the amplified electro-ultrasound received signal 15, which enabled the ultrasonic sensor system 22 to detect the reflection of the object 11 at close range earlier.

[0053] Adapting to the typical envelope curve of the system, corresponding to the amplitude curve 107 of the envelope signal of the amplified electro-ultrasound received signal 15, a second threshold signal 27 that decreases exponentially can now be specified. In this case, the second comparator 26 detects, for example, that the amplitude curve 107 of the envelope signal of the amplified electro-ultrasound received signal 15 is below the second threshold signal 27. This occurs at a second time point 103 or a fourth time point 503. Within the transmission period, with a third time interval delayed relative to the first time point 102, the exponential decay of the value of the second threshold signal 27 begins with a predetermined or determined first time constant τ1, starting from a predetermined or otherwise determined remaining threshold. Preferably, the duration of the third time interval depends on the duration of the first time difference 101 or the difference 601 between the second time difference 501 and the first time difference 101.

[0054] Therefore, in one aspect, the basic method is a method for evaluating the electro-ultrasonic received signal 13 of the piezoelectric ultrasonic transducer 9. Here, in a first step, a first comparator 23 or a functionally equivalent device compares the instantaneous value of the electro-ultrasonic received signal 13 of the ultrasonic transducer 9, or the signal derived from the electro-ultrasonic received signal 13, with a first threshold, and forms a first comparator output signal 25, etc., based on the result. Preferably, in a second step of the basic method, an amplifier 14 forms an amplified ultrasonic electro-received signal 15, while simultaneously amplifying and filtering the electro-ultrasonic received signal 13, preferably, the amplified ultrasonic electro-received signal 15 includes an envelope signal. Preferably, the amplifier 14 includes an envelope filter, preferably, the envelope filter is inserted in the signal forming path of the amplifier 14 for forming the envelope signal. Preferably, the filtering parameters in the envelope filter of the amplifier 14 are designed to be switchable or controllable. In a next step of the basic method, a threshold generating device 29 forms a first threshold signal 24 and a second threshold signal 27, as well as other possible threshold signals. Specifically, the threshold generation device 29 can generate threshold signals 24 and 27, as well as other threshold signals, by filtering from the envelope signal of the amplified ultrasonic electroacoustic received signal 15. Furthermore, the threshold generation device 29 can generate threshold signals 24 and 27, as well as other threshold signals, by filtering from the electro-ultrasonic received signal 13 of the ultrasonic transducer 9. Typically, in this case, the second threshold signal 27 is compared to the first threshold signal 24 such that the first comparator 23 switches at a higher amplitude than the second comparator 26 in the electro-ultrasonic received signal 13. Then, the second comparator 26 compares the amplitude curve 107 of the envelope signal with the second threshold 105 of the second threshold signal 27. The output signal 28 of the second comparator 26 reproduces the detected echo. At close range, the output signal 31 of the EXOR gate 30 reproduces the detected echo, and the signal at close range only indicates that the object is at close range. Therefore, if needed, the computer core 2 can directly send the output signal 28 of the second comparator 26 or the output signal 31 of the EXOR gate 30 to the control unit 21. According to the invention, the detection of the first time point 102 or the third time point 502 of the attenuation of the ultrasonic transducer 9 is particularly important. This is accomplished by detecting the first time point 102 or the third time point 502 when the output 25 of the first comparator 23 no longer displays a signal after the control of the ultrasonic transducer 9 has been turned off. This event at the first time point 102 or the third time point 502 is typically initiated by the digital processing and filtering stage 18, which starts the timer 41. The computer core 2 and / or the digital processing and filtering stage 18 stops the timer 41 at the end of the transmission cycle and then preferably resets the timer 41 to a predetermined value. The timer 41 may be part of the digital processing and filtering stage 18 and / or the computer core 2. The computer core 2 may simulate the timer 41. Figure 1In the example, timer 41 is not, by way of example, part of the digital processing and filtering stage 18.

[0055] According to the example, within a predetermined first time period Δt1 after the ultrasonic transducer (TR) decays to a corresponding other logic value at a first time point 102 or a third time point 503, the timer 41 switches the second output signal 28 of the second comparator 26. For example, from 1 to 0, and vice versa, depending on the system design.

[0056] The device according to the invention, in the form of an ultrasonic sensor system 22, corresponds to the method according to the invention described above, and the device at least partially performs the corresponding method. The device according to the invention is used to detect the presence of an object at close range in an ultrasonic measurement system according to the invention (particularly in a car). It has an ultrasonic transducer 9, the voltage signal of which is detected. An envelope generating device, as part of the amplifier 14 of the ultrasonic sensor 1 of the device, determines the envelope signal of the amplified electro-ultrasonic received signal 15 based on the electro-ultrasonic received signal 13 of the ultrasonic transducer 9. A threshold generator 29, also as part of the device, generates a second threshold signal 27 having a second threshold 105. Furthermore, the device includes a second comparator 26, which compares the second threshold 105 of the second threshold signal 24 with the amplitude curve 107 of the envelope signal of the amplified ultrasonic electro-ultrasonic received signal 15. As a result of this comparison, the second comparator generates a second comparator output signal 28 of the second comparator 26. Typically, the second comparator output signal 28 of the second comparator 26 is thus inverted or set to a fixed value by a control signal via logic circuitry (e.g., EXOR gate 30), particularly according to logic 1 in the example. Furthermore, the device typically includes a first comparator 23 that compares the value curve of the electro-ultrasound received signal 13 of the ultrasonic transducer 9 with a first threshold of a first threshold signal 24, wherein the first threshold of the first threshold signal 24 is selected compared to a second threshold 105 of the second threshold signal 27, such that the first comparator 23 switches at a higher value than the second comparator 26 for the electro-ultrasound received signal 13 of the ultrasonic transducer 9. As previously described, the device includes a timing detection device that determines a first time point 102 or a third time point 502 after the active actuation of the ultrasonic transducer 9 has ended, at which time the value of the electro-ultrasound received signal 13 of the ultrasonic transducer 9 is no longer sufficient to cause the first comparator 23 to switch.

[0057] The time detection device starts a timer 41 by means of a start signal. The timer 41 is part of the device, which, through a control signal detected at a first time point 102 or a third time point 502, switches the second comparator output signal 28 of the second comparator 26 to a state corresponding to a logic value within a first time period (Δt1) in a manner as if no reflection exists. Preferably, the switching device is a logic 30 or a functionally equivalent device. Preferably, the computer core 2 and / or the digital processing and filtering stage 18 control this switching via control signaling 32. The logic circuit may include an EXOR gate 30. In this case, the EXOR control signal 32 can then send signaling to the EXOR gate 30.

[0058] Furthermore, the proposed device preferably has a further feature that itself leads to improvements beyond the prior art, but which itself does not yet meet the modern requirements of the automotive market. Such a device for detecting the presence of an object at close range within the ultrasonic measurement system also includes an ultrasonic transducer 9, whose electro-ultrasonic received signal 13 is detected. Preferably, the device includes an envelope generating device as part of an amplifier 14, which determines the envelope signal of an amplified electro-ultrasonic received signal 15 based on the electro-ultrasonic received signal 13 of the ultrasonic transducer 9. Therefore, the envelope generating device preferably includes a controllable envelope filter. The proposed device also includes: a threshold generating device 29 that generates a second threshold signal 27 having a second threshold 105; and a second comparator 26 that compares the second threshold signal 27 with the amplitude curve 107 of the envelope signal of the amplified electro-ultrasonic received signal 15, and generates a second comparator output signal 28. During device operation, the computer core 2 and / or the digital processing and filtering stage 18 change at least one characteristic frequency of the controllable envelope filter of the amplifier 14 at at least one time point according to the second comparator output signal 28 of the second comparator 26 or in relation to the second comparator output signal 28 of the second comparator 26.

[0059] In another embodiment, the device further includes a first comparator 23 that compares the electro-ultrasound received signal 13 of the ultrasonic transducer 9 with a first threshold of a first threshold signal 24, wherein, preferably, the first threshold of the first threshold signal 24 is also selected compared with a second threshold 105 of a second threshold signal 27, such that the first comparator 23 switches at a higher value of the electro-ultrasound received signal 13 of the ultrasonic transducer 9 compared with a second comparator 26. For timing control, the device also preferably includes the timing determination device. This determines a first time point 102 or a third time point 502 after the end of the active control time of the ultrasonic transducer 9, from which the value of the electro-ultrasound received signal 13 of the ultrasonic transducer 9 is no longer sufficient to cause the first comparator 23 to switch. Thus, a fixed time reference point is created, and the control task can now be enabled. Based on the elapsed time associated with the first time point 102 or the third time point 502, the control task of the envelope filter of the amplifier 14 and the threshold generation device 29 can now be performed in a time-dependent manner. For this purpose, the device typically includes a timer 41. The timer 41 may be part of a digital processing and filtering stage 18, which preferably changes the filtering characteristics of the envelope filter of the envelope generation device in the amplifier 14 at least twice, after at least a third time period (Δt3) and at least a fourth time period (Δt4) with respect to the first time point 102 and the third time point 502, respectively. Of course, it is conceivable that such changes can be made a very large number of times, resulting in quasi-continuous changes in the parameters of the second threshold signal 27 and / or the envelope filter, starting from the first time point 102 or the third time point 502. In extreme cases, the timer 41 may be an analog device that generates an analog signal, for example, by means of a level that represents the elapsed time period in a linear or nonlinear but strictly monotonically decreasing or strictly monotonically increasing manner, and continuously controls one or more parameters of the second threshold signal 24 and / or the envelope filter.

[0060] In the case of discrete control, for example by means of a digital timer, the timer 41 can also control the threshold generating device 29 after at least a fifth time period (Δt5) related to the first time point 102 or the third time point 502 in such a way that the second threshold 105 of the second threshold signal decreases exponentially from the first time point 102 or the third time point 502 to the remaining threshold with a first time constant τ1.

[0061] The analog ultrasonic transmitter stage 6 of the ultrasonic sensor 1 typically controls the ultrasonic transducer 9 using the control signal 7 at the beginning of the transmission cycle during the transmission phase. After the transmission phase, the analog ultrasonic transmitter stage 6 controls the ultrasonic transducer 9 during the braking phase, causing it to lose as much energy as possible in a short time to oscillate as quickly as possible. After the braking phase ends, the ultrasonic transducer 9 continues to oscillate during the decay phase. Preferably, after the ultrasonic transducer 9 has already oscillated during the oscillation phase, the remaining portion of the transmission cycle of the analog ultrasonic transmitter stage 6 during the receiving phase is inactive. The remaining portion of the transmission cycle after the transmission and deceleration phases is divided into a steady-state period and a receiving period. The transmission cycle typically repeats periodically. The first comparator 23 compares the value of the electro-ultrasonic received signal 13 of the ultrasonic transducer 9 with a first threshold signal 24, which is typically generated by the threshold generating device 29. The first threshold is selected such that it is more effective than the second threshold 105 of the second threshold signal 27. Preferably, the first comparator output signal 25 of the first comparator 23 is evaluated by a time-point detection device. The time point detection device is preferably part of the digital processing and filtering stage 18. The computer core 2 can also be used as the time point detection device. After the active control of the ultrasonic transducer 9 ends, the time point detection device determines a first time point 102 or a third time point 502, after which the value of the electro-ultrasonic receiving signal 13 of the ultrasonic transducer 9 is no longer sufficient to switch the first comparator 23. Typically, the first time point 102 or the third time point 502 exists at the output of the time point detection device in the form of a suitable corresponding signal. This signal typically activates timer 41. Timer 41 can be part of the digital processing and filtering stage 18. The computer core 2 can also operate as timer 41, or include such timer 41. Therefore, preferably, timer 41 is activated when the first time point 102 or the third time point 502 is reached within the transmission cycle. The end of the transmission cycle or the beginning of the transmission cycle preferably resets timer 41. Timer 41 is typically activated when the analog ultrasonic transmitting stage 6 of the ultrasonic sensor 1 is turned off. In a first embodiment, within a first time period (Δt1), starting from a first time point 102 or a third time point 502 in the relevant transmission cycle, timer 41 typically switches the second comparator output signal 28 of the second comparator 26 to a state corresponding to the logic value of the second comparator output signal 28 when there is no reflection, by means of logic control signal 32 and logic circuit 30. In a second, less preferred embodiment, by another control line, timer 41 changes the filtering characteristics of the envelope filter of the envelope generation device of amplifier 14 at least twice within the transmission cycle after at least a third time period (Δt3) and at least a fourth time period (Δt4) with respect to the first time point 102 and the third time point 502, respectively.It is also conceivable to have a quasi-continuous or continuous change with a function of change starting from the fifth time point, which is shifted by a third time interval Δt3 relative to the first time point 102 or the third time point 502. Particularly preferred is that the filtering characteristics of the envelope filter of the envelope generation device within amplifier 14 are changed at four time points after the first time point 102 or the third time point 502. However, compared to the control of the filtering characteristics by timer 41, it is preferable to control the envelope filter by means of filter control and based on the second comparator output signal 28 of the second comparator 26. Therefore, filter control is preferably part of the digital processing and filtering stage 18. The computer core 2 can also be used for filter control. In the third embodiment, after at least a fifth time period (Δt5) relative to the first time point 102 or the third time point 502 of the transmission period, the timer 41 preferably changes the threshold generation of the threshold signals 24 and / or 27 and possibly other threshold signals by means of the threshold generation device 29 in such a way that the second threshold 105 of the second threshold signal 27 generated by the threshold generation device 29 decreases exponentially from that time point (Δt5) to the remaining threshold with a first time constant τ1.

[0062] It will be apparent to those skilled in the art that the functionality shown in this block diagram can also largely function as software on a signal processor. In this respect, one or more components of this block diagram can also be combined into a single device in an implementation.

[0063] The following sections involve... Figure 4 Similar devices. With Figure 1 The essential difference is that the analog-to-digital converter 16 performs analog-to-digital conversion in the received signal path, not after the envelope signal is generated by the envelope filter in amplifier 14, but before the envelope signal is generated in a separate envelope filter 33 located later in the received signal path. Figure 4 In the example, envelope filter 33 is therefore executed separately from amplifier 14. Otherwise, the process is largely the same in an analog manner.

[0064] For the purposes of this text, the ultrasonic sensor system 22 includes one or more ultrasonic sensors 1 and one or more data buses 20. The data buses 20 connect the ultrasonic sensors 1 to a control unit 21 of the ultrasonic sensor system 22, which typically includes one or more computer systems with memory, etc. For the purposes of this text, the ultrasonic sensor system 22 includes at least one ultrasonic transducer 9 and an evaluation circuit 37. Preferably, a possible implementation of the proposed evaluation circuit 37 may digitally implement one part of the evaluation circuit 37 of the ultrasonic sensor 1 and analogically implement another part. Therefore, preferably, the evaluation circuit 37 of the ultrasonic sensor 1 according to this proposal includes a digital section 35 and an analog section 36.

[0065] Preferably, the ultrasonic sensor 1 has one or more voltage regulators 39 that supply electrical energy from one or more energy sources to the device portions of the digital section 35 and / or the device portions of the analog section 36. Preferably, positive power supply voltage lines 38 and 40 supply electrical energy to the voltage regulators 39, which in turn at least partially transfer electrical energy to other device portions. For simplicity, these voltage regulators 39 are not shown in most figures. If applicable, the computer core 2 controls these voltage regulators 39 wholly or partially. The positive power supply voltage lines 38 and 40 may also be part of the data bus 20. The positive power supply voltage lines 38 and 40 may also be used as data lines of the data bus 20.

[0066] Preferably, the digital portion 35 of the drive circuit 37 includes a computer core 2, a control signal 4 for the digital ultrasonic pulse train generator 2 of the ultrasonic sensor 1, the digital ultrasonic pulse train generator 3 of the ultrasonic sensor 1, a digital ultrasonic receiving signal 17, an envelope filter 33, a processed digital ultrasonic receiving signal 34 that is an envelope signal or preferably includes an envelope signal, a digital processing and filtering stage 18, and a filtered ultrasonic receiving signal 19. Preferably, the digital portion 35 of the drive circuit 37 includes a second digital comparison logic circuit, which is functionally equivalent to the second comparator 26, and compares the second threshold signal 27 with the processed digital ultrasonic receiving signal 34, which is an envelope signal or preferably includes an envelope signal. Thus, the second digital comparison logic circuit compares the value of the second threshold signal 27 with the value of the processed digital ultrasonic receiving signal 34 and forms the value of the second comparator output signal 28. Preferably, in this embodiment, the second threshold signal 27 is a digital signal formed by the threshold generation device 29. In this particularly simple case, for clarity, the corresponding sub-device of the threshold generation device 29 may be, for example, a register, which the computer core 2 can write data values ​​to via the internal data bus of the digital portion 35 (not shown in the figure) and preferably can also read the register.

[0067] Preferably, the analog section 36 includes an analog ultrasonic transmitting stage 6 of the ultrasonic sensor 1. The analog ultrasonic transmitting stage 6 of the ultrasonic sensor 1 converts the digital ultrasonic transmitting signal 5 into an analog driving signal 7 of the ultrasonic sensor 1. The driving signal 7 of the ultrasonic sensor 1 drives the oscillating element 8 of the ultrasonic transducer 9. Preferably, the ultrasonic transmitting stage 6 of the ultrasonic sensor 1 has high impedance during the time receiving phase after the transmission and decay phases to prevent overloading of the output signal of the oscillating element 8, i.e., the electro-ultrasonic receiving signal 13. Preferably, the amplifier 14 amplifies and filters the electro-ultrasonic receiving signal 13 to obtain an amplified electro-ultrasonic receiving signal 15. The amplifier 14 and the amplified electro-ultrasonic receiving signal 15 are preferably part of the analog section 36 of the drive circuit 37.

[0068] Preferably, the analog-to-digital converter 16 converts the amplified electro-ultrasound received signal 15 into a digital ultrasound received signal 17. The analog-to-digital converter 16 is typically considered as part of the analog portion 36 of the drive circuit 37 of the ultrasound sensor 1.

[0069] Therefore, contrary to the previous example, in this example, the envelope filter 33 is not part of the amplifier 14 in the analog section 36 of the drive circuit 37 of the ultrasonic sensor 1, but rather part of the digital section 35 of the drive circuit 37. Contrary to the previously mentioned example, the envelope filter 33 is considered to move along the signal path toward the digital processing and filtering stage 18.

[0070] The method presented here essentially uses the method of DE 10 2015 002 269 B3, but instead of using the first time difference of 101 or the second time difference of 501 as the input value for DE 10 2015 002 269 B3, it uses the following values:

[0071] • The difference of 601 between the first time difference of 101 and the second time difference of 501 and / or

[0072] • The difference of 601 between the second time difference of 501 and the first time difference of 101 and / or

[0073] • The ratio of the second time difference 501 to the first time difference 101 and / or

[0074] • The ratio of the first time difference 101 to the second time difference 501 and / or

[0075] The combination of the values ​​of the first time difference 101 and the second time difference 501 is equivalent to the three comparison methods mentioned above, and is used to compare the value of the first time difference 101 with the value of the second time difference 501.

[0076] Preferably, the computer core 2 and / or the digital processing and filtering stage 18 use this comparison method. Preferably, the computer core 2 and / or the digital processing and filtering stage 18 record a first time difference 101 and / or a second time difference 501 for this purpose.

[0077] In the more digitally oriented embodiment described herein, the technical teachings presented herein preferably place the first comparator 23 in the analog section 36, which is preferably directly connected in this digital reconfiguration to the analog electro-ultrasonic received signal 13 of the oscillating element 8 of the ultrasonic transducer 9. The first comparator 23 preferably again directly compares the analog output voltage of the ultrasonic transducer 9 of the electro-ultrasonic received signal 13 with a fixed analog first threshold of the first threshold signal 24. However, the first comparator 23 thus preferably provides a binary signal, preferably a digital signal. Figure 4 The preferred digital first comparator output signal 25 of the first comparator 23 is illustrated in the diagram. If the analog-to-digital converter 16 is arranged in the signal path after the ultrasonic transducer 9, instead of as shown... Figure 4 If the first comparator 26 is arranged after amplifier 14 as described above, it can also perform its signal evaluation function in the analog section 35. However, this is generally not meaningful because such an arrangement increases the resolution requirements of the analog-to-digital converter 16. Furthermore, if needed, the computer core 2 can simulate the first comparator 23 as a comparison operation. In the latter two cases, it is preferable that the analog-to-digital converter 16 is positioned appropriately earlier in the signal path. In this regard, the text disclosed herein is again referenced by way of example. Figure 4 In the following text, the implementation of the first comparator 23 is described by way of example, without limiting the technical teachings of this disclosure to implementation of the comparison by analog circuitry as the first comparator 23.

[0078] As long as the amplitude of the electro-ultrasonic received signal 13 of the ultrasonic transducer 9 remains at a significant height, the digital first comparator output signal 25 of the exemplary first comparator 23 typically exhibits digital oscillation. Typically, in this case, the fixed first threshold used by the exemplary first comparator 23 of the ultrasonic sensor system 22 to compare with the transducer voltage amplitude of the electro-ultrasonic received signal 13 of the ultrasonic transducer 9 has a value such that, for example, when the temperature of the ultrasonic sensor system 22 changes, even in the case of a very close object 11 within the vicinity of the ultrasonic sensor 1, the first time point 102 or the third time point 502 of the oscillation ending within the transmission cycle does not shift or only shifts by a few oscillation clock cycles. Therefore, for example, the digital processing and filtering stage 18 and / or the computer core 2 and / or the envelope filter 33 can reliably detect the end of the decay time at the first time point 102 of the first edge change 102 of the first comparator output signal 25 or the third time point 502 of the third edge change 502 of the first comparator output signal 25 within the transmission cycle through digital smoothing and filtering of the first comparator output signal 23. The first time point 102 of the first edge change 102 of the first comparator output signal 25 is typically a first temperature-dependent time difference 101 prior to the second time point 103, at which the envelope signal of the processed digital ultrasonic received signal 34 drops below the second threshold signal 27. However, due to the large amplitude, this second time point 103 is practically unrelated to the feedback effect caused by sound reflections on the ultrasonic transducer 9. The third time point 502 of the third edge change 502 of the first comparator output signal 25 is also prior to the fourth time point 503, when the envelope signal of the processed digital ultrasonic received signal 34 undershoots the second threshold signal 27 via the temperature-dependent second time difference 501, but due to the large amplitude, this third time point 502 is practically unrelated to the feedback effect of sound reflections on the ultrasonic transducer 9.

[0079] The example given here (see Figure 4 In this circuit, the digital envelope filter 33 is not located within the analog amplifier 14, but rather in the received signal path (13, 14, 15, 16, 17, 33, 34, 18, 19, 2) after the analog-to-digital converter 16. Figure 4 In the example, the envelope filter 33 extracts the envelope signal from the digitized ultrasound received signal 17 of the analog-to-digital converter 16. The envelope signal is preferably a part of or a portion of the processed digital ultrasound received signal 34.

[0080] Only after timer 41 has elapsed a corresponding subsequent third time difference, the digital processing and filtering stage 18 or the computer core 2 preferably now allows, for example, the first time point 102 referencing the first edge change 102 of the first comparator output signal 25 or the third time point 502 referencing the third edge change 502 of the first comparator output signal 25, the second comparator output signal 28 to send a signal to the second comparison logic circuit, which performs a function equivalent to the comparison of the second comparator 26, to evaluate the processed digital ultrasound received signal 34 and receive the echo. Timer 41 may also be part of the digital processing and filtering stage 18. Preferably, the computer core 2, by means of... Figure 1 and Figure 4 One or more signal lines are shown to control timer 41. Alternatively, the computer core 2 can implement the functions of timer 41 and / or the second comparison logic circuit 26, for example, through simulation. The second comparison logic circuit 26, which functionally implements the function of the second comparator 26, preferably starts the counting process of the timer clock of timer 41 when a first time point 102 or a third time point 502 is reached.

[0081] The first comparator output signal 25 of the first comparator 23 indicates the start of the decay process of the ultrasonic transducer 9 via a first edge change 102 at a first time point 102 or via a third edge change 502 at a third time point 502. The second comparator output signal 28, which simulates the second comparator logic circuit of the second comparator 26 in a functionally equivalent manner, indicates the end of the decay process of the ultrasonic transducer 9 via a second edge change 103 at a second time point 103 or via a fourth edge change 503 at a fourth time point 503.

[0082] Here, even a small modification can cause the second comparator output signal 28 of the second comparison logic circuit, simulating the second comparator 26, to provide a correction indication for the reflection. For example, the EXOR gate 30, or a functionally equivalent third logic circuit, may sometimes output a signal indicating the end of decay of the oscillating element 8 of the ultrasonic transducer 9. The second comparator output signal 28 and, preferably, the EXOR control signal 32 of the digital processing and filtering stage 18 or the computer core 2, form the preferred input to the EXOR gate 30 or the third logic circuit. The output 31 of the EXOR gate 30 preferably forms the input signal to the digital processing and filtering stage 18.

[0083] For this purpose, EXOR gate 30 or the third logic circuit switches the second comparator output signal 28 to the first logic level. This is preferably completed within a predetermined third time period associated with the first time point 102 or the third time point 502 at the end of the transmission phase of the ultrasonic transducer 9. Thus, the first comparator output signal 25 of the first comparator 26 signals the end of the transmission phase of the ultrasonic transducer 9. The first comparator 23 detects the attenuation of the ultrasonic transducer 9 at the first time point 102 or the third time point 502. The length of this third time period preferably corresponds to the length of the first time difference 101 in the absence of a reflecting object 11. The ultrasonic sensor system 22 preferably determines the duration of the first time difference by means of short ultrasonic pulses in the exemplary compensation measurement 504. This is in Figure 2 and Figure 5 As shown in the figure. Preferably, the length of the third time period does not depend on the length of the second time difference 501. That is, the document proposed herein suggests that, in the exemplary compensation measurement 504, the length of the third time period is determined based on the detected first time difference 101 determined by the ultrasonic sensor system 22 using the short ultrasonic pulse train 504.

[0084] If object 11 is now spatially close to ultrasonic transducer 9, the earlier arrival echo of the earlier arriving reflected ultrasonic pulse train 12 increases the amplitude curve 107 of the envelope within the corresponding time range. However, this now shifts the fourth time point 503 backward in time. Since the short ultrasonic pulse of compensation measurement 504 has a smaller proximity, there exists a range within which the second time point 103 has not yet shifted backward in time. Due to the appropriate design of the EXOR circuit of EXOR gate 30 or a corresponding alternative to the third logic path, the output of EXOR circuit 30 switches the first comparator output signal 25 of the first comparator 23 previously present at the output terminal 31 of EXOR gate 30 to an inverted logic value corresponding to the echo. The surprising finding now disclosed here is that, firstly, as is known in the prior art, the ultrasonic sensor system 22 here is now able to detect object 11 within close range of the ultrasonic sensor system 22, but cannot determine the exact location of object 11. However, by using the value of the first time difference 101 as the task value of the counter of timer 41, this detection is now no longer dependent on temperature and is therefore useful. When the counter value of timer 41 reaches the load value, timer 41 drives the EXOR gate 30 or the EXOR control signal 32 of the third logic circuit. Thus, the digital processing and filtering stage 18 detects the presence of object 11 in the near field. Using this proposed method, the exact location of object 11 at close range cannot be determined. However, for most applications, it is perfectly sufficient to have detected the presence of object 11 at this close range. These measures have so far improved the receiving behavior of the ultrasonic sensor system 22 at close range.

[0085] However, it has been further shown that the digital processing and filtering stage 18 or the computer core 2 should perform optimized adjustments to the filtering of the envelope signal of the processed digital ultrasonic received signal 34 and the comparator output signals 28, 25 in parallel with the measures described above, in order to obtain practically useful results in the automotive field. These two measures, namely one described above and one described below, themselves produce improvements. However, based on experience, these two measures are generally insufficient on their own for automotive applications.

[0086] The following sections relate to the parameterization of the envelope filter 33, particularly for the timing of the primary ultrasound measurement 505. In contrast to the prior art, according to the proposal, one or more parameters of the envelope filter 33 depend on the values ​​of a first time point 102 and / or a second time point 103 and / or a first time difference 101. Preferably, the values ​​of the first time point 102 and / or the second time point 103 and / or the first time difference 101 are determined by the ultrasound sensor system 22 by means of a compensation measurement 504, preferably occurring exactly in time.

[0087] Therefore, the invention further proposes that the ultrasonic sensor system 22 employs a method for adjusting the parameters of the digital envelope filter 33 to filter the digitized ultrasonic received signal 17 into an envelope signal of the processed digital ultrasonic received signal 34. For the purposes of the invention, the digital envelope filter 33 preferably has bandpass characteristics. The proposed method again determines a second time point 103, at which the instantaneous value of the amplitude of the envelope signal of the processed digital ultrasonic received signal 34 is lower than the second threshold 105 of the second threshold signal 27. The invention now proposes that from this specific second time point 103, for example, the computer core 2 or the digital processing and filtering stage 18 switches the bandpass characteristics of the digital envelope filter 33, such that the bandpass characteristics of the envelope filter 33 become narrower. This decrease in the instantaneous value of the envelope signal of the processed digital ultrasonic received signal 34 below the second threshold 105 of the second threshold signal 27 occurs at the second time point 103 during the compensation measurement 504 or at a fourth time point 503 during the main ultrasonic measurement 505. Preferably, the bandpass characteristic of the envelope filter 33 is narrower within a time range exactly before the switching at the second time point 103 or the fourth time point 503. At the end of the ultrasonic pulse cycle, the digital processing and filtering stage 18 and / or the computer core 2 preferably resets the relevant parameters of the envelope filter 33 and / or amplifier 14 and / or other device parts of the ultrasonic sensor system 22 and / or ultrasonic sensor 1 to the initial values ​​intended for the start of the ultrasonic pulse cycle. This generally does not apply to the length of the detected first time difference 101, which is preferably maintained until the next measurement of the duration of the first time difference 101 by means of a short ultrasonic pulse in the compensation measurement 504. Subsequently, the value of the envelope signal of the envelope filter 33 decreases slowly. With such a second threshold signal 27, a near object 11 with a so-called "near echo" arriving shortly after the ultrasonic pulse train is emitted no longer causes the envelope signal of the processed digital ultrasonic received signal 34 to drop below the second threshold 105 of the second threshold signal 27. Then, the ultrasonic sensor system 22 may no longer need to determine the fourth time point 503. Preferably, the digital processing and filtering stage 18 and / or the computer core 2 and / or the ultrasonic sensor system 22 and / or the ultrasonic sensor 1 then use the value of the transmission period corresponding to the distance between the two pulses as a substitute value. Preferably, they then use this value as a substitute value for the second time difference 501. However, a near-field object 11 with a so-called "very close echo" arriving shortly after the transmission of the short ultrasonic pulse train 10 can also cause the second threshold 105 of the second threshold signal 27 at the first time point 102 to strike later in time using the envelope signal of the processed digital ultrasonic receiving signal 34.The reason is that the oscillation of the ultrasonic transducer 9 has not yet ended, and the object 11 is so close that the short ultrasonic pulse train of the compensation measurement 504 is also interfered with.

[0088] This paper proposes that the digital processing and filtering stage 18 or computer core 2 progressively switches the digital envelope filter 33 during the transmission cycle. Preferably, the envelope filter 33 is the envelope filter of the digital section 35. In extreme cases, this switching can be accomplished in such a way that the digital processing and filtering stage 18 or computer core 2 continuously readjusts the analog components of the envelope filter 33 used to determine the characteristic frequency by sending signals to the envelope filter 33 via control lines not shown in the figure. The digital processing and filtering stage 18 or computer core 2 preferably performs the switching or readjustment of the digital envelope filter 33 according to the time elapsed since the first time point 102, and the digital envelope filter 33 is typically a bandpass filter. Generally, the switching or readjustment involves the characteristic frequency and / or amplitude of the transfer function of the digital envelope filter 33. Various possibilities for defining the time value of the past time period are possible:

[0089] The elapsed time period can be the duration of the time period that begins when the drive stage of the ultrasonic transducer 9 is turned off at the end of the transmission phase at the second time point 103 or the fourth time point 503. Preferably, the digital processing and filtering stage 18 or the computer core 2 switches and / or readjusts the parameters of the digital envelope filter 33 according to the time from the second time point 103 or from the fourth time point 503.

[0090] Alternatively, or in parallel over time, the digital processing and filtering stage 18 or the computer core 2 can switch and / or readjust the parameters of the digital envelope filter 33 based on a time from the first time point 102 already discussed or from the third time point 503, from which point the digital first comparator output signal 25 of the first comparator 23 no longer exhibits oscillation.

[0091] Alternatively, or in parallel over time, the digital processing and filtering stage 18 or the computer core 2 may also switch and / or readjust the parameters of the digital envelope filter 33 based on the envelope signal of the processed digital ultrasound received signal 34.

[0092] In the latter case, gradual switching may require additional comparators and / or comparison logic circuits and / or functionally equivalent comparison operations or devices that utilize corresponding additional switching threshold signals to perform these switching based on corresponding additional switching thresholds.

[0093] Preferably, the threshold generation device 29 generates threshold signals 24 and 27, as well as other possible threshold signals. Preferably, the digital processing and filtering stage 18 and / or the computer core 2 controls the threshold generation device 29, the generation of threshold signals 24 and 27, and the generation of any other threshold signals by the threshold generation device 29. Preferably, the threshold generation device 29 generates threshold signals 24 and 27, and, if applicable, generates other threshold signals based on time since the first time point 102, time since the third time point 502, and / or time since the second time point 103 or the fourth time point 503, and / or based on the first time difference 101.

[0094] As a result, a faster falling edge was obtained in the amplitude curve 107 of the envelope signal of the processed digital ultrasonic received signal 34, which enabled the ultrasonic sensor system 22 to detect the reflection of the object 11 at close range earlier.

[0095] Adapting to the typical envelope curve of the system, 107 of the amplitude curve of the envelope signal of the processed digital ultrasound received signal 34, a second threshold signal 27 that decreases exponentially over time can now be additionally specified. In this case, the second comparison logic circuitry, preferably corresponding to the function of the second comparator 26, again detects, for example, that the amplitude curve 107 of the envelope signal of the processed digital ultrasound received signal 34 is below the second threshold signal 27. This occurs at a second time point 103 or a fourth time point 503. With a third time interval delayed compared to the first time point 102 within the transmission period, the exponential decay of the value of the second threshold signal 27 begins, from a predetermined or determined first time constant τ1 to a predetermined or otherwise determined remaining threshold. Preferably, the duration of the third time interval depends on the duration of the first time difference 101 or the difference 601 between the second time difference 501 and the first time difference 101.

[0096] Therefore, in one aspect, the basic method is an evaluation method for the electro-ultrasonic received signal 13 of the piezoelectric ultrasonic transducer 9. Here, in a first step, a first comparator 23 or a functionally equivalent device compares the instantaneous value of the electro-ultrasonic received signal 13 of the ultrasonic transducer 9, or the signal derived from the electro-ultrasonic received signal 13, with a first threshold, and forms a digital first comparator output signal 25, etc., based on the result. Preferably, in a second step of the basic method, an amplifier 14 forms an amplified ultrasonic electro-received signal 15, while simultaneously amplifying and filtering the electro-ultrasonic received signal 13. An analog-to-digital converter 16 preferably converts the amplified ultrasonic electro-received signal 15 into a digital ultrasonic received signal 17. An envelope filter 33 typically forms a processed digital ultrasonic received signal 34 from the digital ultrasonic received signal 17. The processed digital ultrasonic received signal 34 preferably includes an envelope signal, or an envelope signal. Preferably, the filtering parameters in the envelope filter 33 are thus designed to be switchable or controllable. In the next step of the basic method, the threshold generation device 29 forms a preferred analog first threshold signal 24 and a preferred digital second threshold signal 27, as well as optional other threshold signals. Specifically, the threshold generation device 29 can generate the threshold signals 24 and 27, and the other threshold signals, by filtering from the envelope signal of the processed digital ultrasound received signal 34. Furthermore, the threshold generation device 29 can generate the threshold signals 24 and 27, and the other threshold signals, by filtering from the electro-ultrasound received signal 13 of the ultrasound transducer 9. Typically, in this case, the second threshold signal 27 is compared to the first threshold signal 24 such that the first comparator 23 switches at a higher amplitude in the electro-ultrasound received signal 13 compared to the second comparison logic of the analog second comparator 26. Then, the second comparison logic circuit of the analog second comparator 26 compares the amplitude curve 107 of the envelope signal of the processed digital ultrasound received signal 34 with the second threshold 105 of the second threshold signal 27. The output signal 28 of the second comparison logic circuit of the analog second comparator 26 reproduces the detected echo. At close range, the output signal 31 of the EXOR gate 30 reproduces the detected echo, and the signal at close range only indicates that the object is within close range. Therefore, if needed, the computer core 2 can directly signal the output signal 28 of the second comparison logic circuit of the analog second comparator 26 or the output signal 31 of the EXOR gate 30 to the control unit 21. According to the invention, it is particularly important to determine the first time point 102 or the third time point 503 of the attenuation of the ultrasonic transducer 9. This is accomplished by detecting the first time point 102 or the third time point 503, at which time point 102 or the third time point 503, the output 25 of the first comparator 23 no longer displays a signal after the control of the ultrasonic transducer 9 has been turned off. This event at the first time point 102 or the third time point 503 typically triggers the timer 41.Computer core 2 and / or digital processing and filtering stage 18 stop timer 41 at the end of the transmission cycle, and then preferably reset timer 41 to a predetermined value.

[0097] According to the example, within a predetermined first time period Δt1 after the ultrasonic transducer (TR) oscillates to a corresponding other logic value at a first time point 102 or a third time point 503, the timer 41 switches the second output signal 28 of the second comparison logic of the analog second comparator 26. Thus, for example, according to the system design, from 1 to 0, and vice versa.

[0098] The device according to the invention, in the form of an ultrasonic sensor system 22, corresponds to the method according to the invention described above, and the device performs the corresponding method at least in part. The device according to the invention is used to detect the presence of an object at close range in an ultrasonic measurement system according to the invention (particularly in a car). It has an ultrasonic transducer 9, the voltage signal of which is detected. An envelope generating device, as part of the digital envelope filter 33 of the ultrasonic sensor 1 of the device, determines the envelope signal of the processed digital ultrasonic received signal 34 based on the digitized ultrasonic received signal 17 of the ultrasonic transducer 9. A threshold generator 29, also as part of the device, generates a second threshold signal 27 having a second threshold 105. Furthermore, the device includes a second logic circuit simulating the second comparator 26. The second logic circuit compares the second threshold 105 of the second threshold signal 24 with the value of the amplitude curve 107 of the envelope signal of the processed digital ultrasonic received signal 34. As a result of this comparison, the second logic circuit generates a second comparator output signal 28. Typically, the second comparator output signal 28 is thus inverted or set to a fixed value by a control signal via a third logic circuit (e.g., EXOR gate 30), particularly according to logic 1 of the example. Furthermore, the device typically includes a first comparator 23 that compares the value of the electro-ultrasound received signal 13 of the ultrasonic transducer 9 with a first threshold of a first threshold signal 24, wherein the first threshold of the first threshold signal 24 is selected compared to a second threshold 105 of a second threshold signal 27, such that the first comparator 23 switches at a higher value of the electro-ultrasound received signal 13 of the ultrasonic transducer 9 compared to a second logic circuit analog to a second comparator 26. As previously described, the device includes a timing detection device that determines a first time point 102 or a third time point 502 after the active drive of the ultrasonic transducer 9 has ended, at which time the value of the electro-ultrasound received signal 13 of the ultrasonic transducer 9 is no longer sufficient to cause the first comparator 23 to switch.

[0099] The timing detection device starts timer 41 by means of a start signal. Timer 41 is part of the device. During a first time period (Δt1), timer 41 switches the second comparator output signal 28 of the second logic circuit of the analog second comparator 26 to a state corresponding to the logic value of a signal without reflection by means of a control signal 32 detected from a first time point 102 or a third time point 502. Preferably, the switching device 30 is a third logic circuit or a functionally equivalent device. Preferably, the computer core 2 and / or the digital processing and filtering stage 18 controls this switching via control signaling 32. The third logic circuit may include an EXOR gate 30. In this case, the EXOR control signal 32 can then send signaling to the EXOR gate 30.

[0100] Furthermore, the proposed device preferably has another feature that itself leads to improvements beyond existing technologies, but which itself does not yet meet the modern requirements of the automotive market. Such a device for detecting the presence of an object within close range of the ultrasonic sensor system 22 also includes an ultrasonic transducer 9, whose electro-ultrasonic received signal 13 is detected. Preferably, the device includes an envelope generating device 33, which generates a processed digital ultrasonic received signal 34 from the digitized ultrasonic received signal 17, the processed digital ultrasonic received signal 34 typically including a digital envelope signal. Therefore, the envelope generating device 33 preferably includes a controllable envelope filter 33. The proposed device also includes: a threshold generating device 29, which preferably generates a digital second threshold signal 27 having a second threshold 105; and a second logic circuit that simulates the function of a second comparator 28. The second logic circuit compares the second threshold signal 27 with the amplitude response 107 of the envelope signal of the processed digital ultrasonic received signal 34 and generates a second comparator output signal 28 of the second logic circuit 26. During device operation, the computer core 2 and / or the digital processing and filtering stage 18 change at least one characteristic frequency of the controllable envelope filter 33 at at least one point in time according to the second comparator output signal 28 of the second comparator 26 or in relation to the second comparator output signal 28 of the second comparator 26.

[0101] In another embodiment, the device further includes a first comparator 23 that compares the electro-ultrasound received signal 13 of the ultrasonic transducer 9 with a first threshold of a first threshold signal 24, wherein, preferably, the first threshold of the first threshold signal 24 is also selected compared with a second threshold 105 of a second threshold signal 27, such that the first comparator 23 switches at a higher value of the electro-ultrasound received signal 13 of the ultrasonic transducer 9 compared with a second comparator 26. For timing control, the device also preferably includes the timing determination device. This determines a first time point 102 or a third time point 502 after the end of the active control time of the ultrasonic transducer 9, from which the value of the electro-ultrasound received signal 13 of the ultrasonic transducer 9 is no longer sufficient to cause the first comparator 23 to switch. Thus, a fixed time reference point is created, and the control task can now be enabled. Based on the elapsed time associated with the first time point 102 or the third time point 502, the control task of the envelope filter 33 and the threshold generation device 29 can now be performed in a time-dependent manner. For this purpose, the device typically has a timer 41. Timer 41 may be part of a digital processing and filtering stage 18, which preferably changes the filtering characteristics of the envelope filter 33 of the envelope generation device in amplifier 14 at least twice, after at least a third time period (Δt3) and at least a fourth time period (Δt4) with respect to the first time point 102 and the third time point 502, respectively. Of course, it is conceivable that such changes will be made a very large number of times, resulting in a quasi-continuous change in the parameters of the second threshold signal 27 and / or the envelope filter starting from the first time point 102 or the third time point 502. Figure 4 In the example, timer 41 is preferably a digital device and / or logic circuit that generates a digital signal, for example, representing a value of the duration of elapsed time that is linearly or nonlinearly but strictly monotonically decreasing or strictly monotonically increasing over time, and continuously controls one or more parameters of the second threshold signal 24 and / or the envelope filter 33.

[0102] In the case of discrete control, for example by a digital timer 41, the timer 41 can also control the threshold generating device 29 after at least a fifth time period (Δt5) related to the first time point 102 or the third time point 502 in such a way that the second threshold 105 of the second threshold signal decreases exponentially from the first time point 102 or the third time point 502 to the remaining threshold with a first time constant τ1. Figure 1 and Figure 2 For clarity, one or more control lines used by timer 41 to control threshold generation device 29 are not shown. These lines start at timer 41 and end at threshold generation device 29.

[0103] The analog ultrasonic transmitter stage 6 of the ultrasonic sensor 1 typically controls the ultrasonic transducer 9 using the control signal 7 at the beginning of the transmission cycle during the transmission phase. After the transmission phase, the analog ultrasonic transmitter stage 6 controls the ultrasonic transducer 9 during the braking phase, causing it to lose as much energy as possible in a short time to oscillate as quickly as possible. After the braking phase ends, the ultrasonic transducer 9 continues to oscillate during the decay phase. Preferably, after the ultrasonic transducer 9 has already oscillated during the oscillation phase, the remaining portion of the transmission cycle of the analog ultrasonic transmitter stage 6 during the receiving phase is inactive. The remaining portion of the transmission cycle after the transmission and deceleration phases is divided into a steady-state period and a receiving period. The transmission cycle typically repeats periodically. The first comparator 23 compares the value of the electro-ultrasonic received signal 13 of the ultrasonic transducer 9 with a first threshold signal 24, which is typically predetermined by the threshold generating device 29. The first threshold is selected such that it is more effective than the second threshold 105 of the second threshold signal 27. Preferably, the first comparator output signal 25 of the first comparator 23 is evaluated by a time-point detection device. The time-point detection device is preferably part of the digital processing and filtering stage 18. The computer core 2 can also be used as the time-point detection device. After the active control of the ultrasonic transducer 9 ends, the time-point detection device determines a first time point 102 or a third time point 502, after which the value of the electro-ultrasonic receiving signal 13 of the ultrasonic transducer 9 is no longer sufficient to switch the first comparator 23. Typically, the first time point 102 or the third time point 502 exists at the output of the time-point detection device in the form of appropriate corresponding signals. This signal typically starts the timer 41. Figure 4In the example, the digital processing and filtering stage 18 performs the function of the time detection device. Timer 41 may be part of the digital processing and filtering stage 18. The computer core 2 may also operate as timer 41, or include such timer 41. Therefore, preferably, timer 41 is started when the first time point 102 or the third time point 502 is reached within the transmission cycle. The end of the transmission cycle or the start of the transmission cycle preferably resets timer 41. Timer 41 is typically started when the analog ultrasonic emission stage 6 of the ultrasonic sensor 1 is turned off. In the first embodiment, within the first time period (Δt1), starting from the first time point 102 or the third time point 502 in the corresponding transmission cycle, by means of logic control signal 32 and by means of third control logic circuitry 30, timer 41 typically switches the second comparator output signal 28 of the second comparator 26 to a state corresponding to the logic value of the second comparator output signal 28 of the second comparator 26 when there is no reflection. In a second, less preferred embodiment, timer 41, via another control line, changes the filtering characteristics of the envelope filter 33 of the envelope generating device at least twice within a transmission cycle following at least a third time period (Δt3) and at least a fourth time period (Δt4) with respect to the first time point 102 and the third time point 502, respectively. It is also conceivable to have a quasi-continuous or continuous change with a function of change starting from a fifth time point, which is shifted by a third time period Δt3 relative to the first time point 102 or the third time point 502. Particularly preferred is that the filtering characteristics of the envelope filter 33 of the envelope generating device are changed at four time points following the first time point 102 or the third time point 502. However, compared to the control of the filtering characteristics by timer 41, it is preferred to control the envelope filter by means of filter control and based on the second comparator output signal 28 of the second comparator 26. Therefore, filter control is preferably part of the digital processing and filtering stage 18. The computer core 2 can also be used for filter control. In the third embodiment, after at least a fifth time period (Δt5) relative to the first time point 102 or the third time point 502 of the transmission period, the timer 41 preferably changes the threshold generation of the threshold signals 24 and / or 27 and possibly other threshold signals by means of the threshold generation device 29 in such a way that the second threshold 105 of the second threshold signal 27 generated by the threshold generation device 29 decreases exponentially from that time point (Δt5) to the remaining threshold with a first time constant τ1.

[0104] It will be apparent to those skilled in the art that the functionality shown in this block diagram can also largely function as software on a signal processor. In this respect, one or more components of this block diagram can also be combined into a single device in an implementation.

[0105] Because the energy of a single pulse echo, i.e., the energy of a short ultrasonic pulse train 504, is very low, the attenuation process is almost undisturbed. In the case of very close objects 11, the situation can be reversed by the reciprocating wave, thus meaningfully allowing negative time differences or time ratios smaller than a certain threshold when necessary.

[0106] The determination of the first threshold and the determination of the second threshold 105 of the second threshold signal 27 (if applicable) are generally temperature-related.

[0107] In summary, the solution of this invention is based on two fundamental insights:

[0108] a) The first time difference 101 of the ultrasonic pulse train 10 with one ultrasonic pulse is approximately equal in time to the second time difference 501 of the ultrasonic pulse train 10 with 16 ultrasonic pulses.

[0109] b) The ultrasonic pulse train 10 with ultrasonic pulse emission can be assumed to be not interfered with by the ultrasonic pulse train 12 reflected by the object 11 at close range of the ultrasonic sensor 1.

[0110] The proposed solution is that the individually emitted ultrasonic pulse train 10 from time to time consists of only a few ultrasonic pulses, preferably only one. In the special compensation measurement 504, the ultrasonic sensor 1 uses these short emitted ultrasonic pulses 10 to detect the first time difference 101. However, during the main ultrasonic measurement 505, the ultrasonic sensor 1 typically performs distance measurements using longer emitted ultrasonic pulse trains 10. This provides a greater range for distance measurements by the ultrasonic sensor. However, for objects 11 within close range of the ultrasonic sensor 1, this range is not necessary at all, and is even counterproductive, as it increases the blind zone where the ultrasonic sensor 1 cannot detect anything.

[0111] By using a longer emitted ultrasonic pulse train 10, the ultrasonic sensor 1 can detect a second time difference 501, through which an inference can be made about an object 11 within close proximity of the ultrasonic sensor 1. For example, the ultrasonic sensor 1 can normalize the second time difference 501 to the length of a first time difference 101, thereby assessing their relationship to each other. Therefore, the ultrasonic sensor 1 can correct for temperature fluctuations.

[0112] By using an additional compensation measurement 504, preferably employing only one ultrasonic pulse in the transmitted ultrasonic pulse train 10, a reference in the form of a measurement of the first time difference 101 can be generated. The computer core 2 of the ultrasonic sensor 1 calculates this measurement using the measurement of the subsequently performed ultrasonic master measurement 505, and thus generates the compensation. Therefore, the measurement sequence is preferably as follows: a first I-pulse measurement occurs, the compensation measurement 504 is performed, then preferably a normal measurement is performed, followed by the ultrasonic master measurement 505. However, this sequence is preferred but not explicitly mandatory. Performing the compensation measurement 504 periodically is sufficient. In a less preferred embodiment, the ultrasonic sensor 1 can also store the duration values ​​of the second time difference 501 previously measured using one or more ultrasonic master measurements 505, and then retrospectively evaluate them using only the first time difference 101 after the compensation measurement 504. This possible process is not recommended by the invention presented herein.

[0113] advantage

[0114] The presence of an object 11 within close proximity of the ultrasonic sensor 1 can be detected using the method and apparatus described herein. However, the advantages are not limited to this. Due to the process presented herein, the measurement method is significantly less dependent on parameters and temperature. Attached Figure Description

[0115] Figure 1 An exemplary device according to this solution is shown.

[0116] Figure 2 An exemplary time process of the amplitude 107 of the envelope signal of an ultrasonic pulse train is shown.

[0117] Figure 3 This illustrates what is understood as presented in the technical teachings of this article. Figure 1 The temperature dependence of the duration of the first time difference 101 on temperature.

[0118] Figure 4 To a large extent correspond to Figure 1 However, the envelope filter 33 is now unlike... Figure 1 Instead of being part of amplifier 14, it is designed and arranged as a digital envelope filter 33 in the signal path following analog-to-digital converter 16.

[0119] Figure 5 Corresponding to Figure 1 However, timer 41 no longer inverts the second comparator output signal 28.

[0120] Figure 6 Corresponding to Figure 4Therefore, timer 41 no longer inverts the second comparator output signal 28, and the digital processing and filtering stage 18 and / or computer core 2 now preferably evaluate the second comparator output signal 28 directly.

[0121] Figure 7 An exemplary time sequence is shown for the amplitude curve 107 of the envelope signal for the first short ultrasound pulse train 504 and the subsequent long ultrasound pulse train 505.

[0122] Figure 8 This illustrates what is understood in the technical teachings presented in this article. Figure 1 and Figures 4 to 6 The temperature dependence of the first time difference 101 on temperature, and the understanding gained in the technical teachings of this paper. Figure 1 and Figures 4 to 6 The temperature dependence of the second time difference 501 on temperature.

[0123] Figure 9 The first exemplary order of the exemplary measurement order is shown.

[0124] Figure 10 A second exemplary order of measurement is shown.

[0125] Figure 11 Corresponding to Figure 5 ,Apart from Figure 11 There is no timer 41.

[0126] Figure 12 Corresponding to Figure 3 ,Apart from Figure 12 There is no timer 41.

[0127] Figure 13 Corresponding to Figure 9 The difference is that, after determining in step 903 that an object 11 is present in the vicinity of the ultrasonic sensor 1, the ultrasonic sensor 1 now switches to the main ultrasonic measurement 505 using a short ultrasonic pulse 10 until the object 11 disappears from the vicinity of the ultrasonic sensor 1.

[0128] Figure 14 Corresponding to Figure 10 The difference is that, after determining in step 6 1005 that an object 11 is present in the vicinity of ultrasonic sensor 1, ultrasonic sensor 1 now switches to ultrasonic master measurement 505 by emitting short ultrasonic pulses 10 until the object 11 disappears from the vicinity of ultrasonic sensor 1. Detailed Implementation

[0129] Figure 1An exemplary device according to this invention is shown. This device represents an ultrasonic sensor system 22. The ultrasonic sensor system 22 includes a control unit 21 and one or more ultrasonic sensors 1. Each ultrasonic sensor 1 includes an evaluation circuit 37. The evaluation circuit 37 includes a computer core 2. A data bus 20 connects the computer core 2 of the ultrasonic sensor 1 to the control unit 21 of the ultrasonic sensor system 22. The computer core 2 generates control signals 4 for a digital ultrasonic pulse train generator 3 of the ultrasonic sensor 1. If needed, the computer core 2 can conveniently query the status information of the digital ultrasonic pulse train generator 3 of the ultrasonic sensor 1 via the internal data bus of the internal control circuit 37. The digital ultrasonic pulse train generator 3 of the ultrasonic sensor 1 generates digital ultrasonic transmission signals 5. Preferably, the analog ultrasonic transmission stage 6 of the ultrasonic sensor 1 drives the piezoelectric oscillating element 8 of the ultrasonic transducer 9 by means of a drive signal 7 from the ultrasonic sensor 1. Along with the control signal for the digital ultrasonic pulse train generator 3 of the ultrasonic sensor 1, the digital ultrasonic transmission signal 5, and the drive signal 7 of the ultrasonic sensor 1, the digital ultrasonic pulse train generator 3 of the ultrasonic sensor 1 and the ultrasonic pulse train generator 3 of the ultrasonic sensor 1 are generally part of the evaluation circuit 37. During the transmission phase, the control signal 7 typically excites the oscillating element 8 of the ultrasonic transducer 9 to an initial mechanical vibration, which the oscillating element 8 then transmits to the surrounding air and radiates as an emitted ultrasonic pulse train 10.

[0130] Preferably, the drive signal 7 attenuates the first mechanical vibration of the oscillating element 8 of the ultrasonic transducer 9 in a subsequent decay phase in time.

[0131] In the subsequent receiving phase, the reflected ultrasonic pulse train 12, reflected by object 11, excites the oscillating element 8 of the ultrasonic transducer 9 to undergo a second mechanical vibration. Due to its typically present piezoelectric properties, the oscillating element 8 converts these second mechanical vibrations into an electro-ultrasonic receiving signal 13. Amplifier 14 converts the electro-ultrasonic receiving signal 13 into an amplified electro-ultrasonic receiving signal 15. Preferably, in Figure 1 In this example, amplifier 14 includes an envelope generator that includes an envelope filter. For example, the envelope filter generates an envelope signal based on a typically amplified electro-ultrasound received signal 13, which is preferably a portion of an amplified electro-ultrasound received signal 15. Therefore, the amplified electro-ultrasound received signal 15 can also be a signal bundle in the literal sense presented herein. Typically, evaluation circuitry 37 includes the electro-ultrasound received signal 13, amplifier 14 with an envelope filter, and amplified electro-ultrasound received signal 15.

[0132] For example, the threshold generation device 29 generates a first threshold signal 24, which signals the first threshold to the first comparator 23. Preferably, the evaluation circuit 37 includes the threshold generation device 29, the first threshold signal 24, and the first comparator 23.

[0133] The first comparator 23 or a functionally equivalent sub-device of the evaluation circuit 37 compares the first threshold signal 24, represented by a signal, with the value of the electro-ultrasound received signal 13 or a signal derived therefrom, and generates a first comparator output signal 25 based on the comparison result. The evaluation circuit 37 typically includes the first comparator output signal 25.

[0134] Preferably, the analog-to-digital converter 16 converts the amplified electro-ultrasound received signal 15 into a digitized ultrasound received signal 17. Figure 1 In the example, since the amplified electro-ultrasound received signal 15 includes an envelope signal or an envelope signal, the analog-to-digital converter 16 preferably converts the analog envelope signal in the amplified electro-ultrasound received signal 15 into a digitized envelope signal. Thus, the digitized envelope signal is preferably a digitized sampling sequence of the analog envelope signal in the amplified electro-ultrasound received signal 15. Preferably, this digitized sampling sequence of the analog envelope signal is a sampling sequence in which the analog-to-digital converter 16 determines the values ​​of the analog envelope signal present at these sampling times in the amplified electro-ultrasound received signal 15 at substantially equidistant sampling times. The evaluation circuit 37 typically includes the analog-to-digital converter 16.

[0135] Evaluation circuit 37 uses first comparator 23 and / or a functionally equivalent sub-device of evaluation circuit 37 to determine a first time point 102 of the first edge change 102 of the first comparator output signal 25. This first time point 102 of the first edge change 102 of the first comparator output signal 25 represents the moment when evaluation circuit 37 assumes the start of the time reception phase and the end of the time decay phase. Therefore, the first edge change 102 of the first comparator output signal 25 signals the start of the time reception phase and the end of the time stabilization phase.

[0136] The technical teachings presented herein propose that the ultrasonic sensor 1 first emits one or more short ultrasonic pulse trains 504, and then emits one or more long ultrasonic pulse trains 505. Preferably, the ultrasonic sensor 1 detects a first time point 102 by means of the short ultrasonic pulse trains 504. Corresponding to the first time point 102 determined by means of the one or more short ultrasonic pulse trains 504 is a third time point 502, which is determined by the ultrasonic sensor 1 in an analog manner by means of the one or more long ultrasonic pulse trains 505.

[0137] For example, the threshold generation device 29 generates a second threshold signal 27, which signals the second threshold to the second comparator 26. Preferably, the evaluation circuit 37 includes the second threshold signal 27 and the second comparator 26.

[0138] The second comparator 26 or a functionally equivalent sub-device of the evaluation circuit 37 compares this second threshold signal 27, represented by a signal, with the value of the amplified electro-ultrasound received signal 15 or a signal derived therefrom, and generates a second comparator output signal 28 in response to the comparison result. The evaluation circuit 37 typically includes the second comparator output signal 28.

[0139] Using a second comparator 26 and / or a functionally equivalent sub-device, evaluation circuit 37 determines a second time point 103 of the second edge change 103 of the second comparator output signal 28. This second time point 103 of the second edge change 103 of the second comparator output signal 28 represents the time point at which the evaluation circuit 37 assumes the arrival of the reflected ultrasonic pulse train 12 reflected from object 11. Therefore, for the purposes of this literature, the second edge change 103 of the second comparator output signal 28 signals the time point of the object echo from object 11.

[0140] The technical teachings of the literature presented herein suggest that the ultrasonic sensor 1 first emits one or more short ultrasonic pulse trains 504, and then emits one or more long ultrasonic pulse trains 505. Preferably, the ultrasonic sensor 1 detects a second time point 103 by means of the short ultrasonic pulse trains 504. Corresponding to the second time point 103 determined by means of the one or more short ultrasonic pulse trains 504 is a fourth time point 503, which is determined by the ultrasonic sensor 1 in an analog manner by means of the one or more long ultrasonic pulse trains 505.

[0141] Just after the decay time at the first time point 102 or the third time point 502 has ended, since the oscillation element 8 of the ultrasonic transducer 9 has not yet fully decayed, the value of the envelope signal of the amplified electro-ultrasonic receiving signal 15 is not lower than the second threshold of the second threshold signal 27.

[0142] The detailed explanation of the proposed scheme shows that, in the absence of a reflective object 11 within close range of the ultrasonic sensor 1, the first time difference 101 between the first time point 102 and the second time point 103 is numerically equal to the second time difference 501 between the third time point 502 of the third edge change 502 of the first comparator output signal 25 and the subsequent fourth time point 503 of the fourth edge change of the second comparator output signal 28.

[0143] The detailed explanation of the proposed scheme also shows that when there is a reflective object 11 in the vicinity of the ultrasonic sensor 1, the first time difference 101 between the first time point 102 and the second time point 103 is numerically smaller than the second time difference 501 between the third time point 502 of the third edge change 502 of the first comparator output signal 25 and the subsequent fourth time point 503 of the fourth edge change of the second comparator output signal 28.

[0144] Evaluation circuit 37 includes a digital processing and filtering stage 18. Preferably, the digital processing and filtering stage 18 evaluates the digitized ultrasonic received signal 17 and generates a filtered ultrasonic received signal 19 and any other data and / or signals that may be present. Preferably, the digital processing and filtering stage 18 generates the filtered ultrasonic received signal 19 and any other data and / or signals available to the computer core 2 for forwarding to the control unit 21 of the ultrasonic sensor system 22 and / or for further processing and / or compression.

[0145] Preferably, the computer core 2 and / or the digital processing and filtering stage 18 determines one or more first time differences 101 between a corresponding first time point 102 and a corresponding second time point 103 by means of one or more short ultrasound pulse trains 504, the one or more first time differences 101 being used for measurement using the corresponding short ultrasound pulse trains 504. Preferably, the computer core 2 and / or the digital processing and filtering stage 18 determines the average first time difference 101 from the plurality of first time differences 101, for example, by averaging.

[0146] Preferably, the computer core 2 and / or the digital processing and filtering stage 18 starts timer 41 at a third time point 502 during measurement using a long ultrasonic pulse train 505. Timer 41 typically counts time values ​​using a counting clock. If the time value of timer 41 reaches the value of a first time difference 101 or the average of the first time difference 101 plus a small predetermined tolerance value, timer 41 inverts the second comparator output signal 28 by means of a functionally equivalent sub-device of EXOR circuit 30 or evaluation circuit 37. Preferably, within a small time tolerance window near the time when the time value of timer 41 reaches the value of the first time difference 101 or the average of the first time difference 101, the functionally equivalent sub-device of EXOR circuit 30 or evaluation circuit 37 blocks signaling via the second comparator output signal 28 to suppress jitter and noise in the second comparator output signal 28. In this respect, the EXOR function of EXOR circuit 30 is an idealized simplified representation, but will not hinder those skilled in the art. The functionally equivalent sub-device of EXOR circuit 30 or evaluation circuit 37 is part of evaluation circuit 37.

[0147] The functionally equivalent sub-device of EXOR circuit 30 or evaluation circuit 37 generates the output signal 31 of EXOR gate 30.

[0148] Computer core 2 and / or digital processing and filtering stage 18 evaluate the output signal 31 of EXOR gate 30 and / or the output signal 25 of the first comparator and / or the time value of timer 41, and preferably control timer 41 accordingly. By means of this evaluation of the output signal 31 of EXOR gate 30 and / or the output signal 25 of the first comparator, computer core 2 and / or digital processing and filtering stage 18 determine a first time point 102 and a second time point 103, and, if necessary, determine a third time point 502 and a fourth time point 503 based on these first time differences 101 and, if necessary, a second time difference 501.

[0149] Preferably, the computer core 2 and / or timer 41 and / or digital processing and filtering stage 18 control the parameters of amplifier 14 and the envelope filter contained therein, as well as threshold generation device 29, according to the time value of timer 41. Therefore, in Figure 1 Two signal lines are shown. Instead of special signal lines, for example, a common internal data bus could be considered to adjust and / or change the parameters of the device components of the evaluation circuit 37 via the computer core 2 and / or other device components.

[0150] The controlled parameters may be the filter frequency of the envelope filter and / or the gain of the amplifier 14 and / or the first threshold of the first threshold signal 24 and / or the second threshold of the second threshold signal 27, which can be selectively changed over time during the transmission period.

[0151] Compared to the first time difference 101, the presence of an object 11 in close proximity to the ultrasonic sensor 1 causes an increase in the duration of the second time difference 501.

[0152] Therefore, the computer core 2 and / or the digital processing and filtering stage 18 can infer the object 11 within the vicinity of the ultrasonic sensor 1 from the first time difference 101 relative to the second time difference 501 in four different ways:

[0153] i. If the difference between the value of the first time difference 101 and the value of the second time difference 501 is less than (since it is negative) the minimum time difference threshold, then the computer core 2 and / or the digital processing and filtering stage 18 can infer the presence of an object 11 in the vicinity of the ultrasonic sensor 1.

[0154] ii. If the difference between the value of the second time difference 501 and the value of the first time difference 101 is greater than (since it is positive) the maximum time difference threshold, then the computer core 2 and / or the digital processing and filtering stage 18 can infer the presence of an object 11 in the vicinity of the ultrasonic sensor 1.

[0155] iii. If the fraction of the value of the first time difference 101 divided by the value of the second time difference 501 is less than the minimum time ratio threshold, then the computer core 2 and / or the digital processing and filtering stage 18 can infer that the object 11 is very close to the ultrasonic sensor 1.

[0156] iv. If the fraction of the value of the second time difference 501 divided by the value of the first time difference 101 is greater than the maximum time ratio threshold, then the computer core 2 and / or the digital processing and filtering stage 18 can infer that the object 11 is very close to the ultrasonic sensor 1.

[0157] Alternatively, the computer core 2 can also transmit the time values ​​of the first time point 102, the second time point 103, the third time point 502, and the fourth time point 503 to the control unit 21 via the data bus 20. In this case, the control unit 21 preferably performs the above comparisons i to iv in place of the computer core 2.

[0158] Alternatively, the computer core 2 can also transmit the time values ​​of the first time difference 101 and the second time difference 501 to the control unit 21 via the data bus 20. In this case, the control unit 21 preferably performs the above comparisons i to iv in place of the computer core 2.

[0159] If the computer core 2 and / or the digital processing and filtering stage 18 infer that an object 11 is present in the vicinity of the ultrasonic sensor 1, the computer core 2 preferably transmits the result signal to the control unit 21 via the data bus 20.

[0160] It will be apparent to those skilled in the art that, when evaluating using the preceding alternatives i to iv, it is no longer necessary to use a functionally equivalent sub-device of the EXOR circuit 30 or the evaluation circuit 37. In this case, the timer 41 and the functionally equivalent sub-device of the EXOR logic operation 30 or the evaluation circuit 37 can be omitted. In this case, the second comparator output signal 28 replaces the output signal 31 of the EXOR gate 30 as the drive signal for the digital processing and filtering stage 18 or the computer core 2.

[0161] Figure 2 An exemplary time progression of the amplitude curve 107 of the envelope signal of an ultrasonic pulse train is shown. Figure 1 In this case, this is the envelope signal of the amplified electro-ultrasound received signal 15. Figure 4In this case, this is the envelope signal of the processed digital ultrasound received signal 34. The Y-axis represents the amplitude curve 107 of the envelope signal. Here, the amplitude curve 107 is given as an example in the LSB of the analog-to-digital converter 16. Initially, during the transmission phase, the time progression of the amplitude curve 107 shows over-control of the amplitude curve 107 of the envelope signal by the analog-to-digital converter 16 and / or amplifier 14. At a first time point 102, the amplitude of the electro-ultrasound received signal 13 is lower than the first threshold of the first threshold signal 24. At this first time point 102, the first comparator output signal 25 changes its logic state and exhibits a first edge. After a first time difference 101, at a second time point 103, the amplitude curve 107 of the envelope signal is lower than the second threshold 105 of the second threshold signal 27.

[0162] Figure 3 This demonstrates what is understood in the detailed exposition of the technical teachings in this document. Figure 1 The duration of the first time difference 101 is temperature dependent on the temperature of the ultrasonic transducer 9.

[0163] Figure 4 To a large extent correspond to Figure 1 However, envelope filter 33 is now not like... Figure 1 Instead of being part of amplifier 14, it is designed and arranged as digital envelope filter 33 in the signal path following analog-to-digital converter 16. The second comparison logic circuit, functionally equivalent to the second comparator 26, compares the second threshold of the second threshold signal 27 with the value of the processed digital ultrasound received signal 34. Figure 4 In the example, amplifier 14 amplifies and / or filters the electro-ultrasound received signal 13 to obtain an amplified electro-ultrasound received signal 15. Figure 4 In the example, amplifier 14 typically does not include an envelope filter. Figure 1 The examples are different. Figure 4 In the example, the envelope filter 33 is preferably digital. Therefore, in Figure 4 In the example, the envelope filter 33 is exemplarily located in the digital portion 35 of the signal path following the analog-to-digital converter 16. Therefore, in Figure 4 In the example, the amplified electro-ultrasound received signal 15 typically does not include the envelope signal. Figure 4 In the example, analog-to-digital converter 16 converts the amplified electro-ultrasound received signal 15 into a digital ultrasound received signal 17. Figure 4 In the example, envelope filter 33 filters the digitized ultrasound received signal 17 into a processed digital ultrasound received signal 34. Preferably, the processed digital ultrasound received signal 34 includes an envelope signal, or preferably, the processed digital ultrasound received signal 34 is a digitized envelope signal. Therefore, in Figure 4In the example, the analog-to-digital converter 16 is located before the processed digital ultrasound received signal 34 in the signal path. A second comparison logic circuit, functionally equivalent to the second comparator 26, compares the second threshold of the second threshold signal 27 with the value of the processed digital ultrasound received signal 34. Based on the result of this comparison, the already described second comparator output signal 28 is generated. Figure 4 In the diagram, the second comparator logic circuit is drawn using the symbol for the second comparator 26 to illustrate functional equivalence.

[0164] Figure 4 The remaining signal processing corresponds to Figure 1 Signal processing.

[0165] Figure 5 Corresponding to Figure 1 Therefore, timer 41 no longer inverts the second comparator output signal 28. Now, the digital processing and filtering stage 18 and / or the computer core 2 preferably directly evaluate the second comparator output signal 28.

[0166] Figure 6 Corresponding to Figure 4 Therefore, timer 41 no longer inverts the second comparator output signal 28. Now, the digital processing and filtering stage 18 and / or the computer core 2 preferably directly evaluate the second comparator output signal 28.

[0167] Figure 7 An exemplary time progression of the amplitude curve 106 for the envelope signal of the first short ultrasonic pulse train 504 and the subsequent long ultrasonic pulse train 505, exemplarily shown in the LSB of the analog-to-digital converter 16, is illustrated. Figure 1 In this case, this is the envelope signal of the amplified electro-ultrasound received signal 15. Figure 4 In this case, it is the envelope signal of the processed digital ultrasound received signal 34. For the method applied, the envelope signal is analog ( Figure 1 () or numbers () Figure 4 This is irrelevant. The first comparator 23 typically compares the amplitude of the electro-ultrasound received signal 13 with a first threshold value of the first threshold signal 24. If the amplitude of the electro-ultrasound received signal 13 is lower than the first threshold value of the first threshold signal 24, the first comparator 23 transmits the signal at the first time point 102 through a first edge change in its first comparator output signal 25. Figure 7The edge change of the first comparator output signal 25 is plotted in the diagram. The Y-axis scale does not point to the first comparator output signal 25. The reader can assume that the value of the first comparator output signal 25 changes from a first logic value to a second logic value at the first time point 102. If a new ultrasonic pulse is emitted after the last emission of the last ultrasonic pulse, after an emission cycle 506, the value of the first comparator output signal 25 preferably changes back from the second logic value to the first logic value.

[0168] Figure 7 The example shows a first ultrasonic envelope signal 504 preceding a second ultrasonic envelope signal 505, which is part of the amplitude response 106 of the amplitude curve 107 of the envelope signal. Figure 7 In the example, the exemplary compensation measurement 504 in the form of a first ultrasonic envelope signal precedes the exemplary main ultrasonic measurement 505 in the form of a second ultrasonic envelope signal. Preferably, the ultrasonic sensor 1 performs the compensation measurement 504 using an ultrasonic pulse train having only a few, preferably only one, ultrasonic pulses. Preferably, the ultrasonic sensor 1 performs the main ultrasonic measurement 505 using an ultrasonic pulse train having multiple, preferably more than two, ultrasonic pulses.

[0169] When the first time point 102 is reached, the ultrasonic sensor 1 reaches the end of the transmission phase for compensation measurement 504. As the oscillating element 8 of the ultrasonic transducer 9 oscillates further, at the second time point 103, the amplitude curve 106 of the envelope signal falls below the first threshold 105 of the first threshold signal 27. The time difference between the second time point 103 and the first time point 102 represents the first time difference 101. This first time difference 101 is a reference value by which, during the subsequent main ultrasonic measurement 505 of a longer ultrasonic pulse train 10 with multiple ultrasonic pulses, the ultrasonic sensor 1, its computer core 2, or its digital processing and filtering stage 18 evaluates whether the subsequently detected second time difference 501 deviates numerically from the first time difference 101, such that the ultrasonic sensor 1, its computer core 2, or its digital processing and filtering stage 18 must assume that the object 11 is within close proximity of the ultrasonic sensor 1. When the third time point 502 is reached, the ultrasonic sensor 1 reaches the end of the transmission phase for the associated main ultrasonic measurement 505. As the oscillating element 8 of the ultrasonic transducer 9 oscillates further, at the fourth time point 503, the amplitude curve 106 of the envelope signal again falls below the first threshold 105 of the first threshold signal 27. The time difference between the fourth time point 503 and the third time point 502 represents the second time difference 501.

[0170] If there is no object 11 within close proximity to the ultrasonic sensor 1, the oscillating element 8 of the ultrasonic transducer 9 can oscillate without obstruction. This is the first operating condition described below. The detailed explanation of the proposed scheme here shows that, in this case, there is no significant deviation between the first time difference 101 and the second time difference 501. In this first operating condition, the deviation between the first time difference 101 and the second time difference 501 can generally be attributed to insignificant interference.

[0171] However, if object 11 is within close range of ultrasonic sensor 1, the oscillating element 8 of ultrasonic transducer 9 can only oscillate unimpeded under the compensation measurement 504. In this case, the ultrasonic pulse train 10 is still short enough in time that the oscillating element 8 of ultrasonic transducer 9 oscillates before the reflected ultrasonic pulse train 12 reaches the oscillating element 8 again. Therefore, if object 11 is within close range of ultrasonic sensor 1, the oscillating element 8 of ultrasonic transducer 9 can no longer oscillate unimpeded under the main ultrasonic measurement 505. In this case, the duration of ultrasonic pulse train 10 is too long, so that when the reflected ultrasonic pulse train 12 reaches the oscillating element 8 again, the oscillating element 8 of ultrasonic transducer 9 has not yet oscillated. This is the second operating condition described below. A detailed explanation of the scheme proposed herein shows that, in this case, the first time difference 101 is significantly different from the second time difference 501. In this second operating condition, the value of the first time difference 101 is smaller than the second time difference 501, i.e., the time is shorter. Now, the ultrasonic sensor 1, or its computer core 2, or its digital processing and filtering stage 18, evaluates these different time lengths of the first time difference 101 and the second time difference 501. For this purpose, the ultrasonic sensor 1, or its computer core 2, or its digital processing and filtering stage 18, performs compensation measurements 504 from time to time, otherwise working in conjunction with the main ultrasonic measurement 505 is sufficient.

[0172] For example, the ultrasonic sensor 1, its computer core 2, or its digital processing and filtering stage 18 can be performed in the following ways:

[0173] i. The ultrasonic sensor 1, its computer core 2, or its digital processing and filtering stage 18 forms a difference between the value of the second time difference 501 and the value of the first time difference 101. If the value is greater than zero plus an optional first lead, the ultrasonic sensor 1, its computer core 2, or its digital processing and filtering stage 18 preferably infers the presence of an object 11 in the vicinity of the ultrasonic sensor 1.

[0174] ii. The ultrasonic sensor 1, its computer core 2, or its digital processing and filtering stage 18 forms a difference between the value of the first time difference 101 and the value of the second time difference 501. If the value is less than zero minus an optional second lead, the ultrasonic sensor 1, its computer core 2, or its digital processing and filtering stage 18 preferably infers the presence of an object 11 in the vicinity of the ultrasonic sensor 1.

[0175] iii. The ultrasonic sensor 1, its computer core 2, or its digital processing and filtering stage 18 divides the value of the second time difference 501 by the value of the first time difference 101. If the value is greater than 1 (a) plus an optional third lead, the ultrasonic sensor 1, its computer core 2, or its digital processing and filtering stage 18 preferably infers the presence of an object 11 in the vicinity of the ultrasonic sensor 1.

[0176] iv. The ultrasonic sensor 1, its computer core 2, or its digital processing and filtering stage 18 divides the value of the first time difference 101 by the value of the second time difference 501. If the value is less than 1 (a) minus an optional fourth lead, the ultrasonic sensor 1, its computer core 2, or its digital processing and filtering stage 18 preferably infers the presence of an object 11 in the vicinity of the ultrasonic sensor 1.

[0177] The first to fourth lead values ​​are preferably positive. It is possible to set the first to fourth lead values ​​to zero. The proposed solution here suggests choosing a larger lead value.

[0178] Figure 7 The Y-axis shows an exemplary scale of the amplitude curve 106 of the envelope signal, exemplarily represented here in LSB form of the analog-to-digital converter 16. Figure 1 In this case, this is the envelope signal of the amplified electro-ultrasound received signal 15. Figure 4 In this case, it is the envelope signal of the processed digital ultrasound received signal 34.

[0179] The time axis (X-axis) shows the number of past sampling points (counts) of the analog-to-digital converter 16.

[0180] Figure 8 This illustrates what is understood in the technical teachings presented in this article. Figure 1 and Figures 4 to 6 The temperature dependence of the first time difference 101 on temperature, and the understanding gained in the technical teachings of this paper. Figure 1 and Figures 4 to 6The second time difference 501 is temperature-dependent. Here, there is a first operating condition in which no object 11 is located within close range of the ultrasonic sensor 1. It can be easily seen that for the same temperature, the first time difference 101 and the second time difference 501 are not significantly different. Therefore, the essence of this scheme is to perform a compensation measurement 504 only from time to time using a short ultrasonic pulse train 10 with several ultrasonic pulses, preferably only one ultrasonic pulse, and then detect the first time difference 101. Subsequently, a main ultrasonic measurement 505 is performed using a longer ultrasonic pulse train 505 with several ultrasonic pulses, and the second time difference 501 is detected. If the value of the first time difference 501 is significantly shorter in time than the value of the second time difference 101, it is inferred that an object 11 is present within close range of the ultrasonic sensor 1.

[0181] Figure 9 The first exemplary order of the exemplary measurement order is shown.

[0182] In the first step 900, the ultrasonic sensor 1 performs a compensation measurement 504 using a short transmitted ultrasonic pulse train 10 having several ultrasonic pulses, preferably only one ultrasonic pulse. In the first step 900, the ultrasonic sensor determines the value of the duration of the first time difference 101. Preferably, the computer core 2 and / or the digital processing and filtering stage 18 store the value of the duration of the first time difference 101 in the memory of the ultrasonic sensor 1. Typically, the computer core 2 controls this first step 900 in cooperation with other device parts of the ultrasonic sensor 1. Instead of the computer core 2, the control unit 21 of the ultrasonic sensor system 22 can theoretically also control this first step 900 and / or partially take over the functions of the ultrasonic sensor 1 in this first step 900.

[0183] In the second step 901, the ultrasonic sensor 1 performs a primary ultrasonic measurement 505 using a long emitted ultrasonic pulse train 10 with multiple ultrasonic pulses. In the second step 901, the ultrasonic sensor determines the value of the duration of the second time difference 501. Typically, the computer core 2 controls this second step 901 in cooperation with other components of the ultrasonic sensor 1. Alternatively, the control unit 21 of the ultrasonic sensor system 22 can theoretically also control this second step 901 and / or partially take over the functions of the ultrasonic sensor 1 in this second step 901.

[0184] In the third step 902, the ultrasonic sensor 1 compares the value of the duration of the second time difference 501 with the value of the duration of the first time difference 101. As described above, this can be accomplished, for example, by forming a difference or a ratio. Typically, the computer core 2 controls this third step 902 in cooperation with other device parts of the ultrasonic sensor 1. Instead of the computer core 2, the control unit 21 of the ultrasonic sensor system 22 can theoretically also control this third step 902 and / or partially take over the functions of the ultrasonic sensor 1 in this third step 902.

[0185] Based on the comparison results, the fourth step 903 can then be performed. If the length of the second time difference 501 is greater than the length of the first time difference 101, then the ultrasonic sensor 1 determines in the fourth step 903 that an object 11 is present in its vicinity. Preferably, in this fourth step 903, the computer core 2 sends a signal to the control unit 21 of the ultrasonic sensor system 22 to notify that an object 11 is present in the vicinity of the ultrasonic sensor 1. Typically, the computer core 2 controls this fourth step 903 in cooperation with other device parts of the ultrasonic sensor 1. Instead of the computer core 2, the control unit 21 of the ultrasonic sensor system 22 can theoretically also control this fourth step 903 and / or partially take over the functions of the ultrasonic sensor 1 in this fourth step 903.

[0186] Based on the comparison results, a fifth step 904 may follow the third step 902. If the length of the second time difference 501 is less than the length of the first time difference 101, the ultrasonic sensor 1 determines in the fifth step 904 that there is no object 11 in its vicinity. Then, preferably, the ultrasonic sensor 1 checks in this fifth step 904 whether the number of main ultrasonic measurements 505 has exceeded or reached the maximum number since the last compensation measurement 504. If this is the case, the ultrasonic sensor 1 preferably performs another compensation measurement 504 in the first step 900, typically restarting the cycle. If this is not the case, the ultrasonic sensor 1 preferably performs the next main ultrasonic measurement 505. The ultrasonic sensor 1 typically waits until the transmission of the immediately preceding ultrasonic pulse train 10 begins and the transmission cycle 506 ends before performing the next compensation measurement 504 or the next main ultrasonic measurement 505. Typically, the computer core 2 controls this fifth step 904 in cooperation with other device parts of the ultrasonic sensor 1. Instead of the computer core 2, the control unit 21 of the ultrasonic sensor system 22 can theoretically also control the fifth step 904 and / or partially take over the function of the ultrasonic sensor 1 in the fifth step 904.

[0187] Figure 10 A second exemplary order of measurement is shown.

[0188] In the first step 1000, the ultrasonic sensor 1 performs a compensation measurement 504 using a short transmitted ultrasonic pulse train 10 having several ultrasonic pulses, preferably only one ultrasonic pulse. In the first step 1000, the ultrasonic sensor 1 determines the value of the duration of the first time difference 101. Preferably, the computer core 2 and / or the digital processing and filtering stage 18 store the value of the duration of the first time difference 101 in the memory of the ultrasonic sensor 1. Typically, the computer core 2 controls this first step 1000 in cooperation with other device parts of the ultrasonic sensor 1. Instead of the computer core 2, the control unit 21 of the ultrasonic sensor system 22 can theoretically also control this first step 1000 and / or partially take over the functions of the ultrasonic sensor 1 in this first step 1000.

[0189] In the second step 1001, the ultrasonic sensor 1 performs the primary ultrasonic measurement 505 using a long emitted ultrasonic pulse train 10 with multiple ultrasonic pulses. However, in the second step 1001, the ultrasonic sensor is now not like... Figure 9 The second time difference 501 is determined as described above. Alternatively, the ultrasonic sensor 1 determines a third time point 502 and starts timer 41. Typically, the computer core 2 controls this second step 1001 in cooperation with other parts of the ultrasonic sensor 1. Instead of the computer core 2, the control unit 21 of the ultrasonic sensor system 22 can theoretically also control this second step 1001 and / or partially take over the functions of the ultrasonic sensor 1 in this second step 1001.

[0190] Preferably, in the third step 1002, the ultrasonic sensor 1 changes the value of its timer 41 by the timer increment. Preferably, the ultrasonic sensor 1 increments the value of its timer 41 in this third step 1002. Typically, the computer core 2 controls this third step 1002 in cooperation with other components of the ultrasonic sensor 1. Instead of the computer core 2, the control unit 21 of the ultrasonic sensor system 22 can theoretically also control this third step 1002 and / or partially take over the functions of the ultrasonic sensor 1 in this third step 1002.

[0191] In the fourth step 1003, the ultrasonic sensor 1 compares the value of timer 41 with the value of the first time difference 101. If the value of timer 41 is less than the first time difference 101 plus a preferred lead, the oscillating element 8 of the ultrasonic transducer 9 of the ultrasonic sensor 1 may not yet be oscillating. In this case, the process performed by the ultrasonic sensor 1 jumps back to the third step 1002. If the value of timer 41 is greater than the first time difference 101 plus a preferred lead, the oscillating element 8 of the ultrasonic transducer 9 of the ultrasonic sensor 1 should be oscillating when there is no object 11 in the vicinity of the ultrasonic sensor 1. In this case, the process performed by the ultrasonic sensor 1 further jumps to the fifth step 1004. Typically, the computer core 2 controls this fourth step 1003 in cooperation with other device parts of the ultrasonic sensor 1. Instead of the computer core 2, the control unit 21 of the ultrasonic sensor system 22 can theoretically also control this fourth step 1003 and / or partially take over the functions of the ultrasonic sensor 1 in this fourth step 1003.

[0192] In the fifth step 1004, the ultrasonic sensor compares the amplitude 107 of the envelope signal with a second threshold 105. If the amplitude 107 of the envelope signal is numerically less than the second threshold 105, the ultrasonic sensor 1 infers that there is no object 11 in the vicinity of the ultrasonic sensor 1. In this case, the ultrasonic sensor 1 continues to execute the method through the seventh step 1006. If the amplitude 107 of the envelope signal is numerically greater than the second threshold 105, the ultrasonic sensor 1 infers that there is an object 11 in the vicinity of the ultrasonic sensor 1. In this case, the ultrasonic sensor 1 continues to execute the method through the sixth step 1005. Typically, the computer core 2 controls this fifth step 1004 in cooperation with other device parts of the ultrasonic sensor 1. Instead of the computer core 2, the control unit 21 of the ultrasonic sensor system 22 can theoretically also control this fifth step 1004 and / or partially take over the functions of the ultrasonic sensor 1 in this fifth step 1004.

[0193] In the sixth step 1005, preferably, the computer core 2 controls the sixth step 1005 in cooperation with other device components of the ultrasonic sensor 1. Preferably, the computer core 2 signals the control unit 21 of the ultrasonic sensor system 22 to notify that the object 11 is present in the vicinity of the ultrasonic sensor 1. Typically, the computer core 2 controls the sixth step 1005 in cooperation with other device components of the ultrasonic sensor 1. Instead of the computer core 2, the control unit 21 of the ultrasonic sensor system 22 can theoretically also control the sixth step 1005 and / or partially take over the functions of the ultrasonic sensor 1 in the sixth step 1005.

[0194] In the seventh step 1006, the ultrasonic sensor 1 preferably checks whether the number of primary ultrasonic measurements 505 has exceeded or reached the maximum number since the last compensation measurement 504. If this is the case, the ultrasonic sensor 1 preferably performs another compensation measurement 504 in the first step 1000, typically restarting the cycle. If this is not the case, the ultrasonic sensor 1 preferably performs the next primary ultrasonic measurement 505 in the second step 1001. The ultrasonic sensor 1 typically waits until the transmission cycle 506 ends from the start of the transmission of the immediately preceding ultrasonic pulse train 10 before performing the next compensation measurement 504 or the next primary ultrasonic measurement 505. Typically, the computer core 2 controls this seventh step 1006 in cooperation with other device parts of the ultrasonic sensor 1. Instead of the computer core 2, the control unit 21 of the ultrasonic sensor system 22 can theoretically also control this seventh step 1006 and / or partially take over the functions of the ultrasonic sensor 1 in this seventh step 1006.

[0195] Figure 11 Corresponding to Figure 5 The difference is Figure 11 There is no timer 41. Therefore, it can only execute according to... Figure 9 The process.

[0196] Figure 12 Corresponding to Figure 3 The difference is Figure 12 There is no timer 41. Therefore, it can only execute according to... Figure 9 The process.

[0197] Figure 13 Corresponding to Figure 9 The difference lies in that, after determining in step 903 that object 11 exists within the vicinity of ultrasonic sensor 1, ultrasonic sensor 1 now switches to ultrasonic master measurement 505 with short ultrasonic pulses 10 until object 11 disappears from the vicinity of ultrasonic sensor 1. In extreme cases, ultrasonic sensor 1 therefore performs only compensation measurement 504, preferably using each emitted ultrasonic pulse train 10 with only one ultrasonic pulse, until object 11 disappears from the vicinity of ultrasonic sensor 1. Thus, ultrasonic sensor 1 infers the presence of object 11 within its vicinity, and then, if such object 11 is within the vicinity of ultrasonic sensor 1, shortens the duration of the emitted ultrasonic pulse train 10. Therefore, ultrasonic sensor 1 is able to detect the distance of object 11 within its vicinity. In the case where object 11 is within the vicinity of ultrasonic sensor 1, if the emitted ultrasonic pulse train 10 is not shortened, since the reflected ultrasonic pulse train 12 will arrive before the oscillating element 8 of ultrasonic sensor 1 has oscillated, ultrasonic sensor 1 will be unable to detect the distance between ultrasonic sensor 1 and object 11 if the duration of the emitted ultrasonic pulse train 10 is not shortened.

[0198] In the sixth step 905, the ultrasonic sensor 1 emits a shortened ultrasonic pulse train 10 with a second duration, preferably shorter than the first duration of the ultrasonic pulse train 10 emitted by the ultrasonic sensor 1 in the second step 901. Preferably, the second duration of the ultrasonic pulse train 10 emitted in this sixth step 905 is equal to the duration of the short emitted ultrasonic pulse train 10 emitted by the ultrasonic sensor 1 in the first step 900 for compensation measurement 504. Typically, then, in a preferred embodiment, the ultrasonic pulse train 10 emitted in the sixth step 905 corresponds to the ultrasonic pulse train 10 used by the ultrasonic sensor 1 in the first step 900 for compensation measurement 504. In this sixth step 905, the ultrasonic sensor 1 detects the distance to the object 11 within its proximity.

[0199] In the seventh step 906, the ultrasonic sensor 1 checks whether the object 11 is still within its proximity. To do this, the ultrasonic sensor 1 compares the distance from the object 11 detected by a short transmitted ultrasonic pulse train 10 to a distance threshold. If the detected distance is less than the distance threshold, the object 11 is still within the proximity of the ultrasonic sensor 1, and the ultrasonic sensor 1 proceeds to the sixth step 905. If the detected distance is greater than the distance threshold, the object 11 is no longer within the proximity of the ultrasonic sensor 1, and the ultrasonic sensor 1 continues to execute the first step 900. Assuming that the first step 900 corresponds to the sixth step 905 and the ultrasonic sensor 1 determines the first time difference 101 in the sixth step 905, the ultrasonic sensor 1 can also directly continue to execute the second step 901.

[0200] Figure 14 Corresponding to Figure 10The difference lies in that, after determining in step 1005 that object 11 exists within the vicinity of ultrasonic sensor 1, ultrasonic sensor 1 now switches to primary ultrasonic measurement 505 with short emitted ultrasonic pulses 10 until object 11 disappears from the vicinity of ultrasonic sensor 1. In extreme cases, ultrasonic sensor 1 therefore performs only compensation measurement 504, preferably using a train of ultrasonic pulses 10 with only one emitted ultrasonic pulse per emitted pulse, until object 11 disappears from the vicinity of ultrasonic sensor 1. Thus, ultrasonic sensor 1 infers the presence of object 11 within its vicinity, and then, if such an object 11 is within the vicinity of ultrasonic sensor 1, shortens the duration of the emitted ultrasonic pulse train 10. Thus, ultrasonic sensor 1 positions itself to detect the distance of object 11 within its vicinity. If the emitted ultrasonic pulse train 10 is not shortened when the object 11 is within close range of the ultrasonic sensor 1, the reflected ultrasonic pulse train 12 will arrive before the oscillating element 8 of the ultrasonic sensor 1 has oscillated. Therefore, the ultrasonic sensor 1 will not be able to detect the distance between the ultrasonic sensor 1 and the object 11 if the time of the emitted ultrasonic pulse train 10 is not shortened.

[0201] In the eighth step 1007, the ultrasonic sensor 1 emits a shortened ultrasonic pulse train 10 with a second duration, preferably shorter than the first duration of the ultrasonic pulse train 10 emitted by the ultrasonic sensor 1 in the second step 1001. Preferably, the second duration of the ultrasonic pulse train 10 emitted in this eighth step 1007 is equal to the duration of the short emitted ultrasonic pulse train 10 emitted by the ultrasonic sensor 1 in the first step 1000 for compensation measurement 504. Then, typically, in a preferred embodiment, the ultrasonic pulse train 10 emitted in the eighth step 1007 corresponds to the ultrasonic pulse train 10 used by the ultrasonic sensor 1 for compensation measurement 504 in the first step 1000. In this sixth step 905, the ultrasonic sensor 1 detects the distance to the object 11 within its proximity.

[0202] In the ninth step 1008, the ultrasonic sensor 1 checks whether the object 11 is still within its proximity. To do this, the ultrasonic sensor 1 compares the distance from the object 11 to the ultrasonic sensor 1 detected in the eighth step 1007 using a short ultrasonic pulse train 10 with a distance threshold. If the detected distance is less than the distance threshold, the object 11 is still within the proximity of the ultrasonic sensor 1, and the ultrasonic sensor 1 continues with the eighth step 1007. If the detected distance is greater than the distance threshold, the object 11 is no longer within the proximity of the ultrasonic sensor 1, and the ultrasonic sensor 1 continues with the first step 1000. If the first step 1000 corresponds to the eighth step 1007 and the ultrasonic sensor 1 determines a first time difference 101 in the eighth step 1007, the ultrasonic sensor 1 can also directly continue with the second step 1001.

[0203] but Figure 13 and Figure 14 The process can be summarized as follows:

[0204] i. If there is no object 11 in the vicinity of the ultrasonic sensor 1, an ultrasonic main measurement 505 is performed using an ultrasonic pulse train 10 with a first time length. If there is an object 11 in the vicinity of the ultrasonic sensor 1, the presence of the object 11 in the vicinity of the ultrasonic sensor 1 is detected.

[0205] ii. The first time length of the emitted ultrasonic pulse train 10 is shortened to the second time length of the emitted ultrasonic pulse train 10, and the distance between the ultrasonic sensor 1 and the object 11 is detected during the duration during which the object 11 is within close range of the ultrasonic sensor 1.

[0206] other

[0207] The foregoing description is not exhaustive and does not limit the disclosure to the examples shown. Those skilled in the art will be able to understand and make other modifications to the disclosed examples by referring to the accompanying drawings, the disclosure, and the claims. The indefinite article "a" and its variations do not exclude a plural, and reference to a specific number of elements does not preclude the possibility of more or fewer elements. A single entity may perform the function of multiple elements mentioned in the disclosure, and conversely, multiple elements may perform the function of one entity. Many substitutions, equivalents, variations, and combinations are possible without departing from the scope of this disclosure.

[0208] Unless otherwise stated, all features of the invention can be freely combined. This applies to the entire document presented herein. Furthermore, unless otherwise stated, features described in the description of the drawings can also be freely combined with other features of the invention. Therefore, it is explicitly stated that the individual features of the embodiments are not limited to combinations with other features of the embodiments. Moreover, objective features of the apparatus can also be used as method features in a restatement, and method features can be used as objective features of the apparatus in a restatement. Therefore, such restatements are automatically disclosed.

[0209] In the foregoing detailed description, reference has been made to the accompanying drawings. The examples in the specification and drawings should be considered illustrative and not as limitations on the specific examples or elements described. Multiple examples can be derived from the foregoing specification and / or drawings and / or claims by modifying, combining, or changing certain elements. Furthermore, those skilled in the art can derive examples or elements not described literally from the specification and / or drawings.

[0210] List of reference numerals

[0211] 1. Ultrasonic sensor

[0212] 2. Computer core of ultrasonic sensor 1

[0213] 3. Digital ultrasonic pulse train generator for ultrasonic sensor 1

[0214] 4. Control signals for the digital ultrasonic pulse train generator 3 of ultrasonic sensor 1

[0215] 5. Digital Ultrasonic Transmission Signal

[0216] 6. Analog ultrasonic transmission stage of ultrasonic sensor 1

[0217] 7. Control signal of ultrasonic sensor 1

[0218] 8. Oscillating element of ultrasonic transducer 9

[0219] 9. Ultrasonic transducer

[0220] 10 emitted ultrasonic pulse trains

[0221] 11. Objects near the vehicle

[0222] 12 Reflected ultrasonic pulse trains

[0223] 13 Electro-ultrasound receiving signal

[0224] 14 Amplifier

[0225] 15 Amplified electro-ultrasound receiving signal

[0226] 16. Analog-to-digital converter for ultrasonic sensor 1

[0227] 17 Digital ultrasound receiving signal

[0228] 18 Digital processing and filtering stages

[0229] 19. Filtered ultrasonic received signal

[0230] 20 Data Bus

[0231] 21 Control unit of ultrasonic sensor system 22

[0232] 22 Ultrasonic Sensor System

[0233] 23 First Comparator

[0234] 24 First threshold signal

[0235] 25 First comparator output signal

[0236] 26. The second comparator. Figure 4 In this circuit, a second comparison logic circuit replaces the second comparator. The second comparison logic circuit is the digital functional equivalent of the second comparator. The second comparator compares the second threshold signal 27 with the value of the amplified electro-ultrasound received signal 15. At this point, the analog-to-digital converter 16 is located after the amplified electro-ultrasound received signal 15 in the signal path. (See also...) Figure 1 The functionally equivalent second comparison logic circuit compares the second threshold of the second threshold signal 27 with the value of the processed digital ultrasound received signal 34, which is an envelope signal or preferably includes an envelope signal. In this case, the analog-to-digital converter 16 is arranged in the signal path before the processed digital ultrasound received signal 34.

[0237] (See also) Figure 4 )

[0238] 27 Second threshold signal

[0239] 28 Second comparator output signal

[0240] 29 Threshold generating device

[0241] 30 EXOR circuit

[0242] 31. Output signal of EXOR gate 30

[0243] 32 EXOR control signals

[0244] 33 Envelope Filter

[0245] 34. The processed digital ultrasound received signal, preferably an envelope signal or including an envelope signal.

[0246] 35. Numerical Part

[0247] 36. Simulation Section

[0248] 37 Evaluation Circuit

[0249] 38 Positive power supply voltage line

[0250] 39 Voltage Regulator

[0251] 40 Negative power supply voltage line

[0252] 41 Timer

[0253] 101 The first time difference between the first time point 102 of the first edge change of the first comparator output signal 25 and the second time point 103 of the subsequent second edge change of the second comparator output signal 28

[0254] 102 The first time point of the first edge change of the first comparator output signal 25

[0255] 103 The second time point of the second edge change of the second comparator output signal 28

[0256] 105 Second threshold signal 27 second threshold

[0257] The amplitude curve of the 106-element envelope signal is exemplarily represented here by the LSB of analog-to-digital converter 16. Figure 1 In this case, this is the envelope signal of the amplified electro-ultrasound received signal 15. Figure 4 In this case, it is the envelope signal of the processed digital ultrasound received signal 34.

[0258] 107. Amplitude curve of the envelope signal. Figure 1 In this case, this is the envelope signal of the amplified electro-ultrasound received signal 15. Figure 4 In this case, it is the envelope signal of the processed digital ultrasound received signal 34.

[0259] 108 Overload caused by the amplitude of the envelope signal 107

[0260] 501 The second time difference between the third time point 502 of the third edge change of the first comparator output signal 25 and the fourth time point 503 of the subsequent fourth edge change of the second comparator output signal 28

[0261] 502 The third time point of the third edge change of the first comparator output signal 25

[0262] 503 The fourth time point of the fourth edge change of the second comparator output signal 28

[0263] 504 First ultrasonic envelope signal (exemplary compensated measurement)

[0264] 505 Second ultrasonic envelope signal (exemplary main ultrasonic measurement)

[0265] 506 transmission cycle

[0266] Number of sampling points for 507 analog-to-digital converter 16

[0267] 900 First Step

[0268] 901 Second Step

[0269] 902 Third Step

[0270] 903 Fourth Step

[0271] 904 Step 5

[0272] 905 Step Six

[0273] 906 Seventh Step

[0274] 1000 First Step

[0275] 1001 Second Step

[0276] 1002 Third Step

[0277] 1003 Fourth Step

[0278] 1004 Fifth Step

[0279] 1005 Step Six

[0280] 1006 Seventh Step

[0281] Step 8 of 1007

[0282] Step 9 of 1008

[0283] SdT Existing Technology

[0284] T is temperature, in °C.

[0285] t time

Claims

1. An evaluation method for the electro-ultrasonic received signal (13) of the piezoelectric oscillation element (8) of the ultrasonic transducer (9) of an ultrasonic sensor (1) for improving near-field detection, The method includes the following steps: - At least one short ultrasonic pulse train (504) is transmitted during the first transmission cycle; - In the first transmission cycle, the value of the electro-ultrasound received signal (13) is compared with a first threshold; - Detect a first time point (102) within the first transmission cycle of the short ultrasonic pulse train (504), at which time point (102) the value of the electro-ultrasonic received signal (13) is lower than the first threshold; and - During the first transmission cycle, the electro-ultrasound receiving signal (13) is amplified into an amplified ultrasound receiving signal (15); - In the first transmission cycle, the value of the amplified ultrasonic received signal (15) is compared with a second threshold (105); - Detect a second time point (103) within the first transmission cycle of the short ultrasonic pulse train (504), at which time point (103), the amplitude (107) of the amplified ultrasonic received signal (15) is lower than the second threshold (105); and - Determine the first time difference (101) between the first time point (102) and the second time point (103); - At least one long ultrasonic pulse train (505) is emitted during the second transmission cycle; - wherein the second transmission cycle follows the first transmission cycle in time; - In the second transmission cycle, the value of the electro-ultrasound received signal (13) is compared with the first threshold; - Detect a third time point (502) within the second transmission period of the long ultrasonic pulse train (505), at which the value of the electro-ultrasound received signal (13) is lower than the first threshold; and - During the second transmission cycle, the electro-ultrasound receiving signal (13) is amplified into an amplified ultrasound receiving signal (15); - In the second transmission cycle, the value of the amplified ultrasonic received signal (15) is compared with the second threshold (105), and as a result of the comparison, a second comparator output signal (28) is formed; -At the third time point (502), start timer (41); and -If so, at the time point when the timer (41) detects that a time period corresponding to the first time difference (101) plus the lead time has elapsed since its start, the value of the amplitude (107) of the amplified ultrasonic received signal (15) is detected. - The amplitude (107) of the amplified ultrasound received signal (15) thus detected is compared with the second threshold (105); and - When the detected value of the amplitude (107) of the amplified ultrasonic received signal (15) is higher than the second threshold (105), it is inferred that there is an object (11) in the vicinity of the ultrasonic sensor (1).

2. An evaluation method for the electro-ultrasonic receiving signal (13) of the piezoelectric oscillation element (8) of the ultrasonic transducer (9) of an ultrasonic sensor (1) for improving near-field detection, The method includes the following steps: - At least one short ultrasonic pulse train (504) is transmitted during the first transmission cycle; - In the first transmission cycle, the value of the electro-ultrasound received signal (13) is compared with a first threshold; - Detect a first time point (102) within the first transmission cycle of the short ultrasonic pulse train (504), at which time point (102) the value of the electro-ultrasonic received signal (13) is lower than the first threshold; and - During the first transmission cycle, the electro-ultrasound receiving signal (13) is amplified into an amplified ultrasound receiving signal (15); - In the first transmission cycle, the value of the amplified ultrasonic received signal (15) is compared with a second threshold (105); - Detect a second time point (103) within the first transmission cycle of the short ultrasonic pulse train (504), at which time point (103), the amplitude (107) of the amplified ultrasonic received signal (15) is lower than the second threshold (105); and - At least one long ultrasonic pulse train (505) is emitted during the second transmission cycle; - wherein the second transmission cycle follows the first transmission cycle in time; - In the second transmission cycle, the value of the electro-ultrasound received signal (13) is compared with the first threshold; - Detect a third time point (502) within the second transmission period of the long ultrasonic pulse train (505), at which the value of the electro-ultrasound received signal (13) is lower than the first threshold; and - During the second transmission cycle, the electro-ultrasound receiving signal (13) is amplified into an amplified ultrasound receiving signal (15); - In the second transmission cycle, the value of the amplified ultrasonic received signal (15) is compared with the second threshold (105); - Detect a fourth time point (503) within the second transmission cycle of the long ultrasonic pulse train (505), at which time point (503) the amplitude (107) of the amplified ultrasonic received signal (15) is lower than the second threshold (105). - Based on the first time point (102), the second time point (103), the third time point (502) and the fourth time point (503), it is inferred that there is an object (11) in the vicinity of the ultrasonic sensor (1).

3. The method according to claim 2, comprising the following steps: - Determine the first time difference (101) between the first time point (102) and the second time point (103); -Based on the first time difference (101), the third time point (502), and the value of the amplitude (107) of the amplified ultrasonic received signal (15) at a time point later than the value of the first time difference (101) in time than the third time point (502), it is inferred that there is an object (11) in the vicinity of the ultrasonic sensor (1).

4. The method according to claim 3, comprising the following steps: - At a time point later than the third time point (502) by the value of the first time difference (101), when the value of the amplitude (107) of the amplified ultrasonic received signal (15) is greater than the second threshold (105), it is inferred that an object (11) exists in the vicinity of the ultrasonic sensor (1).

5. The method according to claim 2, comprising the following steps: - Determine the first time difference (101) between the first time point (102) and the second time point (103); - Based on the first time difference (101), the third time point (502) and the fourth time point (503), it is inferred that there is an object (11) in the vicinity of the ultrasonic sensor (1).

6. The method according to claim 5, further comprising the following steps: - Determine the second time difference (501) between the third time point (502) and the fourth time point (503); - Based on the first time difference (101) and the second time difference (501), it is inferred that an object (11) exists in the vicinity of the ultrasonic sensor (1).

7. The method according to claim 6, further comprising the following steps: - If the duration of the first time difference (101) is less than the duration of the second time difference (501) plus an optional positive delay value, it is inferred that an object (11) exists in the vicinity of the ultrasonic sensor (1).

8. An evaluation method for the electro-ultrasonic receiving signal (13) of the piezoelectric oscillation element (8) of the ultrasonic transducer (9) of an ultrasonic sensor (1) for improving near-field detection, The method includes the following steps: - At least one short ultrasonic pulse train (504) is transmitted during the first transmission cycle; - In the first transmission cycle, the value of the electro-ultrasound received signal (13) is compared with a first threshold; - Detect a first time point (102) within the first transmission cycle of the short ultrasonic pulse train (504), at which time point (102) the value of the electro-ultrasonic received signal (13) is lower than the first threshold; - During the first transmission cycle, the electro-ultrasound receiving signal (13) is amplified into an amplified ultrasound receiving signal (15); - In the first transmission cycle, the value of the amplified ultrasonic received signal (15) is compared with a second threshold (105); - Detect a second time point (103) within the first transmission cycle of the short ultrasonic pulse train (504), at which time point (103) the amplitude (107) of the amplified ultrasonic received signal (15) is lower than the second threshold (105); - At least one long ultrasonic pulse train (505) is emitted during the second transmission cycle; - wherein the second transmission cycle follows the first transmission cycle in time; - In the second transmission cycle, the value of the electro-ultrasound received signal (13) is compared with a first threshold; - Detect a third time point (502) within the second transmission period of the long ultrasonic pulse train (505), at which the value of the electro-ultrasound received signal (13) is lower than the first threshold; and - During the second transmission cycle, the electro-ultrasound receiving signal (13) is amplified into an amplified ultrasound receiving signal (15); - In the second transmission cycle, the value of the amplified ultrasonic received signal (15) is compared with the second threshold (105); -Based on the comparison results of the first time point (102), the second time point (103), the third time point (502), and the value of the amplified ultrasonic received signal (15) in the second transmission cycle with the second threshold (105), it is inferred that there is an object (11) in the vicinity of the ultrasonic sensor (1).

9. The method of claim 8, further comprising the following steps: - Determine the first time difference (101) between the first time point (102) and the second time point (103); -Based on the first time difference (101), the third time point (502), and the value of the amplitude (107) of the amplified ultrasonic received signal (15) at a time point later than the value of the first time difference (101) in time than the third time point (502), it is inferred that there is an object (11) in the vicinity of the ultrasonic sensor (1).

10. The method of claim 9, further comprising the following steps: - At a time point later than the third time point (502) by the value of the first time difference (101), when the value of the amplitude (107) of the amplified ultrasonic received signal (15) is greater than the second threshold (105), it is inferred that an object (11) exists in the vicinity of the ultrasonic sensor (1).

11. A method of operating an ultrasonic measurement system (22) for an environmental sensing device, in, The ultrasonic measurement system (22) includes an ultrasonic sensor (1), and The ultrasonic sensor (1) has a short range, within which the ultrasonic sensor (1) is no longer able to detect the distance from the ultrasonic sensor (1) to the object (11) using the emitted ultrasonic pulse train (10) of the first time length. The method includes the following steps: - If there is no object (11) near the ultrasonic sensor (1), the main ultrasonic measurement is performed using an ultrasonic pulse train (10) of the first time length, and if there is an object (11) near the ultrasonic sensor (1), the presence of the object (11) is detected near the ultrasonic sensor (1). - The first duration of the emitted ultrasonic pulse train (10) is shortened to the second duration of the emitted ultrasonic pulse train (10), and the distance between the ultrasonic sensor (1) and the object (11) is detected during the duration during which the object (11) is within the close range of the ultrasonic sensor (1). The ultrasonic measurement system (22) is configured to perform an evaluation method for the electro-ultrasonic received signal (13) of the piezoelectric oscillating element (8) of the ultrasonic transducer (9) of the ultrasonic sensor (1) for improving near-field detection as described in any one of claims 1 to 10.

12. An ultrasonic measurement system (22) for an environmental sensing device, in, The ultrasonic measurement system (22) includes an ultrasonic sensor (1), and The ultrasonic sensor (1) has a short range, within which the ultrasonic sensor (1) is no longer able to detect the distance from the ultrasonic sensor (1) to the object (11) using the emitted ultrasonic pulse train (10) of the first time length. If no object (11) is present in the vicinity of the ultrasonic sensor (1), the ultrasonic sensor (1) will at least temporarily emit an ultrasonic pulse train (10) of a first time length to perform the main ultrasonic measurement. Wherein, if an object (11) exists in the vicinity of the ultrasonic sensor (1), the ultrasonic sensor (1) detects the presence of the object (11) in its vicinity, and During the duration in which the object (11) is within close range of the ultrasonic sensor (1), the ultrasonic sensor (1) shortens the first duration of the emitted ultrasonic pulse train (10) to a second duration of the emitted ultrasonic pulse train (10), and During the duration during which the object (11) is within close range of the ultrasonic sensor (1), the ultrasonic sensor (1) detects the distance between the ultrasonic sensor (1) and the object (11), and Wherein, after the object (11) has stopped within close range of the ultrasonic sensor (1), the ultrasonic sensor (1) extends the second time length of the emitted ultrasonic pulse train (10) to the third time length of the emitted ultrasonic pulse train (10), and Wherein, the third time length of the emitted ultrasonic pulse train (10) can be equal to the second time length of the emitted ultrasonic pulse train (10). The ultrasonic measurement system (22) is configured to perform an evaluation method for the electro-ultrasonic received signal (13) of the piezoelectric oscillating element (8) of the ultrasonic transducer (9) of the ultrasonic sensor (1) for improving near-field detection as described in any one of claims 1 to 10.

13. An ultrasonic measurement system (22) for improving environmental sensing devices for close-range detection, in, The ultrasonic measurement system (22) includes an ultrasonic sensor (1), The ultrasonic measurement system (22) performs an evaluation method for the electro-ultrasonic received signal (13) of the piezoelectric oscillation element (8) of the ultrasonic transducer (9) of the ultrasonic sensor (1), and The ultrasonic sensor (1) transmits one or more short ultrasonic pulse trains (504) during the first transmission cycle; The ultrasonic measurement system (22) compares the value of the electro-ultrasonic received signal (13) with a first threshold during the first transmission cycle. The ultrasonic measurement system (22) detects a first time point (102) within the first transmission cycle of the short ultrasonic pulse train (504), at which time point (102), the value of the electro-ultrasonic received signal (13) is lower than the first threshold, and In the first transmission cycle, the ultrasonic measurement system (22) amplifies the electro-ultrasonic received signal (13) into an amplified ultrasonic received signal (15), and In the first transmission cycle, the ultrasonic measurement system (22) compares the value of the amplified ultrasonic received signal (15) with a second threshold (105), and The ultrasonic measurement system (22) detects a second time point (103) within the first transmission cycle of the short ultrasonic pulse train (504), at which time point (103), the amplitude (107) of the amplified ultrasonic received signal (15) is lower than the second threshold (105), and The ultrasonic measurement system (22) determines a first time difference (101) between the first time point (102) and the second time point (103), and The ultrasonic measurement system (22) transmits at least one long ultrasonic pulse train (505) during the second transmission cycle, and The second transmission cycle follows the first transmission cycle in time, and In the second transmission cycle, the ultrasonic measurement system (22) compares the value of the electro-ultrasonic received signal (13) with the first threshold, and The ultrasonic measurement system (22) detects a third time point (502) within the second transmission cycle of the long ultrasonic pulse train (505), at which time point (502) the value of the electro-ultrasonic received signal (13) is lower than the first threshold, and In the second transmission cycle, the ultrasonic measurement system (22) amplifies the electro-ultrasonic received signal (13) into an amplified ultrasonic received signal (15), and In the second transmission cycle, the ultrasonic measurement system (22) compares the value of the amplified ultrasonic received signal (15) with the second threshold (105), and as a result of the comparison, forms a second comparator output signal (28). The ultrasonic measurement system (22) starts the timer (41) at the third time point (502), and Wherein, if present, at the point in time when the timer (41) detects that a time interval corresponding to the first time difference (101) plus the lead time has elapsed since its start, the ultrasonic measurement system (22) detects the value of the amplitude (107) of the amplified ultrasonic received signal (15), and, The ultrasonic measurement system (22) compares the amplitude (107) of the amplified ultrasonic received signal (15) detected therefrom with the second threshold (105), and If the detected value of the amplitude (107) of the amplified ultrasonic received signal (15) is higher than the second threshold (105), the ultrasonic measurement system (22) infers that there is an object (11) in the vicinity of the ultrasonic sensor (1).

14. An ultrasonic measurement system (22), in, The ultrasonic measurement system (22) performs an evaluation method for the electro-ultrasonic received signal (13) of the piezoelectric oscillating element (8) of the ultrasonic transducer (9) of the ultrasonic sensor (1) for improving near-field detection, and In this process, the ultrasonic sensor (1) transmits at least one short ultrasonic pulse train (504) during the first transmission cycle, and In the first transmission cycle, the ultrasonic measurement system (22) compares the value of the electro-ultrasonic received signal (13) with a first threshold, and The ultrasonic measurement system (22) detects a first time point (102) within the first transmission cycle of the short ultrasonic pulse train (504), at which time point (102), the value of the electro-ultrasonic received signal (13) is lower than the first threshold, and In the first transmission cycle, the ultrasonic measurement system (22) amplifies the electro-ultrasonic received signal (13) into an amplified ultrasonic received signal (15), and In the first transmission cycle, the ultrasonic measurement system (22) compares the value of the amplified ultrasonic received signal (15) with a second threshold (105), and The ultrasonic measurement system (22) detects a second time point (103) within the first transmission cycle of the short ultrasonic pulse train (504), at which time point (103), the amplitude (107) of the amplified ultrasonic received signal (15) is lower than the second threshold (105), and The ultrasonic measurement system (22) transmits at least one long ultrasonic pulse train (505) during the second transmission cycle, and The second transmission cycle follows the first transmission cycle in time, and In the second transmission cycle, the ultrasonic measurement system (22) compares the value of the electro-ultrasonic received signal (13) with a first threshold, and The ultrasonic measurement system (22) detects a third time point (502) within the second transmission cycle of the long ultrasonic pulse train (505), at which time point (502) the value of the electro-ultrasonic received signal (13) is lower than the first threshold, and In the second transmission cycle, the ultrasonic measurement system (22) amplifies the electro-ultrasonic received signal (13) into an amplified ultrasonic received signal (15), and In the second transmission cycle, the ultrasonic measurement system (22) compares the value of the amplified ultrasonic received signal (15) with the second threshold (105), and The ultrasonic measurement system (22) detects a fourth time point (503) within the second transmission cycle of the long ultrasonic pulse train (505), at which time point (503), the amplitude (107) of the amplified ultrasonic received signal (15) is lower than the second threshold (105), and Based on the first time point (102), the second time point (103), the third time point (502), and the fourth time point (503), the ultrasonic measurement system (22) infers that an object (11) exists in the vicinity of the ultrasonic sensor (1).

15. The ultrasonic measurement system (22) according to claim 14, in, The ultrasonic measurement system (22) determines a first time difference (101) between the first time point (102) and the second time point (103), and The ultrasonic measurement system (22) infers the presence of an object (11) in the vicinity of the ultrasonic sensor (1) based on the first time difference (101), the third time point (502), and the amplitude (107) of the amplified ultrasonic received signal (15) at a time point later than the third time point (502) than the value of the first time difference (101).

16. The ultrasonic measurement system (22) according to claim 15, in, At a time point later than the third time point (502) by the value of the first time difference (101), when the value of the amplitude (107) of the amplified ultrasonic received signal (15) is greater than the second threshold (105), the ultrasonic measurement system (22) infers that there is an object (11) in the vicinity of the ultrasonic sensor (1).

17. The ultrasonic measurement system (22) according to claim 14, in, The ultrasonic measurement system (22) determines a first time difference (101) between the first time point (102) and the second time point (103), and Based on the first time difference (101), the third time point (502), and the fourth time point (503), the ultrasonic measurement system (22) infers that an object (11) exists in the vicinity of the ultrasonic sensor (1).

18. The ultrasonic measurement system (22) according to claim 17, in, The ultrasonic measurement system (22) determines a second time difference (501) between the third time point (502) and the fourth time point (503), and Based on the first time difference (101) and the second time difference (501), the ultrasonic measurement system (22) infers that an object (11) exists in the vicinity of the ultrasonic sensor (1).

19. The ultrasonic measurement system (22) according to claim 18, in, If the duration of the first time difference (101) is less than the duration of the second time difference (501) plus an optional positive delay, the ultrasonic measurement system (22) infers the presence of an object (11) in the vicinity of the ultrasonic sensor (1).

20. An ultrasonic measurement system (22), in, The ultrasonic measurement system (22) performs an evaluation method for the electro-ultrasonic received signal (13) of the piezoelectric oscillating element (8) of the ultrasonic transducer (9) of the ultrasonic sensor (1) for improving near-field detection, and The ultrasonic measurement system (22) transmits at least one short ultrasonic pulse train (504) during the first transmission cycle, and In the first transmission cycle, the ultrasonic measurement system (22) compares the value of the electro-ultrasonic received signal (13) with a first threshold, and The ultrasonic measurement system (22) detects a first time point (102) within the first transmission cycle of the short ultrasonic pulse train (504), at which time point (102), the value of the electro-ultrasonic received signal (13) is lower than the first threshold, and In the first transmission cycle, the ultrasonic measurement system (22) amplifies the electro-ultrasonic received signal (13) into an amplified ultrasonic received signal (15), and In the first transmission cycle, the ultrasonic measurement system (22) compares the value of the amplified ultrasonic received signal (15) with a second threshold (105), and The ultrasonic measurement system (22) detects a second time point (103) within the first transmission cycle of the short ultrasonic pulse train (504), at which time point (103), the amplitude (107) of the amplified ultrasonic received signal (15) is lower than the second threshold (105), and The ultrasonic measurement system (22) transmits at least one long ultrasonic pulse train (505) during the second transmission cycle, and The second transmission cycle follows the first transmission cycle in time, and In the second transmission cycle, the ultrasonic measurement system (22) compares the value of the electro-ultrasonic received signal (13) with the first threshold, and The ultrasonic measurement system (22) detects a third time point (502) within the second transmission cycle of the long ultrasonic pulse train (505), at which time point (502) the value of the electro-ultrasonic received signal (13) is lower than the first threshold, and In the second transmission cycle, the ultrasonic measurement system (22) amplifies the electro-ultrasonic received signal (13) into an amplified ultrasonic received signal (15), and In the second transmission cycle, the ultrasonic measurement system (22) compares the value of the amplified ultrasonic received signal (15) with the second threshold (105), and Based on the comparison results of the first time point (102), the second time point (103), the third time point (502), and the value of the amplified ultrasonic received signal (15) in the second transmission cycle with the second threshold (105), the ultrasonic measurement system (22) infers that there is an object (11) in the vicinity of the ultrasonic sensor (1).

21. The ultrasonic measurement system (22) according to claim 20, in, The ultrasonic measurement system (22) determines a first time difference (101) between the first time point (102) and the second time point (103), and The ultrasonic measurement system (22) infers the presence of an object (11) in the vicinity of the ultrasonic sensor (1) based on the first time difference (101), the third time point (502), and the amplitude (107) of the amplified ultrasonic received signal (15) at a time point later than the third time point (502) than the value of the first time difference (101).

22. The ultrasonic measurement system (22) according to claim 21, in, At a time point later than the third time point (502) by the value of the first time difference (101), when the value of the amplitude (107) of the amplified ultrasonic received signal (15) is greater than the second threshold (105), the ultrasonic measurement system (22) infers that there is an object (11) in the vicinity of the ultrasonic sensor (1).

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