Ultrasonic sensor chip and ultrasonic radar device

Abstract

The application provides an ultrasonic sensor chip and a radar device, and relates to the technical field of ultrasonic waves. The ultrasonic sensor chip comprises a first receiving end, a second receiving end, a first transmitting end and a second transmitting end, and a driving circuit and a signal processing circuit; the first receiving end is used for receiving a trigger signal and transmitting the trigger signal to the driving circuit; the driving circuit outputs a modulated wave composed of a plurality of opposite-phase signals through the first transmitting end; the first transmitting end is used for coupling to an ultrasonic transducer; the second receiving end is used for receiving an ultrasonic wave signal transmitted by the ultrasonic transducer and transmitting the ultrasonic wave signal to the signal processing circuit; the signal processing circuit performs correlation degree operation on the ultrasonic wave signal according to a reference signal, and outputs a feedback signal for indicating the appearance of a specified echo when the correlation degree reaches a preset value; and the feedback signal is outputted outward through the second transmitting end. The application reduces the adverse effects of interference, noise and the like in the environment on the ultrasonic wave signal processing, and improves accuracy.

Description

Technical Field

[0001] This application relates to the field of ultrasonic technology, and in particular to an ultrasonic sensor chip and an ultrasonic radar device. Background Technology

[0002] Currently, ultrasonic radar devices, such as those used in vehicles, are employed to determine the distance between vehicles and obstacles. These devices both emit and receive ultrasonic signals, dividing the received signal into time segments, each roughly half the length of a burst. Within each time segment, a peak value is identified, and the distance between the vehicle and the obstacle is determined based on this peak signal. However, environmental clutter, noise, and other ultrasonic waves can interfere with ultrasonic systems, rendering existing solutions ineffective in assessing obstacle distances. Summary of the Invention

[0003] An ultrasonic sensor chip and an ultrasonic radar device are provided, which can reduce environmental interference with ultrasonic signal processing.

[0004] In a first aspect, an ultrasonic sensor chip is provided, comprising a first receiving end, a second receiving end, a first transmitting end, and a second transmitting end, as well as a driving circuit and a signal processing circuit; the first receiving end is used to receive a trigger signal and transmit the trigger signal to the driving circuit, the driving circuit outputs a modulated wave composed of a plurality of signals with opposite phases through the first transmitting end, the first transmitting end being used to couple to an ultrasonic transducer; the second receiving end is used to receive an ultrasonic signal transmitted from the ultrasonic transducer and transmit the ultrasonic signal to the signal processing circuit; the signal processing circuit performs correlation calculation on the ultrasonic signal according to a reference signal, and outputs a feedback signal indicating the occurrence of a specified echo when the correlation reaches a preset value, the feedback signal being output outward through the second transmitting end.

[0005] In a second aspect, an ultrasonic radar device is provided, comprising: the ultrasonic sensor chip described above; and an ultrasonic transducer; wherein the ultrasonic transducer is electrically connected to a first transmitting end to receive the modulated wave and to transmit an ultrasonic signal according to the modulated wave; and the ultrasonic transducer is also electrically connected to a second receiving end to transmit the received ultrasonic signal to the signal processing circuit.

[0006] The ultrasonic sensor chip and ultrasonic radar device in this application embodiment modulate the carrier wave using a modulation code to generate a modulated wave for exciting ultrasonic wave transmission. A correlation calculation module calculates the correlation of the received signal and determines whether it is a specified echo based on the calculation result. This reduces the adverse effects of environmental interference and noise on ultrasonic signal processing, thereby improving the accuracy of ultrasonic signal processing. For example, when the ultrasonic sensor is applied to an ultrasonic radar device in a vehicle, it can improve the accuracy of radar positioning. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of the structure of an ultrasonic radar device and an obstacle in an embodiment of this application;

[0008] Figure 2 This is a waveform diagram of the phase modulation process in an embodiment of this application;

[0009] Figure 3 A schematic diagram illustrating the principle of phase modulation in the embodiments of this application;

[0010] Figure 4 This is a schematic diagram of the spectral changes of the carrier before and after phase modulation in an embodiment of this application;

[0011] Figure 5 for Figure 1 A schematic diagram of a portion of the structure in a medium-speed ultrasonic radar device;

[0012] Figure 6 This is a schematic diagram showing the spectral changes of a signal consisting only of a modulated wave received by the second ultrasonic transducer in this embodiment before and after modulation and despreading.

[0013] Figure 7 This is a schematic diagram showing the spectral changes of the signal, including the modulated wave and interference, received by the second ultrasonic transducer in this embodiment before and after modulation and despreading.

[0014] Figure 8 for Figure 1 Another structural diagram of a part of the ultrasonic radar device;

[0015] Figure 9 This is a schematic diagram illustrating the correlation between the carrier wave and the sampled signals received at different times in an embodiment of this application;

[0016] Figure 10 This is a schematic diagram of waveform sampling in an embodiment of this application;

[0017] Figure 11 for Figure 1 A schematic diagram of a portion of the structure in a medium-speed ultrasonic radar device;

[0018] Figure 12 for Figure 1 A schematic diagram of a portion of the structure in a medium-speed ultrasonic radar device;

[0019] Figure 13 This is a schematic diagram of sampling waveforms of different amplitudes in an embodiment of this application;

[0020] Figure 14a for Figure 1 A schematic diagram of a portion of the structure in a medium-speed ultrasonic radar device;

[0021] Figure 14b for Figure 1 A schematic diagram of a portion of the structure in a medium-speed ultrasonic radar device;

[0022] Figure 15 for Figure 1 A schematic diagram of a portion of the structure in a medium-speed ultrasonic radar device;

[0023] Figure 16 This is a schematic diagram illustrating the relationship between correlation and modulation code in one embodiment of this application;

[0024] Figure 17 This is a flowchart illustrating a signal processing method according to an embodiment of this application;

[0025] Figure 18 This is a flowchart illustrating another signal processing method in an embodiment of this application;

[0026] Figure 19 This is a flowchart illustrating another signal processing method in an embodiment of this application;

[0027] Figure 20 This is a flowchart illustrating another signal processing method in an embodiment of this application;

[0028] Figure 21 This is a flowchart illustrating another signal processing method in an embodiment of this application;

[0029] Figure 22 This is a flowchart illustrating another signal processing method in an embodiment of this application. Detailed Implementation

[0030] The terminology used in the implementation section of this application is for the purpose of explaining specific embodiments of this application only, and is not intended to limit this application.

[0031] This application provides an ultrasonic sensor chip and an ultrasonic radar device. The ultrasonic sensor chip can be applied in an ultrasonic radar device, such as... Figure 1As shown, the ultrasonic radar device 100 includes an ultrasonic sensor chip 10 and an ultrasonic transducer 200. The ultrasonic transducer 200 includes a first ultrasonic transducer 201 and a second ultrasonic transducer 202. The first ultrasonic transducer 201 is used to emit ultrasonic waves, and the second ultrasonic transducer 202 is used to receive ultrasonic waves. It should be noted that the first ultrasonic transducer 201 and the second ultrasonic transducer 202 can be two independent devices or integrated together. The ultrasonic sensor chip 10 includes: a carrier generation module 1 for generating a carrier wave; a modulation code generation module 2 for generating a modulation code; and a phase modulation module 3. The input terminal of the phase modulation module 3 is electrically connected to the output terminal of the carrier generation module 1 and the output terminal of the modulation code generation module 2. The output of block 3 is electrically connected to the first ultrasonic transducer 201. The phase modulation module 3 is used to perform phase modulation on the carrier wave according to the modulation code to obtain a modulated wave, and output the modulated wave to the first ultrasonic transducer 201. The sampling module 4 has its input electrically connected to the second ultrasonic transducer 202. The sampling module 4 is used to sample the ultrasonic signal received by the second ultrasonic transducer 202 to obtain a sampled signal. The correlation calculation module 5 has its input electrically connected to the output of the sampling module 4. The correlation calculation module 5 is used to determine the correlation of the sampled signal according to the reference signal. The correlation is related to the modulation code and the carrier wave. The processing module 6 is used to determine the sampled signal with a correlation reaching a preset value as a specified echo. The ultrasonic radar device 100 may also include a microprocessor chip 20, which is electrically connected to the ultrasonic sensor chip 10. The microprocessor chip 20 is used to trigger the ultrasonic sensor chip 10 to generate a modulated wave, and also to receive data returned from the ultrasonic sensor chip 10.

[0032] Specifically, at least one pin of the ultrasonic sensor chip 10 is electrically connected to the ultrasonic transducer 200. This pin is also electrically connected to the microprocessor chip 20 via a Controller Area Network (CAN), Local Interconnect Network (LIN), or Point-to-Point (pt-to-pt) connection. When ultrasonic detection is required, the microprocessor chip 20 outputs a trigger signal to the ultrasonic sensor chip 10. Responding to the trigger signal, the ultrasonic sensor chip 10 drives the carrier generation module 1 to generate a carrier wave (e.g., a sine wave). Additionally, the modulation code generation module 2 generates a modulation code as a modulation signal. The phase modulation module 3 modulates the phase of the carrier wave according to the modulation code, obtaining a modulated wave. In other words, the phase of the carrier wave is adjusted according to the modulation code, and the adjusted signal is the modulated wave, which is the ultrasonic excitation signal. The phase modulation module 3 outputs the modulated wave to the first ultrasonic transducer 201. Under the excitation and control of the modulated wave, the first ultrasonic transducer 201 vibrates to generate corresponding ultrasonic waves. These ultrasonic waves are reflected when they encounter obstacles. The second ultrasonic transducer 202 receives ultrasonic signals. The sampling module 4 samples the ultrasonic signals received by the second ultrasonic transducer 202 to obtain a sampled signal. For example, the sampling module 4 is an analog-to-digital converter (ADC) that converts the analog signal into a digital signal. Because of interference and noise in the environment, and the possibility of ultrasonic waves generated by other ultrasonic transducers, the wave received by the second ultrasonic transducer 202 may not necessarily be the ultrasonic wave emitted by the first ultrasonic transducer 201. In this embodiment, the ultrasonic wave emitted by the first ultrasonic transducer 201 is generated based on a modulated wave driven by a modulation code. This ultrasonic wave not only has the signal characteristics of the carrier wave itself but also the signal characteristics of the modulation code. Therefore, for the ultrasonic signal received by the second ultrasonic transducer 202, after sampling, the correlation calculation module 5 determines the correlation based on the reference signal and the sampled signal. If the processing module 6 determines that the correlation reaches a preset value, it indicates that the signal simultaneously possesses the characteristics of a carrier wave and a modulation code, meaning that the signal originates from the first ultrasonic transducer 201 and is not an interference or noise signal. Therefore, this signal is used as the designated echo, which refers to the echo signal of the ultrasonic wave emitted by the first ultrasonic transducer 201, to facilitate subsequent determination of the distance to the obstacle based on the designated echo. If the processing module 6 determines that the correlation does not reach the preset value, it indicates that the signal is an interference or noise signal and will not be used as the designated echo. In the subsequent process of determining the distance to the obstacle, this reduces interference and noise, improving the accuracy of ultrasonic positioning.

[0033] In automobiles, microprocessor chips are commonly referred to as Electronic Control Units (ECUs) or domain controllers. Examples include Microcontroller Units (MCUs), Digital Signal Processing (DSPs), Microprocessor Units (MPUs), and Micro Central Processing Units (CPUs), which are miniature central control chips or system-on-a-chips capable of processing digital and analog signals, or performing signal control, instruction processing, and computation functions.

[0034] The ultrasonic sensor chip in this embodiment modulates a carrier wave using a modulation code to generate a modulated wave for exciting ultrasonic wave transmission. A correlation calculation module calculates the correlation of the received signal and determines whether it is a specified echo based on the calculation result. This reduces the adverse effects of environmental interference and noise on ultrasonic signal processing, thereby improving the accuracy of ultrasonic signal processing. For example, when the ultrasonic sensor chip is applied to an ultrasonic radar device in a vehicle, it can improve the accuracy of radar positioning.

[0035] In one possible implementation, the ultrasonic sensor chip 10 further includes a first timer, which can be electrically connected to the processing module 6. The first timer is used to start timing when the first ultrasonic transducer 201 emits an ultrasonic signal, or when a trigger signal sent by the microprocessor chip 20 is received, and to stop timing when a specified echo is received. The ultrasonic sensor chip 10 is also used to calculate the obstacle distance based on the timing duration of the first timer and the specified echo, and to transmit the obstacle distance to the microprocessor chip 20. The processing module 6 in the ultrasonic sensor chip 10 can calculate the obstacle distance based on the relationship between time and ultrasonic transmission speed. After obtaining the distance information, the processing module 6 outputs data to the microprocessor chip 20. The microprocessor chip 20 is used to make a judgment based on the received data and trigger a prompt, such as triggering a buzzer to emit a prompt sound, a light prompt, a display prompt, or a voice prompt.

[0036] In one possible implementation, the microprocessor chip 20 may include a first timer. The microprocessor chip 20 is also used to calculate the distance to the obstacle based on the duration of the first timer and a feedback signal from the ultrasonic sensor chip 10 indicating that a specified echo has been received. That is, the first timer may also be located within the microprocessor chip 20. The timer starts counting after the microprocessor chip 20 sends a trigger signal, which triggers the ultrasonic sensor chip 10 to generate a modulated wave, causing the first ultrasonic transducer 201 to emit an ultrasonic signal. The timer stops counting when the specified echo is received, and the distance to the obstacle can be calculated based on the relationship between time and the speed of ultrasonic wave transmission. After obtaining the distance information, a corresponding action is taken, such as triggering a buzzer to sound an alarm or triggering an alarm light.

[0037] In other words, in an ultrasonic radar device, the distance to an obstacle can be calculated using either the ultrasonic sensor chip 10 or the microprocessor chip 20. For example, after determining a specified echo, the ultrasonic sensor chip 10 sends a feedback signal to the microprocessor chip 20 indicating that the specified echo has been received, such as the I / O pin clock being high or low. After determining the specified echo, the ultrasonic sensor chip 10 pulls the I / O pin high or low. The microprocessor chip 20 calculates the time from sending a trigger signal to receiving the indication signal based on this signal, calculates the distance to the obstacle, and then controls the corresponding prompting system to take action. If the ultrasonic sensor chip 10 performs the distance calculation, it can send data indicating different distances through the I / O pin after the calculation is completed. The microprocessor chip 20 receives and parses this data, and controls the corresponding prompting system to take action based on the parsing result.

[0038] In one possible implementation, such as Figure 2 and Figure 3 As shown, the modulation code includes a first code value and a second code value. For example, the first code value is 0 and the second code value is 1. During the modulation process, the first code value is used to flip the carrier phase by 180°, and the second code value is used to keep the carrier phase unchanged.

[0039] Specifically, the modulation code comprises multiple modulation chips, each with a width of d, and one carrier period corresponds to one modulation chip width. For example, Figure 2The carrier wave is wave A with 9 sinusoidal periods; the modulation code is 111001100, which is wave B with 9 modulation chips. During the modulation of the carrier wave according to the modulation code, when wave A encounters a modulation chip with a value of 0, the sine wave phase flips by 180°; when it encounters a modulation chip with a value of 1, the sine wave phase remains unchanged. The resulting modulated wave is wave C. That is, wave C = wave A * wave B, or wave A(111111111) * wave B(111001100) = wave C(111001100). Here, "*" means that the carrier wave remains unchanged when encountering a modulation chip with a value of 1, and flips its phase when encountering a modulation chip with a value of 0. Assuming the initial phase sequence code of wave A is 1, and the phase-flipped sequence code is 0, the sequence code of wave C after modulation is 111001100. After the phase modulation described above, although the carrier's driving frequency remains unchanged, the phase-modulated carrier produces a spread spectrum effect. For example... Figure 4 As shown, before phase modulation, the carrier has only one frequency, and after modulation, multiple frequencies are generated, which is equivalent to the frequency being scattered. It should be noted that this scheme does not adjust the carrier frequency, but only adjusts the carrier phase, but produces the effect of frequency modulation, which is a significant improvement over frequency modulation, as described below.

[0040] Furthermore, the width of a chip does not necessarily correspond to one carrier cycle; it can also correspond to multiple carrier cycles. The principle is the same as above, where the width of a chip equals one carrier cycle, and will not be repeated here. Other descriptions regarding chip width are provided below.

[0041] In one possible implementation, such as Figure 5 As shown, the ultrasonic sensor chip 10 further includes: a modulation and despreading module 8 disposed between the sampling module 4 and the correlation calculation module 5. For example, the input terminal of the modulation and despreading module 8 is electrically connected to the output terminal of the sampling module 4. The modulation and despreading module 8 is used to modulate and despread the sampling signal according to the modulation code to obtain the despread sampling signal; the input terminal of the correlation calculation module 5 is electrically connected to the output terminal of the modulation and despreading module 8. The correlation calculation module 5 is used to calculate the correlation between the despread sampling signal and the reference signal. The reference signal is a carrier wave or a carrier-orthogonal wave orthogonal to the carrier wave.

[0042] Specifically, the sampling module 4 samples the ultrasonic signal received by the second ultrasonic transducer 202 to obtain a modulated wave, D. The modulation and despreading module 8 modulates and despreads wave D according to wave B, obtaining a despread sampled signal, E. The modulation and despreading process is the same as the modulation process, i.e., wave E = wave D * wave B. Figure 6As shown, if the signal received by the second ultrasonic transducer 202 only contains the modulated wave, wave D is equivalent to wave C, then wave E = wave C * wave B. Since the sequence code for wave C is 111001100 and wave B is 111001100, then wave E = wave C * wave B = 111111111. The formula for calculating the correlation is: correlation value f = ∑M * N = M1 * N1 + M2 * N2 + ... + Mn * Nn (convolution operation), where M = (M1, M2, ..., Mn), and N = (N1, N2, ..., Nn). The correlation between the time sequence corresponding to the despread sampled signal (wave E) and the carrier (wave A) is f = ∑wave E * wave A. Since wave E equals wave A, the correlation value is very high when performing correlation calculations on two identical waves (e.g., 9 in the example).

[0043] like Figure 7 As shown, if the signal received by the second ultrasonic transducer 202 includes the specified echo itself (i.e., the modulated wave of the spread spectrum), interference signals in the environment, channel noise, or spread spectrum signals emitted by other devices, the interference signals in the environment, channel noise, or spread spectrum signals emitted by other devices are called non-specified echoes. There are two types of non-specified echoes: one is a spread spectrum signal, which contains signals of multiple frequencies, and the other is a signal with a particularly high frequency, i.e., a single-frequency signal. Here, we will take the example where the received interference signal is a single-frequency signal and the other signals are spread spectrum signals for explanation.

[0044] To better understand, here's an example:

[0045] For example, a single-frequency sequence of an interference signal, denoted as wave D1, where wave D1 = 111111111111111111 (a double harmonic of the carrier frequency), is modulated and despread. The resulting signal after modulation and despreading is wave E1, where wave E1 = wave D1 * wave B. A correlation calculation between wave E1 and wave A yields a very low or low correlation value (e.g., less than or equal to 6 in this example). Even as wave D1 slides, the correlation between wave E1 and wave A remains very low after sliding despreading with the modulation code wave B. The approximate principle of sliding despreading is as follows: the first 9 bits of D1 modulated and despread with wave B yield E1 = 111001100; the 2nd to 10th bits of D1 modulated and despread with wave B yield E1 = 111001100; the 3rd to 11th bits of D1 modulated and despread with wave B yield E1 = 111001100, and so on, until D1 has moved completely. The correlation between wave E1 and wave A is calculated one by one to examine the correlation between wave E1 and wave A during any sliding process. When wave E1 and wave A are different, the correlation remains at a low level throughout the entire sliding process.

[0046] For example, if the interference signal is a single-frequency sequence, denoted as wave D2, and wave D2 = 111111111 (the same as the carrier frequency), then wave E2 = wave D2 * wave B = 111001100. When wave E2 is correlated with wave A, the correlation value is very low (as shown in the example, the highest is 5). Therefore, even if the received echo signal is consistent with the carrier, it does not conform to the modulation rules of the modulation code, and the final correlation value is still very low, and it is not the specified echo.

[0047] For example, if other interference signals are spread spectrum sequences, denoted as D3, and wave D3 = 111000110, then wave E3 = wave D3 * wave B = 111110110. When wave E3 and wave A are correlated, the correlation value is low (as shown in the example, the highest is 6). This shows that even if the received echo signal is also a signal containing multiple frequencies, it does not conform to the modulation rules of the modulation code, and the final correlation is still very low, indicating that it is not the specified echo. It should be noted that all echoes undergo sliding despreading. If there are signals before and after a corresponding wave, the corresponding wave signal is selected and modulated / despread with wave B. For example, if a signal contains waves D1, D2, and D3 in chronological order, the first 9 bits of D1 are modulated / despread with wave B, and the modulated / despread signal is output to the next node. This process continues, modulating / despreading the 2nd to 10th bits of D1 with wave B, and so on. After the 10th to 18th bits of D1 are modulated / despread with wave B, the 11th to 18th bits of D1 and the 1st bit of D2 are modulated / despread with wave B, and the 12th to 18th bits of D2 are modulated / despread with wave B. Bits 1-2 of D2 are modulated and despread with wave B... After bits 1-9 of D2 are modulated and despread with wave B, bits 2-9 of D2 and bit 1 of D3 are modulated and despread with wave B, bits 3-9 of D2 and bits 1-2 of D3 are modulated and despread with wave B... After bits 1-9 of D3 are modulated and despread with wave B, if there is no signal afterward, the amount of data modulated and despread by D3 with wave B decreases, bits 2-9 of D3 are modulated and despread with wave B, bits 3-9 of D3 are modulated and despread with wave B... until the number of bits of D3 and wave B have no overlap and cannot be modulated and despread.

[0048] Therefore, it can be seen that if the ultrasonic signal received by the second ultrasonic transducer 202 contains a modulated wave, then after despreading, a wave with the same frequency as the carrier wave will be obtained; if the ultrasonic signal received by the second ultrasonic transducer 202 contains other non-specified echoes, then after the despreading process, both single-frequency signals and spread-spectrum signals will be spread again (i.e., broken up), thus a wave with the same frequency as the carrier wave will not be obtained. Figure 7 As shown, the embodiments of this application can determine whether a signal is an interference signal, with excellent accuracy, precision, and recognition performance.

[0049] In one possible implementation, such as Figure 8 As shown, the reference signal is a modulated wave or a modulated orthogonal wave orthogonal to the modulated wave. For example, the input terminal of the correlation calculation module 5 is electrically connected to the output terminal of the sampling module 4.

[0050] Specifically, in Figure 8 In the structure shown, the correlation between the sampled signal and the modulated wave can be directly calculated to determine whether the signal received by the second ultrasonic transducer 202 is the same signal emitted by the first ultrasonic transducer 201. For example, if wave C = 111001100, and since wave C = wave A * wave B, the correlation calculation between wave D and wave C is equivalent to calculating the correlation between wave A * wave B and wave D, i.e., calculating wave A * wave B * wave D = wave A * (wave B * wave D). Performing the correlation calculation between wave D and wave C is equivalent to including the despreading process in the above scheme, as detailed above. Only the correlation calculation will be discussed here.

[0051] As shown above, the correlation value f = wave A * (wave B * wave D) = 111111111 * (111001100 * wave D).

[0052] For example, if wave D1 = 1111111111111111111, and wave B * wave D = 111001100, then the correlation value f1 = 111111111 * 111001100, which is a very low correlation value (the highest being 5 in the example).

[0053] For example, wave D2 = 111111111, wave B * wave D = 111001100, correlation value f2 = 111111111 * 111001100, the correlation value is very low (as in the example, the highest is 5);

[0054] For example, wave D3 = 111000110, wave B * wave D = 111110101, correlation value f3 = 111111111 * 111110101, the correlation value is low (as in the example, the highest is 7);

[0055] For example, wave D4 = 111001100, wave B * wave D = 111111111, the correlation value f4 = 111111111 * 111111111, the correlation value is the highest (9 in the example).

[0056] therefore, Figure 8 The embodiment corresponding to the structure shown can also determine whether a signal is an interference signal. Directly using the modulated wave and the sampled signal to perform correlation calculations reduces the modulation and despreading process of the sampling chip, resulting in a simpler hardware circuit and a more streamlined connection between circuits. In the aforementioned patent, the correlation calculation module includes a convolution operation logic circuit to calculate the correlation.

[0057] In one possible implementation, the ultrasonic sensor chip 10 may also include a second timer. This second timer is related to a preset correlation value. As time increases, the ultrasonic echo signal weakens, and the preset correlation value decreases accordingly. That is, the preset value includes multiple different values. Alternatively, the second timer may not be included; the preset correlation value is time-related and is directly stored in memory. The memory contains multiple different values ​​used to indicate the preset value. As the clock advances, preset values ​​at different addresses in the memory are read. These preset values ​​are time-related, and generally, they decrease as the clock advances. Furthermore, the memory may also store data relating time and the preset value. By reading the time and the preset value, the correlation can be calculated. The memory used to store the preset value may be the same memory module as the memory module 81 described below, but at a different address, or it may be a memory module independent of the memory module 81 described below. However, whether it is the same memory module or an independent memory module is merely a physical division.

[0058] After a time-dependent correlation preset value is set, the storage module should also be electrically connected to the processing module 6. The processing module 6 reads the preset value information in the storage module, compares the correlation information output by the correlation calculation module with the preset value, and thus determines whether the specified echo exists.

[0059] The technical effects of the embodiments of this application will be further described below, for example in Figure 8 In the embodiment corresponding to the structure shown, the correlation between the despread sampled signal (wave E) and the modulated wave (wave C) is used to determine whether the despread sampled signal (wave E) originates from the ultrasonic wave emitted by the first ultrasonic transducer 201. For example... Figure 9 As shown, the despread sampled signal (wave E) contains a specified echo. During transmission or sliding, the echo signal is not time-aligned with the modulated wave (wave C), then gradually aligns, and then gradually moves away from alignment. For example:

[0060] The timing of the despread sampled signal (wave E) and the modulated wave (wave C) is not aligned due to the clock lengths t0 and t1, resulting in low correlation.

[0061] With a clock length of t2, the despread sampled signal (wave E) and the modulated wave (wave C) are aligned in timing, resulting in the highest correlation.

[0062] The timing of the despread sampled signal (wave E) and the modulated wave (wave C) is not aligned due to the clock lengths t3 and t4, resulting in low correlation.

[0063] Therefore, a high correlation is only achieved when the timing corresponding to the specified modulation wave (wave C) is present and the phases are aligned; otherwise, the correlation is low. If the sequence is long enough, the correlation will generally not rise from low to high and then fall back down. Even if it does occur, the correlations at the two ends with the highest correlation are very low and easily distinguishable from the highest correlation. In other words, in this embodiment, the moment when the specified echo is received can be determined more accurately, thus improving the accuracy of obstacle distance calculation based on the clock length of the received specified echo.

[0064] As explained above, by modulating the carrier wave with phase and then adjusting its phase to achieve a spread spectrum effect, followed by despreading the echo signal, only echo signals that meet the modulation and despreading rules can achieve a high correlation, i.e., reaching the preset correlation value. Any other non-spread echo signals will be respread during the despreading process, thus failing to obtain a high correlation value. The correlation value is used to determine whether a specified echo has appeared. Due to phase adjustment, any echo that does not meet the rules in any part will have a relatively low correlation value. Therefore, only echo signals with high correlation values ​​are considered specified echo signals. By determining the specified echo signals, the adverse effects of environmental interference and noise on ultrasonic signal processing can be reduced, thereby improving the accuracy of ultrasonic signal processing.

[0065] Furthermore, compared to existing technologies, the embodiments of this application also have the following beneficial effects:

[0066] 1) The timing of echo occurrence can be clearly specified, and the judgment logic is relatively simple. In existing correlation calculations, when performing correlation calculations between locally stored signals and received signals, the correlation generally goes through a process from low to high and then from high to low. Therefore, the logic for selecting which correlation value to use as the timing of the echo signal occurrence is quite complex. This solution provides a clearer timing for the echo signal occurrence, simplifying the judgment logic. If the carrier wave length is long enough, the correlation will only be high when a specified echo waveform appears; other waveforms will have very low correlations because the probability of highly consistent waves emitted by nature or other ultrasonic systems is very low.

[0067] 2) Through the embodiments of this application, a filtering circuit (before or after sampling) is not required because the wave received by the second ultrasonic transducer 202 in this embodiment is not a single-frequency echo. Therefore, there is no need to add a filter to filter out irrelevant waves. Irrelevant waves will be filtered out during correlation calculation, without affecting the final result, thus saving hardware circuit overhead.

[0068] 3) In this embodiment, the carrier phase is changed without altering the frequency. Therefore, the sampling frequency can be fixed during sampling, and a relatively low frequency can be used. If the frequency is adjusted, increasing the frequency necessitates increasing the sampling frequency to reflect the true waveform. This requires either real-time adjustment of the sampling frequency or fixing a higher sampling frequency, which increases hardware overhead. Fixing a higher sampling frequency also increases the amount of data processed in subsequent correlation and peak calculations, further increasing hardware circuitry overhead. In this embodiment, only a relatively low frequency that reflects the carrier waveform needs to be fixed, simplifying the hardware.

[0069] 4) In addition, it has strong anti-interference capabilities, allowing multiple devices to work simultaneously. Due to the anti-interference capabilities of spread spectrum, multiple devices using unrelated spreading code sequences can work simultaneously without interfering with each other.

[0070] 5) The embodiments of this application can also effectively improve the impact of aftershocks, thereby improving the accuracy of obstacle detection. When the first and second ultrasonic transducers are the same sensor, after the ultrasonic sensor emits ultrasonic waves, the ultrasonic excitation signal stops. However, since the ultrasonic sensor cannot stop immediately, aftershocks will occur. During the aftershocks, obstacles cannot be detected, resulting in a decrease in detection accuracy, i.e., close-range detection is affected. The inventors have found that since the amplitude and frequency of aftershock vibrations change over time, as described in the embodiments of this application, a high correlation cannot be obtained. Therefore, even when the first and second ultrasonic transducers are the same sensor, the presence of aftershocks does not significantly affect the detection of the specified echo, thereby improving detection accuracy. Moreover, existing solutions for aftershocks generally employ additional aftershock cancellation circuits, such as increasing the conduction resistance to ground or adding suppression signals. These additional methods increase the complexity of the circuit and the entire chip. This application, however, does not require additional processing circuits, saving hardware costs and simplifying the circuit.

[0071] Regarding point 2) above, the fact that a filter circuit can be omitted is one of the beneficial effects of this application, but this application does not exclude the option of adding a filter circuit.

[0072] like Figure 10 As shown, sampling may not be performed at the ideal phase angle, resulting in a certain phase angle offset. For example, ideally, one point may be sampled at 0°, 90°, 180°, and 270°, but in reality, sampling may occur at 20°, 110°, 200°, and 290°, which will lead to a deviation in the final correlation result and thus misjudgment.

[0073] For example, if a sine wave is sampled at four points with an amplitude of 1V, then the values ​​obtained from sampling at 0°, 90°, 180°, and 270° are 0V, 1V, 0V, and -1V respectively (if this pattern appears, it is considered that a sine wave with the initial phase angle described above has appeared; similarly, if -1V, 0V, 1V, and 0V appear, it is considered that a sine wave with phase reversal as described above has appeared). If 0V, 1V, 0V, and -1V; 0V, 1V, 0V, and -1V; or -1V, 0V, 1V, and 0V appear, it indicates that a wave with an amplitude of 110° has appeared.

[0074] To simplify the explanation, such as Figure 10 As shown in Table 1, the waveforms in the attached figure show a wave of 110, indicating the presence of the specified echo. Ideally, sampling should begin at 0° (waveform 1). However, if sampling begins at 30° (waveform 2), 45° (waveform 3), and 90° (waveform 4), the resulting waveform data will differ. Taking a period of 4 clock cycles as an example, a low correlation is observed at 45° sampling, while the correlation is 0 at 90° sampling. In such cases, this result would be excluded, leading to the assumption that the specified echo did not appear, resulting in an incorrect judgment.

[0075] Table 1

[0076]

[0077] Therefore, in order to improve the problem of misjudgment caused by sampling phase angle deviation, in one possible implementation, such as Figure 11 As shown, the correlation calculation module 5 is specifically used to calculate the first correlation between the timing sequence corresponding to the sampled signal and the reference signal; calculate the second correlation between the orthogonal timing sequence corresponding to the sampled signal and the reference signal; and determine the sampled signal whose sum of the first correlation and the second correlation reaches a preset value as the specified echo.

[0078] For example, if the timing sequence corresponding to the carrier is 0, 1, 0, -1, 0, 1, 0, -1, 0, -1, 0, 1, then the orthogonal timing sequence corresponding to the carrier is 1, 0, -1, 0, 1, 0, -1, 0, -1, 0, 1, 0, and ∑ the timing sequence corresponding to the carrier * the orthogonal timing sequence corresponding to the carrier = 0, as shown in Table 2.

[0079] Table 2

[0080]

[0081]

[0082] Let's take the data of wave 1, wave 2, wave 3, and wave 4 with sampling angles of 0°, 30°, 45°, and 90° as examples for further explanation. See Tables 3-1 and 3-2 for details. Correlation 1 is the correlation between the carrier and wave n, and correlation 2 is the correlation between the orthogonal timing sequence corresponding to the carrier and wave n, where wave n is 1, 2, 3, or 4.

[0083] Table 3-1

[0084]

[0085] Table 3-2

[0086]

[0087] Therefore, regardless of the sampling phase angle, the sum of the first correlation (obtained by correlation calculation between the despread sampled signal and the carrier's corresponding time sequence) and the second correlation (obtained by correlation calculation between the despread sampled signal and the carrier's corresponding orthogonal time sequence) remains constant, which is 6 in the example. Thus, this improves the problem of misjudgment caused by sampling phase angle deviation.

[0088] In one possible implementation, such as Figure 12 As shown, before the above correlation calculation, the modulation and despreading module can be omitted, and the correlation calculation can be performed directly on the signal output by the sampling module 4. Figure 12 The scheme shown is the same as Figure 11 The proposed solutions are similar, the difference being that... Figure 11 The scheme shown calculates the correlation of the despread sampled signals. Figure 12 In the scheme shown, the correlation of the sampled signal output by the sampling module 4 is calculated. However, the principles of the two are similar. They both use the correlation calculation of orthogonal timing to improve the misjudgment problem caused by sampling phase deviation.

[0089] Because the farther the obstacle is from the ultrasonic system, the longer the ultrasonic wave travels, the amplitude of the ultrasonic signal received by the second ultrasonic transducer 202 will decrease as time increases. For example, as... Figure 13As shown, the solid waveform represents the ultrasonic signal received by the second ultrasonic transducer 202 when the time from the emission of the ultrasonic signal by the first ultrasonic transducer 201 to the receipt of the ultrasonic signal by the second ultrasonic transducer 202 is 0 seconds. Its amplitude is the same as the ultrasonic signal emitted by the first ultrasonic transducer 201 (in reality, it cannot be 0 seconds). The dashed waveform in the middle represents the ultrasonic signal received by the second ultrasonic transducer 202 at a time of 5 ms. The dashed waveform closest to the origin represents the ultrasonic signal received by the second ultrasonic transducer 202 at a time of 10 ms. Therefore, it can be seen that the later the time of the ultrasonic signal received by the second ultrasonic transducer 202, the lower the correlation with the carrier or modulated wave after calculation. Thus, a dynamic correlation threshold can be set. This correlation is time-dependent and decreases as time increases. That is, the preset value of the correlation can be negatively correlated with the timing of the second timer using the aforementioned second timer (or by directly storing a time-dependent preset value). However, setting a dynamically changing threshold requires more registers, memory, or more hardware circuitry overhead.

[0090] Therefore, this application also provides another solution to improve the problem of inaccurate judgment caused by the decrease in the amplitude of ultrasonic signals over time.

[0091] In one possible implementation, such as Figure 14a As shown, the aforementioned ultrasonic sensor chip further includes a symbol processing module 7 disposed between the sampling module 4 and the correlation calculation module 5. The symbol processing module 7 is used to convert positive values ​​of the sampled signal into a first fixed value and negative values ​​of the sampled signal into a second fixed value. For example, the symbol processing module 7 can be located between the correlation calculation module 5 and the modulation / despreading module 8. For 0V in the despread sampled signal, it remains unchanged and is still taken as 0V. If it is a negative value such as -1V, -0.707V, or -0.5V, the first fixed value is taken, such as -1V. If it is a positive value such as 1V, 0.707V, or 0.5V, the second fixed value is taken, such as 1V, similar to normalization processing. In this way, regardless of the sampled value, after processing by the symbol processing module, the output is independent of the amplitude.

[0092] As shown in Tables 4-1 and 4-2, it is in Figure 11 The illustrated scheme does not include correlation calculations for symbol extraction. Taking 0° phase angle sampling as an example, Tables 4-1 and 4-2 show how the sampling amplitude decreases over time, such as 1V—0.7V—0.5V—0.3V (maximum value). Therefore, the correlation calculation between the timing sequence corresponding to the carrier and the orthogonal timing sequence corresponding to the carrier also decreases, from 6—4.2—3—1.8. This necessitates adjusting the dynamic correlation value, resulting in high hardware overhead, complex circuitry, and even more complex logical operations.

[0093] Table 4-1

[0094]

[0095]

[0096] Table 4-2

[0097]

[0098] As shown in Tables 5-1 and 5-2, the positive and negative values ​​are processed by the sign processing module. Figure 14a As shown in the embodiments of this application, the sampled values ​​used for calculation remain unchanged as time increases; therefore, the sum of correlations is independent of time. This results in significant savings in hardware circuitry, reduced chip area, lower cost, and simpler logic operations.

[0099] Table 5-1

[0100]

[0101]

[0102] Table 5-2

[0103]

[0104] In one possible implementation, Figure 14b for Figure 14a In a variation, the symbol processing module 7 can also be positioned between the sampling module 4 and the modulation / despreading module 8. The symbol processing module 7 converts positive values ​​of the sampled signal into a first fixed value, converts negative values ​​of the sampled signal into a second fixed value, and outputs the converted sampled signal to the modulation / despreading module 8. This scheme is similar to... Figure 14a The proposed solutions are similar, the difference being that... Figure 14a In the scheme shown, the symbol extraction is the modulated and despread signal. Figure 14b In the modified scheme shown, the symbol extraction is the sampled signal.

[0105] In one possible implementation, such as Figure 15 As shown, the symbol processing module 7 can also be set between the sampling module 4 and the correlation calculation module 5. The symbol processing module 7 is used to convert the positive value of the sampled signal into a first fixed value, convert the negative value of the sampled signal into a second fixed value, and output the converted sampled signal to the correlation calculation module 5. Figure 15 The scheme shown is the same as Figure 14a Right now Figure 14b The proposed solutions are similar, the difference being that... Figure 14a and Figure 14bThe scheme shown includes a modulation and despreading module. Figure 15 The scheme shown does not include a modulation / despreading module.

[0106] The width of a chip in the modulation code can be greater than one sine wave period of the carrier wave; for example, one chip may correspond to 2, 3, 4, ... n sine wave periods of the carrier wave. In one possible implementation, the width of one chip in the modulation code is equal to one period of the carrier wave. (See reference...) Figure 9 High correlation occurs when signals with waveforms and phase angles are correlated. However, since a sine wave has multiple sampling points, the correlation gradually increases as data matching begins with the first sample of the last sine wave. The correlation reaches its maximum when all sampled data match, and then decreases again as the wave moves. Magnifying the time axis of the correlation peak reveals a triangle-like pattern, indicating a progression from low to high correlation, followed by a decline in correlation. Figure 16 As shown. Therefore, to accurately determine the timing of the correlation peak, the base of this triangle must be compressed as much as possible; the smaller the base, the more accurate the timing. In this case, setting the modulation code chip width to be equal to the period of a sine wave of one carrier wave can effectively reduce the base of this triangle. If a sine wave samples n points, the base of the triangle consists of 2*n clock lengths. The highest point of the correlation peak appears between the nth and (n+1)th clock cycles after the correlation peak appears, and the timing accuracy can be controlled within ±1 clock cycle.

[0107] In one possible implementation, during the sampling of the ultrasonic signal received by the second ultrasonic transducer, the sampling period is one-quarter of a sine wave period of the carrier wave.

[0108] Specifically, as mentioned above, due to the use of phase modulation, the sampling frequency does not need to be very high or modulation is unnecessary. A sine wave can be sampled at only four points. Taking 0° sampling as an example, the amplitudes of the four sampled points of a sine wave are 0V, 1V, 0V, and -1V. The amplitudes of the four sampled points of a phase-modulated sine wave are 0V, -1V, 0V, and 1V. Therefore, by using four sampling points, it is clear whether it is a sine wave with the initial phase or a sine wave with the phase modulated, that is, it is possible to determine whether a specified echo has appeared, without the judgment deviation problem caused by low sampling. In the existing technology, in order to prevent misjudgment, the sampling rate must be very high, thus requiring high-performance sampling hardware and consuming more hardware for subsequent correlation calculations. The solution of this application embodiment can greatly reduce the hardware circuit overhead.

[0109] In one possible implementation, such as Figure 1As shown, the ultrasonic sensor chip 10 may further include: a storage module 81, which is electrically connected to the correlation calculation module 5. The correlation calculation module 5 can calculate the correlation based on the reference signal stored in the storage module 81. In the embodiment where a modulation and despreading module 8 is provided, the storage module 81 stores information about the carrier and the modulation code. The modulation code is used to modulate and despread the received sampled signal, and the despread signal is then correlated with the carrier. Therefore, the modulation and despreading module 8 is electrically connected to the storage module 81 to read the modulation code and modulate and despread the sampled signal according to the modulation code. The correlation calculation module 5 is also electrically connected to the storage module 81 to read information related to the carrier (such as the carrier, or the carrier and sequence information orthogonal to the carrier) and perform correlation calculation. In embodiments where the modulation and despreading module 8 is not provided, the storage module 81 stores information related to the carrier and the modulation code. This information is the modulation wave, because the modulation wave is obtained by phase modulation of the carrier and the modulation code. Therefore, the modulation wave is also a type of information related to the carrier and the modulation code. The correlation calculation is performed between the modulation wave and the sampled signal. The correlation calculation module 5 is electrically connected to the storage module 9 to read information related to the modulation wave (such as the modulation wave, or the modulation wave and sequence information orthogonal to the modulation wave) and perform the correlation calculation.

[0110] In addition, in embodiments where a modulation / despreading module 8 is provided, the storage module 81 can be electrically connected to the carrier generation module 1 and the modulation code generation module 2 to store information corresponding to the carrier and modulation code. In embodiments where a modulation / despreading module 8 is not provided, the storage module 81 can be electrically connected to the phase modulation module 3 to store information corresponding to the modulated wave.

[0111] In addition, the sampling module 4 can be an analog-to-digital converter (ADC). Through the analog-to-digital conversion function of the ADC, the analog signal is sampled to generate a digital signal. That is, the analog signal of the second ultrasonic sensor is converted into a digital signal by the ADC for use by the subsequent modules.

[0112] This application also provides an ultrasonic signal processing method, which can be applied to the aforementioned ultrasonic sensor chip, such as... Figure 17 As shown, the signal processing method includes:

[0113] Step 101: Generate a carrier wave;

[0114] Step 102: Generate modulation code;

[0115] Step 103: Modulate the carrier wave according to the modulation code to obtain the modulated wave, and output it to the first ultrasonic transducer;

[0116] Step 104: Sample the ultrasonic signal received by the second ultrasonic transducer to obtain the sampled signal;

[0117] Step 105: Determine the correlation of the sampled signal based on the reference signal. The correlation is related to the modulation code and the carrier wave.

[0118] Step 106: Select the sampled signal whose correlation reaches the preset value as the specified echo.

[0119] The specific process and principle of this method are the same as those described in the above embodiments, and will not be repeated here.

[0120] In one possible implementation, such as Figure 18 As shown, before step 105, which determines the correlation of the sampled signal based on the reference signal, the method further includes: step 107, which modulates and despreads the sampled signal according to the modulation code; the reference signal is a carrier wave or a carrier-orthogonal wave orthogonal to the carrier wave.

[0121] In one possible implementation, such as Figure 19 As shown, in this process, there is no need to perform the modulation and despreading process, and the reference signal is the modulation wave or a modulation orthogonal wave orthogonal to the modulation wave.

[0122] In one possible implementation, such as Figure 20 , Figure 21 As shown in step 22, step 105, determining the correlation of the sampled signal based on the reference signal, includes: step 1051, calculating the first correlation between the timing of the sampled signal and the reference signal; step 1052, calculating the second correlation between the orthogonal timing of the sampled signal and the reference signal; step 106, determining the sampled signal whose correlation reaches a preset value as the designated echo, includes: determining the sampled signal whose sum of the first correlation and the second correlation reaches a preset value as the designated echo.

[0123] In one possible implementation, such as Figure 18 and Figure 20 As shown, the method further includes: before step 107, modulating and despreading the sampled signal according to the modulation code, performing step 108, converting the positive values ​​of the sampled signal to a first fixed value, and converting the negative values ​​of the sampled signal to a second fixed value; or, as shown... Figure 21 and Figure 22 As shown, before calculating the correlation, step 108 is performed to convert the positive values ​​of the sampled signal into a first fixed value and the negative values ​​of the sampled signal into a second fixed value.

[0124] In one possible implementation, such as Figures 19 to 22 As shown, before determining the correlation of the sampled signal based on the reference signal in step 105, the method further includes: step 108, converting the positive value of the sampled signal into a first fixed value and converting the negative value of the sampled signal into a second fixed value.

[0125] In one possible implementation, the modulation code includes a first code value and a second code value. During modulation, the first code value is used to flip the carrier phase by 180°, and the second code value is used to keep the carrier phase unchanged.

[0126] In one possible implementation, the chip width of the modulation code is equal to one period of the carrier wave.

[0127] In one possible implementation, during the sampling of the ultrasonic signal received by the second ultrasonic transducer, the sampling period is one-quarter of a sine wave period of the carrier wave.

[0128] In this application embodiment, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, the simultaneous existence of A and B, or the existence of B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, and c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0129] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An ultrasonic sensor chip, characterized in that, It includes a first receiving end, a second receiving end, a first transmitting end and a second transmitting end, as well as a driving circuit and a signal processing circuit; The first receiving end is used to receive a trigger signal and transmit the trigger signal to the driving circuit. The driving circuit outputs a modulated wave composed of several signals with opposite phases through the first transmitting end. The first transmitting end is used to couple to the ultrasonic transducer. The second receiving end is used to receive the ultrasonic signal transmitted from the ultrasonic transducer and transmit the ultrasonic signal to the signal processing circuit. The signal processing circuit performs correlation calculation on the ultrasonic signal according to the reference signal, and outputs a feedback signal indicating the occurrence of a specified echo when the correlation reaches a preset value. The feedback signal is output outward through the second transmitting end. The driving circuit includes a carrier generation module, a modulation code generation module, and a phase modulation module. The carrier generation module generates a carrier, and the modulation code generation module generates a modulation code. The phase modulation module modulates the phase of the carrier according to the modulation code. The modulation code includes a first code value and a second code value. During modulation, the first code value is used to flip the carrier phase by 180°, and the second code value is used to keep the carrier phase unchanged, thereby obtaining the modulated wave. The signal processing circuit includes a correlation calculation module, a processing module, and a sampling module. The correlation calculation module is used to determine the correlation of the ultrasonic signal based on the reference signal. The correlation is related to the modulation code and the carrier wave. The processing module is used to identify ultrasonic signals whose correlation reaches the preset value as designated echoes. The sampling module is used to sample the ultrasonic signal input from the second receiving end to obtain a sampled signal, and input the sampled signal to the correlation calculation module. The correlation calculation module determines the correlation between the sampled signal and the reference signal. The correlation calculation module is specifically used for: calculating a first correlation between the timing sequence corresponding to the sampled signal and the reference signal; calculating a second correlation between the orthogonal timing sequence corresponding to the sampled signal and the reference signal; determining the sampled signal whose sum of the first correlation and the second correlation reaches a preset value as a specified echo; and ensuring that the sum of the first correlation and the second correlation is not affected by the phase shift of the sampled signal. The preset value is related to time and decreases as time increases. The preset value is a correlation value. The correlation value is calculated by performing a convolution operation between a first operand and a second operand. The first operand is the sampled signal, and the second operand is the in-phase or quadrature signal component corresponding to the reference signal.

2. The ultrasonic sensor chip according to claim 1, characterized in that, The carrier generation module and the modulation code generation module are electrically connected to the first receiving end to receive the trigger signal.

3. The ultrasonic sensor chip according to claim 1, characterized in that, The ultrasonic sensor chip further includes a memory for storing the reference signal; the reference signal is the carrier wave or a carrier-orthogonal wave orthogonal to the carrier wave, or the reference signal is the modulation wave or a modulation-orthogonal wave orthogonal to the modulation wave.

4. The ultrasonic sensor chip according to claim 3, characterized in that, When the reference signal is the carrier wave or a carrier-orthogonal wave orthogonal to the carrier wave, the memory also stores information about the modulation code; the signal processing circuit further includes a modulation and despreading module, which is used to modulate and despread the sampled signal according to the information about the modulation code; The correlation calculation module performs correlation calculations on the reference signal and the sampled signal after modulation and despreading.

5. The ultrasonic sensor chip according to claim 1, characterized in that, Also includes: A symbol processing module is disposed between the sampling module and the correlation calculation module. The symbol processing module is used to convert the positive value of the sampled signal into a first fixed value and the negative value of the sampled signal into a second fixed value.

6. The ultrasonic sensor chip according to claim 1, characterized in that, The width of one chip of the modulation code is equal to one period of the carrier wave.

7. The ultrasonic sensor chip according to claim 1, characterized in that, During the sampling of the ultrasonic signal received by the ultrasonic transducer, the sampling period is one-quarter of a carrier cycle.

8. An ultrasonic radar device, characterized in that, include: The ultrasonic sensor chip as described in any one of claims 1 to 7 further includes an ultrasonic transducer; the ultrasonic transducer is electrically connected to the first transmitting end to receive the modulated wave and is used to transmit an ultrasonic signal according to the modulated wave; the ultrasonic transducer is also electrically connected to the second receiving end to transmit the received ultrasonic signal to the signal processing circuit.

9. The apparatus according to claim 8, characterized in that, Also includes: A microprocessor chip, the microprocessor chip including a third transmitter and a third receiver, the third transmitter being electrically connected to the first receiver to transmit the trigger signal, and the third receiver being electrically connected to the second transmitter to receive the feedback signal.

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