Laser radar

Abstract

The present disclosure provides a laser radar, comprising: a signal emission system configured to emit an optical signal; the signal receiving system is configured to receive the optical signal, convert the optical signal into an electric signal, convert the electric signal into a first differential signal and a second differential signal through a differential unit, and generate a digital signal corresponding to the optical signal according to the first differential signal and the second differential signal; the digital signal is used for representing information carried by the optical signal; wherein the differential unit adopts a symmetrical circuit structure. By adopting the technical scheme, the stability of digital signal generation in the optical communication receiving link can be improved, and the working performance of the laser radar is further improved.

Description

Technical Field

[0001] The present disclosure relates to the field of laser radar technology, and in particular to a laser radar. Background Art

[0002] With the rise of autonomous driving technology, LiDAR (Light Detection and Ranging) has received increasing attention as an important environmental perception component.

[0003] The working principle of lidar is: lidar emits detection light to the surrounding environment, and collects echo light reflected by external targets (such as vehicles, pedestrians, buildings, etc.) to obtain echo signals. After data processing based on the detection light signal and the echo signal, relevant information of the target can be obtained, such as the target's distance, direction, height, speed, posture, and even shape parameters, thereby realizing target detection.

[0004] Some laser radars use wireless optical communication technology to achieve data transmission between the upper and lower panels of the laser radar. Therefore, how to provide a technical solution to improve the stability of digital signal generation in the optical communication receiving link has become an urgent problem to be solved. Summary of the invention

[0005] In view of this, the present disclosure provides a laser radar, which can improve the stability of digital signal generation in an optical communication receiving link, thereby improving the working performance of the laser radar.

[0006] The laser radar provided by the present disclosure includes: a signal transmitting system configured to transmit an optical signal;

[0007] A signal receiving system is configured to receive the optical signal, convert the optical signal into an electrical signal, and convert the electrical signal into a first differential signal and a second differential signal through a differential unit, and generate a digital signal corresponding to the optical signal based on the first differential signal and the second differential signal, wherein the digital signal is used to characterize the information carried by the optical signal; wherein the differential unit adopts a symmetrical circuit structure.

[0008] Optionally, the signal receiving system comprises: a signal receiving unit configured to detect the optical signal and convert the optical signal into the electrical signal;

[0009] A differential unit, comprising a symmetrical first differential circuit and a second differential circuit; the differential unit is configured to convert the electrical signal into the first differential signal using the first differential circuit, and to convert the electrical signal into the second differential signal using the second differential circuit;

[0010] The digital signal generating unit is configured to generate a digital signal corresponding to the optical signal according to the first differential signal and the second differential signal.

[0011] Optionally, the first differential circuit includes a first differential conversion module, which is coupled to the signal receiving unit and the digital signal generating unit respectively, and is configured to amplify the electrical signal and convert the type of the electrical signal to obtain the first differential signal.

[0012] Optionally, the first differential conversion module includes: a first resistor and a second resistor, the first end of the first resistor is grounded, the second end of the first resistor is respectively coupled to the first end of the second resistor, the digital signal generating unit and the first end of the signal receiving unit; the second end of the second resistor is coupled to a power supply.

[0013] Optionally, the second differential circuit includes a second differential conversion module, which is coupled to the signal receiving unit and the digital signal generating unit respectively, and is configured to amplify the electrical signal and convert the type of the electrical signal to obtain the second differential signal.

[0014] Optionally, the second differential conversion module includes: a third resistor and a fourth resistor, the first end of the third resistor is coupled to the power supply, the second end of the third resistor is coupled to the first end of the fourth resistor, the digital signal generating unit and the second end of the signal receiving unit respectively; the second end of the fourth resistor is grounded.

[0015] Optionally, the amplification factor of the electrical signal amplified by the first differential conversion module and / or the second differential conversion module is adjustable.

[0016] Optionally, the signal receiving system further includes: a DC bias unit, coupled to the signal receiving unit and configured to provide a DC bias voltage to the signal receiving unit.

[0017] Optionally, the DC bias unit comprises: a bias voltage source, a first bias resistor and a second bias resistor, wherein:

[0018] The bias voltage source is coupled to a first end of the second bias resistor;

[0019] The second end of the second bias resistor is coupled to the second end of the signal receiving unit;

[0020] A first end of the first bias resistor is grounded, and a second end thereof is coupled to a first end of the signal receiving unit;

[0021] The voltage difference between the second end of the first bias resistor and the second end of the second bias resistor is used as the DC bias voltage.

[0022] Optionally, the signal receiving system further includes: a first filtering unit, coupled to the first end of the signal receiving unit and the first end of the first differential conversion module respectively, and configured to filter out noise of the electrical signal transmitted to the first differential conversion module;

[0023] The second filtering unit is coupled to the second end of the signal receiving unit and the first end of the second differential conversion module respectively, and is configured to filter out noise of the electrical signal transmitted to the second differential conversion module.

[0024] Optionally, the first filtering unit includes a first filter, a first end of the first filter is coupled to the first end of the signal receiving unit, and a second end of the first filter is coupled to the first end of the first differential conversion module;

[0025] The second filtering unit includes a second filter, a first end of the second filter is coupled to the second end of the signal receiving unit, and a second end of the second filter is coupled to the first end of the second differential conversion module.

[0026] Optionally, the first filtering unit includes a first capacitor, a first end of the first capacitor is respectively coupled to the first end of the signal receiving unit and the first end of the first differential conversion module, and a second end thereof is grounded;

[0027] The second filtering unit includes a second capacitor, a first end of the second capacitor is respectively coupled to the second end of the signal receiving unit and the first end of the second differential conversion module, and a second end of the second capacitor is grounded.

[0028] Optionally, the signal receiving system further comprises: a first DC isolation unit, coupled to the first end of the signal receiving unit and the first differential circuit respectively, and configured to isolate a DC component in the electrical signal transmitted to the first differential circuit;

[0029] The second DC isolation unit is coupled to the second end of the signal receiving unit and the second differential circuit respectively, and is configured to isolate the DC component of the electrical signal transmitted to the second differential circuit.

[0030] Optionally, the digital signal generating unit includes a comparison module, and the comparison module is configured to output a first digital signal when the voltage corresponding to the first differential signal is greater than the voltage corresponding to the second differential signal; and output a second digital signal when the voltage corresponding to the first differential signal is less than the voltage corresponding to the second differential signal.

[0031] Optionally, the signal receiving unit includes a photodetector.

[0032] Optionally, the signal receiving system further includes: a third filtering unit, disposed between the differential unit and the signal receiving unit, and configured to filter out noise in the electrical signal.

[0033] Optionally, the third filtering unit includes a common mode inductor.

[0034] Optionally, the laser radar also includes: a data processing system, coupled to the signal receiving system, and configured to process the digital signal to obtain information carried by the optical signal.

[0035] The laser radar provided by the present disclosure includes a signal transmitting system and a signal receiving system, wherein the signal receiving system can receive the optical signal transmitted by the signal transmitting system, and convert the optical signal into an electrical signal, and then the electrical signal can be converted into a first differential signal and a second differential signal through a differential unit. By converting the optical signal into an electrical signal and then further converting it into a differential signal for transmission, the use of differential signals for transmission can reduce interference and improve the signal-to-noise ratio, so that when a digital signal is generated according to the first differential signal and the second differential signal, the interference of the noise signal on the digital signal can be reduced, and the stability of the digital signal generation in the optical communication receiving link can be improved, thereby improving the working performance of the laser radar.

[0036] Furthermore, the signal receiving system includes a first differential circuit and a second differential circuit of symmetrical layout, so a simple circuit design can be used to implement the conversion of the electrical signal into a differential signal, thereby reducing the complexity and design cost of the circuit design. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments of the present disclosure or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 A schematic diagram of the structure of a laser radar in an embodiment of the present disclosure is shown;

[0039] Figure 2 A schematic diagram of the structure of a signal receiving system in an embodiment of the present disclosure is shown;

[0040] Figure 3 A specific structural schematic diagram of a signal receiving system in an embodiment of the present disclosure is shown;

[0041] Figure 4 A waveform diagram of corresponding monitoring points in a signal receiving system in an embodiment of the present disclosure is shown;

[0042] Figure 5 A schematic diagram showing the structure of another signal receiving system in an embodiment of the present disclosure is shown;

[0043] Figure 6 A specific structural schematic diagram of another signal receiving system in an embodiment of the present disclosure is shown;

[0044] Figure 7 A schematic diagram showing the change of the impedance characteristic of a first filter with the communication frequency in an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0045] As described in the background technology, when laser radar adopts wireless optical communication, the stability and reliability of optical signal transmission are low, which in turn reduces the stability of the digital signal generation process.

[0046] In order to solve the above technical problems, the embodiments of the present disclosure provide a laser radar, which can improve the stability of digital signal generation in an optical communication receiving link. Specifically, by converting an optical signal into an electrical signal and then further converting it into a differential signal for transmission, the use of differential signals for transmission can reduce interference and improve the signal-to-noise ratio, so that when a digital signal is generated according to the first differential signal and the second differential signal, the interference of the noise signal on the digital signal can be reduced, the stability of digital signal generation in the optical communication receiving link can be improved, and the working performance of the laser radar can be improved.

[0047] In order to enable those skilled in the art to better understand and implement the embodiments of the present disclosure, the concepts, schemes, principles and advantages of the embodiments of the present disclosure are described in detail below with reference to the accompanying drawings and through specific application examples.

[0048] The present disclosure provides a laser radar, such as Figure 1 The structure diagram of a laser radar is shown in FIG. 1 . In some embodiments, the laser radar 100 may include: a signal transmitting system 110 and a signal receiving system 120, wherein:

[0049] A signal transmitting system 110 configured to transmit an optical signal;

[0050] The signal receiving system 120 is configured to receive the optical signal, convert the optical signal into an electrical signal, and transmit the optical signal to the optical signal through a differential unit (eg Figure 2 The differential unit 122 in the optical signal converter converts the electrical signal into a first differential signal and a second differential signal, and generates a digital signal corresponding to the optical signal according to the first differential signal and the second differential signal, wherein the digital signal is used to characterize the information carried by the optical signal; wherein the differential unit adopts a symmetrical circuit structure.

[0051] In a specific implementation, the signal receiving system 120 can receive an optical signal from the signal transmitting system 110, and convert the type of the optical signal to obtain a corresponding electrical signal, and then use a differential unit with a symmetrical circuit structure to convert the electrical signal into a first differential signal and a second differential signal, so that the first differential signal and the second differential signal can be transmitted in the form of differential signals. This transmission method can reduce interference, and the electrical signal is converted into a differential signal. Since the differential signal itself has a strong anti-interference characteristic, it can also reduce interference and improve the signal-to-noise ratio. When a digital signal is generated according to the first differential signal and the second differential signal, the interference of the noise signal on the digital signal can be reduced, and the stability of the digital signal generation in the optical communication receiving link can be improved, thereby improving the working performance of the lidar.

[0052] Among them, the differential signal refers to a signal with the same amplitude and opposite phase generated on two branches in the optical communication receiving link. Therefore, in the embodiment of the present disclosure, a differential unit with a symmetrical circuit structure is adopted to convert the electrical signal to obtain two signals that are differential signals of each other, namely, a first differential signal and a second differential signal.

[0053] In order to enable those skilled in the art to better understand and implement the embodiments of the present disclosure, some specific examples are given below for the specific implementation methods of the laser radar in the embodiments of the present disclosure.

[0054] In some embodiments of the present disclosure, the signal transmitting system may be any device or equipment capable of transmitting an optical signal.

[0055] As an optional example, the signal transmission system may include a light source, which can transmit information by emitting a light signal with varying brightness.

[0056] In some embodiments, the light source may be implemented by a light emitting diode LED or a laser diode LD.

[0057] As an optional example, the light source may include one LED or one LD, or may include multiple LEDs or multiple LDs, and the multiple LEDs or multiple LDs may be configured according to a preset connection relationship.

[0058] It should be noted that the present disclosure does not limit the specific type of light source, as long as it can emit light signals when applied to a laser radar.

[0059] In a specific implementation, the signal receiving system can convert the received optical signal into a corresponding digital signal. For example, the signal receiving system can transmit information according to the optical signal with varying brightness emitted by the light source to obtain a digital signal corresponding to the optical signal.

[0060] In some embodiments of the present disclosure, reference Figure 2 The structure diagram of a signal receiving system shown in FIG. 1 is a schematic diagram of a signal receiving system, wherein the signal receiving system 120 may include: a signal receiving unit 121, a differential unit 122 and a digital signal generating unit 123, wherein:

[0061] The signal receiving unit 121 is configured to detect the optical signal and convert the optical signal into the electrical signal;

[0062] The differential unit 122 includes a symmetrical first differential circuit ( Figure 2 not shown) and a second differential circuit ( Figure 2 The differential unit 122 is configured to convert the electrical signal into the first differential signal using the first differential circuit, and to convert the electrical signal into the second differential signal using the second differential circuit;

[0063] The digital signal generating unit 123 is configured to generate a digital signal corresponding to the optical signal according to the first differential signal and the second differential signal.

[0064] In an optional implementation, combined with Figure 1 and Figure 2 The signal receiving unit 121 can detect the light signal of the brightness change emitted by the signal transmitting system 110 in real time. When the light signal is detected, the signal receiving unit 121 can convert the detected light signal into an electrical signal. The differential unit 122 can use a first differential circuit to convert the electrical signal into the first differential signal, and use a second differential circuit to convert the electrical signal into the second differential signal. Then, the digital signal generating unit 123 can generate a digital signal corresponding to the light signal according to the first differential signal and the second differential signal. Since the digital signal can be used to characterize the brightness change of the light signal, the information carried by the light signal can be obtained by processing the digital signal, such as the control signal for controlling the scanning module to perform detection and the point cloud data detected by the laser radar.

[0065] By using the first differential circuit and the second differential circuit with a symmetrical layout, the same electrical signal can be synchronously converted and amplified, and the first differential signal and the second differential signal, which are differential signals of each other, can be independently obtained, which can ensure the synchronization of differential signal generation and reduce the probability of crosstalk between the first differential signal and the second differential signal, thereby reducing interference. Therefore, when the digital signal generation unit generates the digital signal corresponding to the optical signal according to the first differential signal and the second differential signal, the influence of the noise signal on the digital signal can be reduced, and the stability of digital signal generation can be further improved.

[0066] In an optional implementation, the signal receiving unit may include a photoelectric detector (PD), which can convert an optical signal into an electrical signal.

[0067] In some other embodiments, the signal receiving unit may also include other devices capable of detecting optical signals, such as a photoelectric measurement sensor and an avalanche photodiode. The embodiments of the present disclosure do not impose any limitation on the type of the signal receiving unit.

[0068] In a specific implementation, after the optical signal is converted into an electrical signal, different differential conversion modules in the differential unit may be used to perform differential processing on the electrical signal to obtain a first differential signal and a second differential signal.

[0069] As an alternative example, continue to refer to Figure 2 The first differential circuit may include a first differential conversion module 1221, which may be coupled to the signal receiving unit 121 and the digital signal generating unit 123 respectively, and configured to amplify the electrical signal and convert the type of the electrical signal to obtain the first differential signal.

[0070] Specifically, when the signal receiving unit 121 converts the optical signal into an electrical signal, the electrical signal will be transmitted to the first differential conversion module 1221, and then the first differential conversion module 1221 can amplify and type convert the electrical signal, thereby increasing the gain of the obtained first differential signal, and the signal type can be adapted to the digital signal generating unit, so as to obtain a digital signal corresponding to the optical signal.

[0071] Accordingly, continue to refer to Figure 2 The second differential circuit may include a second differential conversion module 1222, which may be coupled to the signal receiving unit 121 and the digital signal generating unit 123 respectively, and configured to amplify the electrical signal and convert the type of the electrical signal to obtain the second differential signal.

[0072] Specifically, when the signal receiving unit 121 converts the optical signal into an electrical signal, the electrical signal will be transmitted to the second differential conversion module 1222, and then the second differential conversion module 1222 can amplify and type convert the electrical signal, thereby increasing the gain of the obtained second differential signal, and the signal type can be adapted to the digital signal generating unit, so as to obtain a digital signal corresponding to the optical signal.

[0073] In a specific implementation, differential conversion modules with different structures and characteristics may be used to perform differential conversion processing on the electrical signal to obtain the corresponding first differential signal and second differential signal.

[0074] As an optional example, combining Figure 2 , and refer to Figure 3 A specific structural diagram of a signal receiving system in an embodiment of the present disclosure is shown in FIG. Figure 3 As shown, the first differential conversion module 1221 may include: a first resistor R1 and a second resistor R2, the first end of the first resistor R1 is grounded, the second end of the first resistor R1 is coupled to the first end of the second resistor R2, the digital signal generating unit 123 and the first end of the signal receiving unit 121, respectively; the second end of the second resistor R2 is coupled to the power supply VDD.

[0075] Specifically, when the signal receiving unit 121 converts the optical signal into an electrical signal, the electrical signal can flow to the first resistor R1. At this time, the first resistor R1 can simultaneously amplify and perform type conversion processing on the electrical signal to obtain a corresponding first differential signal.

[0076] As an example, if the electrical signal is a current signal, when passing through the first resistor R1, the current signal can be converted into a voltage signal (which can also be considered as a first differential signal), and by making the first resistor R1 have a larger resistance value, the amplitude of the converted voltage signal can be increased, that is, it plays a role in amplifying and converting the type of the current signal.

[0077] Next refer to Figure 3 Since the first end of the first resistor R1 can be grounded, and the second end thereof can be coupled to the digital signal generating unit 123 and the first end of the second resistor R2 respectively, and the second end of the second resistor R2 can be coupled to the power supply VDD, the voltage value provided by the power supply VDD can be divided by the first resistor R1 and the second resistor R2, and the divided voltage value corresponding to the first resistor R1 is used as the static working voltage of one end of the digital signal generating unit 123.

[0078] As an example, one end of the digital signal generating unit (eg Figure 3 The static operating voltage U of the first input terminal of the comparator CMP is shown in FIG. s1 Can be:

[0079]

[0080] Among them, U VDD Represents the voltage value provided by the power supply VDD; R R1 represents the resistance value of the first resistor R1; R R2 Indicates the resistance value of the second resistor R2.

[0081] Therefore, by adopting the first resistor and the second resistor having the above-mentioned connection relationship, the electrical signal from the signal receiving unit can be amplified and type converted to obtain a first differential signal, and the voltage value provided by the power supply can be divided, thereby providing a static operating voltage for one end of the digital signal generating unit.

[0082] As an alternative example, continue to refer to Figure 3 The second differential conversion module 1222 may include a third resistor R3 and a fourth resistor R4, the first end of the third resistor R3 may be coupled to the power supply VDD, the second end of the third resistor R3 may be coupled to the first end of the fourth resistor R4, the digital signal generating unit 123 and the second end of the signal receiving unit 121 respectively; the second end of the fourth resistor R4 may be grounded.

[0083] Specifically, when the signal receiving unit 121 converts the optical signal into an electrical signal, the electrical signal can flow to the fourth resistor R4. At this time, the fourth resistor R4 can simultaneously amplify and perform type conversion processing on the electrical signal to obtain a corresponding second differential signal.

[0084] As an example, if the electrical signal is a current signal, the current signal can be converted into a voltage signal (which can also be considered as a second differential signal) when passing through the fourth resistor R4, and by making the fourth resistor R4 have a larger resistance value, the amplitude of the converted voltage signal can be increased, that is, it plays a role in amplifying and converting the type of the current signal.

[0085] Next refer to Figure 3 Since the first end of the third resistor R3 is connected to the power supply VDD, the second end thereof can be coupled to the digital signal generating unit 123 and the first end of the fourth resistor R4 respectively, and the second end of the fourth resistor R4 can be grounded, the voltage value provided by the power supply VDD can be divided by the third resistor R3 and the fourth resistor R4, and the divided voltage value corresponding to the fourth resistor R4 is used as the static working voltage of one end of the digital signal generating unit 123.

[0086] As an example, one end of the digital signal generating unit (eg Figure 3 The static operating voltage U of the second input terminal of the comparator CMP is shown in FIG. s2 Can be:

[0087]

[0088] It can be seen from the above formulas (1) and (2) that, through the first differential conversion module and the second differential conversion module, a static operating voltage can be provided to both ends of the digital signal generating unit, ensuring that the voltage amplitude corresponding to the signal at the input end of the digital signal generating unit can stably cross the threshold, so that the digital signal generating unit can work normally under the action of the static operating voltage.

[0089] To facilitate understanding of the process of processing the electrical signal to obtain the first differential signal and the second differential signal in the embodiment of the present disclosure, a detailed description is given below with reference to the accompanying drawings.

[0090] Combination Figure 3 , refer to Figure 4 The waveform diagram of the corresponding monitoring points in a signal receiving system in an embodiment of the present disclosure is shown, wherein: Figure 4 The waveform diagram of the current signal I converted by the signal receiving unit within 0 to 50 μs, the waveform diagram of the first differential signal U1 converted by the first differential conversion module, and the waveform diagram of the second differential signal U2 converted by the second differential conversion module are shown.

[0091] like Figure 4 As shown, in the time period from t1 to t3, a schematic diagram of the waveform change of the current signal I in a period of time is shown, and the current signal I may include a high level segment and a low level segment, wherein:

[0092] During the period from t1 to t2, the current signal I is in a low level segment, and its corresponding signal amplitude is I2 (unit can be μA). When the current signal I with a signal amplitude of I2 is converted into a first differential signal by the first differential conversion module, a voltage value U corresponding to the first differential signal can be obtained. 12 (unit can be V); when the current signal I with a signal amplitude of I2 is converted into a second differential signal by the second differential conversion module, the voltage value U corresponding to the second differential signal can be obtained. 21 (The unit can be V).

[0093] At time t2, the current signal I changes from a low level to a high level.

[0094] During the period from t2 to t3, the current signal I is in the high level segment, and its corresponding signal amplitude is I1. When the current signal I with the signal amplitude I1 is converted into the first differential signal by the first differential conversion module, the voltage U corresponding to the first differential signal can be obtained. 11 When the current signal I with a current amplitude of I1 is converted into a second differential signal by the second differential conversion module, a voltage U corresponding to the second differential signal can be obtained. 22 .

[0095] Among them, since the first differential signal and the second differential signal are differential signals, the voltage corresponding to the first differential signal and the voltage corresponding to the second differential signal have equal amplitudes and a phase difference of 180°, it can be considered that the voltage corresponding to the first differential signal and the voltage corresponding to the second differential signal are differential voltages.

[0096] Next refer to Figure 4 , whether in the period from t1 to t2 or the period from t2 to t3, the first differential voltage corresponding to the first differential signal and the second differential voltage corresponding to the second differential signal are different. When the first differential signal and the second differential signal are input to the digital signal generating unit, a differential mode voltage can be generated at the input end of the digital signal generating unit. For example, the differential mode voltage can be: U 21 -U 12 Or: U 11 -U 22 , and then under the action of the differential mode voltage, the digital signal generating unit can generate a corresponding digital signal.

[0097] It should be noted that, first of all, Figure 4 It is only used to illustrate that the electrical signal can be converted into the first differential signal and the second differential signal through the first differential conversion module and the second differential conversion module. Figure 4 The current signal, the voltage signal corresponding to the first differential signal, and the voltage signal corresponding to the second differential signal, the amplitude, pulse width, pulse number, and high and low level transition moments shown in the figure are only examples. Different waveform diagrams can be obtained for different optical communication receiving scenarios, and the present disclosure does not limit this. Secondly, Figure 4 The description is made by taking the electrical signal as a current signal as an example. In some other embodiments, the electrical signal may also be a voltage signal.

[0098] In a specific implementation, when a differential unit is used to convert an electrical signal into a first differential signal and a second differential signal, a first differential signal and / or a second differential signal with different amplification ratios can be obtained according to actual needs.

[0099] As an implementation example, the amplification factor of the electrical signal amplified by the first differential conversion module and / or the second differential conversion module in the embodiment of the present disclosure is adjustable.

[0100] That is, by adjusting the differential amplification ratio of the first differential conversion module and / or the second differential conversion module, the amplification factor of the electrical signal can be controlled, and the electrical signal can be amplified to different degrees, thereby obtaining a first differential signal and / or a second differential signal with different amplitudes, so that the signal receiving system can be suitable for different scenarios.

[0101] For example, when the electrical signal strength is weak, the signal strengths of the first differential signal and the second differential signal obtained by converting the electrical signal are low. At this time, the signal strengths of the first differential signal and the second differential signal output to the digital signal generating unit may not be able to stably cross the threshold, and the signal-to-noise ratio of the signal receiving system will be reduced, affecting the stability of the digital signal generation.

[0102] In some embodiments, the resistance values ​​of the first resistor, the second resistor, the third resistor, and the fourth resistor can be adjusted to amplify the electrical signal to different degrees.

[0103] The resistance value of the resistor can be adjusted in the following ways: 1) switching resistors with different resistance values ​​as the first resistor, the second resistor, the third resistor and the fourth resistor; 2) the first resistor, the second resistor, the third resistor and the fourth resistor themselves are variable resistors, for example, their own resistance value can be changed by changing the length connected to the circuit; for example, changing the external light intensity or temperature to change their own resistance value.

[0104] In some embodiments, by adjusting the resistance values ​​of the first resistor, the second resistor, the third resistor, and the fourth resistor, the bandwidth and the communication frequency of the generated digital signal can be changed.

[0105] As a specific implementation example, the bandwidth of the digital signal may be 10 Mbps to 50 Mbps, and the communication frequency of the signal receiving system may be 1 MHz to 5 MHz.

[0106] It can be understood that the method of adjusting the resistance value of the resistor described in the above example is only an example. In actual work, it can be selected according to needs. The embodiment of the present disclosure does not impose any limitation on the method of adjusting the resistance value of the resistor.

[0107] In other embodiments, the signal receiving system includes multiple first differential conversion modules and / or second differential conversion modules with different amplification factors, and different degrees of amplification of the electrical signal are achieved by connecting different first differential conversion modules and / or second differential conversion modules to the circuit.

[0108] In some embodiments of the present disclosure, the first differential conversion module and / or the second differential conversion module having an amplification factor can be connected between the signal receiving unit and the digital signal generating unit in a variety of ways.

[0109] As an optional example, the differential unit in the embodiment of the present disclosure may also include multiple first selection channels and multiple second selection channels, one first selection channel corresponds to a first differential conversion module, and the first selection channel is coupled between the corresponding first differential conversion module and the signal receiving unit, one second selection channel corresponds to a second differential conversion module, and the second selection channel is coupled between the corresponding second differential conversion module and the signal receiving unit; the first selection channel is configured to, when being selected, conduct the path between the corresponding first differential conversion module and the signal receiving unit; the second selection channel is configured to, when being selected, conduct the path between the corresponding second differential conversion module and the signal receiving unit; wherein, the amplification factor of the first differential conversion module and the second differential conversion module in the conducting state is the current differential conversion ratio of the differential unit to the electrical signal.

[0110] In a specific implementation, in order to make the first differential conversion module and the second differential conversion module have the same amplification factor, the resistance values ​​of the first resistor and the third resistor may be the same, and the resistance values ​​of the second resistor and the fourth resistor may be the same.

[0111] By using the differential unit in the above example, the electrical signal can be converted into a first differential signal and a second differential signal, and the amplification factor of the electrical signal amplified by the first differential conversion module and / or the second differential conversion module can be adjusted, so that the first differential signal and the second differential signal with different amplitudes can be obtained, and then the digital signal generation unit can generate a corresponding digital signal based on the first differential signal and the second differential signal.

[0112] In some embodiments of the present disclosure, Figure 3 As shown, the digital signal generating unit 123 may include a comparison module CMP, and the comparison module CMP is configured to output a first digital signal when the voltage corresponding to the first differential signal is greater than the voltage corresponding to the second differential signal; and output a second digital signal when the voltage corresponding to the first differential signal is less than the voltage corresponding to the second differential signal.

[0113] As a specific example, continue to refer to Figure 4 , and also shows the digital signal U generated by the digital signal generating unit within 0 to 50 μs o Waveform diagram of .

[0114] During the period from t1 to t2, the voltage value U corresponding to the first differential signal 12 Less than the voltage value U corresponding to the second differential signal 21 , the comparison module can output a signal amplitude of U o1 The first digital signal; in the period from t2 to t3, the voltage value U corresponding to the first differential signal 11 Greater than the voltage U corresponding to the second differential signal22 , the comparison module can output a signal amplitude of U o2 The second digital signal.

[0115] It should be noted that Figure 4 The amplitude, pulse width, number of pulses, and transition moments of the high and low levels of the illustrated digital signal are only examples. Different waveform diagrams may be obtained for different optical communication receiving scenarios, and the embodiments of the present disclosure do not impose any restrictions on this.

[0116] In some embodiments of the present disclosure, the comparison module may include a comparator, wherein a first input terminal of the comparator may be connected to the first differential conversion module, and a second input terminal of the comparator may be connected to the second differential conversion module.

[0117] In a specific implementation, in order to further improve the stability of digital signal generation, the structure of the laser radar in the embodiment of the present disclosure may be further expanded.

[0118] In a specific implementation, according to actual application scenarios and requirements, the laser radar in the embodiment of the present disclosure can be further expanded to further improve the stability of digital signal generation.

[0119] As an alternative example, refer to Figure 5 As shown in the structural schematic diagram of another signal receiving system in the embodiment of the present disclosure, the signal receiving system 120 in the embodiment of the present disclosure may also include: a DC bias unit 124, which can be coupled to the signal receiving unit 121 and configured to provide a DC bias voltage to the signal receiving unit 121.

[0120] In an optional implementation, the DC bias unit 124 can provide a DC source electrical signal to the signal receiving unit 121, so that the signal receiving unit 121 can detect the optical pulse signal emitted by the signal transmitting system (such as a light source) and convert the optical pulse signal into a voltage signal.

[0121] In some embodiments of the present disclosure, Figure 6 As shown in the specific structural diagram of another signal receiving system in the embodiment of the present disclosure, the DC bias unit 124 may include a bias voltage source VCC and a first bias resistor R5 and a second bias resistor R6, wherein:

[0122] The bias voltage source VCC is coupled to the first end of the second bias resistor R6, the second end of the second bias resistor R6 is coupled to the second end of the signal receiving unit 121, the first end of the first bias resistor R5 is grounded, and the second end of the first bias resistor R5 is coupled to the first end of the signal receiving unit 121.

[0123] The voltage difference between the second end of the first bias resistor R5 and the second end of the second bias resistor R6 serves as the DC bias voltage.

[0124] That is, the DC bias unit in the above example can provide a stable DC bias voltage for the signal receiving unit, thereby further improving the stability of digital signal generation.

[0125] As another alternative example, Figure 6 As shown, the signal receiving system 120 may further include a first filtering unit 125 and a second filtering unit 126, wherein:

[0126] The first filtering unit 125 may be coupled to the first end of the signal receiving unit 121 and the first end of the first differential conversion module 1221, respectively, and configured to filter out noise of the electrical signal transmitted to the first differential conversion module 1221;

[0127] The second filtering unit 126 may be coupled to the second end of the signal receiving unit 121 and the first end of the second differential conversion module 1222 , respectively, and configured to filter out noise of the electrical signal transmitted to the second differential conversion module 1222 .

[0128] Therefore, by providing the first filtering unit and the second filtering unit that can filter out the noise of the electrical signal, the quality of the electrical signal output to the first differential conversion module and the second differential conversion module can be improved, thereby reducing the influence of noise on the generated first differential signal and the second differential signal, and improving the signal-to-noise ratio.

[0129] In some embodiments of the present disclosure, Figure 7 As shown, the first filtering unit 125 may include a first filter F1 , a first end of the first filter F1 may be coupled to a first end of the signal receiving unit 121 , and a second end thereof may be coupled to a first end of the first differential conversion module 1221 .

[0130] The second filtering unit 126 may include a second filter F2 , a first end of the second filter F2 is coupled to the second end of the signal receiving unit 121 , and a second end of the second filter F2 is coupled to the first end of the second differential conversion module 1222 .

[0131] In some other embodiments of the present disclosure, the first filtering unit 125 may include a first capacitor C1, a first end of the first capacitor C1 is respectively coupled to the first end of the signal receiving unit 121 and the first end of the first differential conversion module 1221, and a second end thereof is grounded.

[0132] The second filtering unit 126 may include a second capacitor C2, a first end of the second capacitor C2 is respectively coupled to the second end of the signal receiving unit 121 and the first end of the second differential conversion module 1222, and a second end thereof is grounded.

[0133] In some embodiments, to further improve the denoising effect, continue to refer to Figure 7 The first filtering unit 125 may include a first filter F1 and a first capacitor C1, and the second end of the first filter F1 may be connected to the first end of the first capacitor C1. That is, the first filter F1 and the first capacitor C1 together constitute a first low-pass filter to absorb differential mode noise interference and reduce interference.

[0134] The second filtering unit 126 may include a second filter F2 and a second capacitor C2, and the second end of the second filter F2 may be connected to the first end of the second capacitor C2. That is, the second filter F2 and the second capacitor C2 together constitute a second low-pass filter to absorb differential mode noise interference and reduce interference.

[0135] In some specific implementation examples, the first filter and the second filter may have the same impedance characteristics. As a specific example, refer to Figure 7 The schematic diagram of the impedance characteristic of a first filter according to the embodiment of the present disclosure as it changes with the communication frequency is shown, wherein the horizontal axis represents the communication frequency and the vertical axis represents the impedance value of the first filter. Figure 7 As shown, the variation curve of the impedance Z of the first filter, the variation curve of the resistance R of the first filter, and the variation curve of the inductance X of the first filter are respectively shown. Figure 7 It can be seen that as the communication frequency increases, the inductance value X, the resistance value R and the impedance value Z of the first filter all increase, thereby being able to filter out high-frequency noise.

[0136] In some optional examples of the present disclosure, the first filter and the second filter may be ferrite beads.

[0137] It should be noted that the first filtering unit and the second filtering unit may also be other components that can filter out noise. For example, the first filtering unit and the second filtering unit may include a device composed of at least two elements of a capacitor, a resistor or an inductor. The embodiments of the present disclosure do not impose any restrictions on this.

[0138] As another optional example, Figure 5 As shown, the signal receiving system 120 may further include: a first DC isolation unit 127 and a second DC isolation unit 128, wherein:

[0139] The first DC isolation unit 127 may be coupled to the first end of the signal receiving unit 121 and the first differential conversion module respectively, and is configured to isolate a DC component in the electrical signal transmitted to the first differential circuit.

[0140] The second DC isolation unit 128 may be coupled to the second end of the signal receiving unit 121 and the first differential conversion module respectively, and is configured to isolate a DC component in the electrical signal transmitted to the second differential circuit.

[0141] Therefore, by providing the first DC isolation unit and the second DC isolation unit capable of isolating the DC component in the electrical signal, the influence of the DC component in the electrical signal on the generated first differential signal and the second differential signal can be reduced.

[0142] In some embodiments of the present disclosure, Figure 6 As shown, the first DC blocking unit 127 may include a first DC blocking capacitor C3, and the second DC blocking unit 128 may include a second DC blocking capacitor C4.

[0143] In an optional example, the capacitance values ​​of the first DC blocking capacitor C3 and the second DC blocking capacitor C4 may be the same.

[0144] As another optional example, Figure 5 As shown, the signal receiving system 120 in the embodiment of the present disclosure may further include a third filtering unit 129, which may be disposed between the differential unit 122 and the signal receiving unit 121 and configured to filter out noise in the first differential signal and the second differential signal.

[0145] By filtering out the noise in the electrical signal, the impact of interference on the digital signal can be reduced, further improving the stability of digital signal generation.

[0146] In some embodiments of the present disclosure, Figure 6 As shown, the third filtering unit 129 may include a common-mode inductor, wherein the common-mode inductor may include: a first common-mode coil L1 and a second common-mode coil L2, wherein the first end of the first common-mode coil L1 and the first end of the second common-mode coil L2 are both coupled to the signal receiving unit 121, and the second end of the first common-mode coil L1 and the second end of the second common-mode coil L2 are both coupled to the differential unit 122.

[0147] In addition, the common-mode inductor is used as the third filtering unit, which can reduce the electromagnetic interference (EMI) signal generated by the line itself in the signal receiving system when it is working and suppress common-mode noise, which can effectively reduce the EMI interference intensity and improve the communication quality.

[0148] It should be noted that the above describes multiple embodiment schemes provided by the embodiments of the present disclosure. The various optional methods introduced in each embodiment scheme can be combined and cross-referenced with each other without conflict, thereby extending a variety of possible embodiment schemes, which can all be considered as embodiment schemes disclosed and disclosed by the present disclosure.

[0149] In order to better understand and implement the specific working principle of the signal receiving system provided by the embodiment of the present disclosure, the following is described in detail through specific examples in conjunction with the accompanying drawings.

[0150] Reference Figure 6 The structure diagram of the signal receiving system in a specific application scenario in the embodiment of the present disclosure is shown, wherein the specific structure of each unit in the signal receiving system can refer to the above example, and will not be described here. The connection relationship within the signal receiving system is as follows:

[0151] The first end of the second bias voltage R6 can be connected to the bias voltage source VCC, and the second end of the second bias voltage R6 can be connected to the second end of the photodetector PD and the first end of the second filter F2 respectively; the first end of the first bias voltage R5 can be grounded, and the second end of the first bias voltage R5 can be connected to the first end of the photodetector PD and the first end of the first filter F1 respectively.

[0152] The second end of the first filter F1 can be connected to the first end of the first capacitor C1 and the first end of the first DC blocking capacitor C3 respectively, and the second end of the first capacitor C1 can be grounded; the second end of the second filter F2 can be connected to the first end of the second capacitor C2 and the first end of the second DC blocking capacitor C4 respectively, and the second end of the second capacitor C2 can be grounded.

[0153] The second end of the first DC blocking capacitor C3 may be connected to the first end of the first common mode coil L1 , and the second end of the second DC blocking capacitor C4 may be connected to the first end of the second common mode coil L2 .

[0154] The second end of the first common mode coil L1 can be connected to the second end of the first resistor R1, the first end of the second resistor R2, and the first input end (i.e., the inverting input end) of the comparator CMP respectively; the first end of the first resistor R1 can be grounded; the second end of the second resistor R2 can be connected to the power supply VDD.

[0155] The second end of the second common mode coil L2 can be connected to the second end of the third resistor R3, the first end of the fourth resistor R4, and the second input end (i.e., the in-phase input end) of the comparator CMP respectively; the first end of the third resistor R3 can be connected to the power supply VDD; the second end of the fourth resistor R4 can be grounded.

[0156] The working principle of the signal receiving system is:

[0157] The DC source VCC, the first bias voltage R5 and the second bias voltage R6 provide a stable DC bias voltage for the photodetector PD, and the photodetector PD can convert the detected light signal into an electrical signal; the first low-pass filter composed of the first filter F1 and the first capacitor C1 can filter out the high-frequency noise of the electrical signal flowing to the first common-mode coil L1, and the second low-pass filter composed of the second filter F2 and the second capacitor C2 can filter out the high-frequency noise of the electrical signal flowing to the second common-mode coil L2; the first DC blocking capacitor C3 can isolate the DC component in the electrical signal transmitted to the first common-mode coil L1, and the second DC blocking capacitor C4 can isolate the DC component in the electrical signal transmitted to the second common-mode coil L2.

[0158] Since the differential unit in the embodiment of the present disclosure is a symmetrical circuit structure, the use of the first common mode coil L1 and the second common mode coil L2 in common mode can eliminate common mode interference and reduce interference to the electrical signal output to the first resistor R1 and the fourth resistor R4.

[0159] Through the first resistor R1 and the fourth resistor R4, the electrical signal can be amplified and type-converted to obtain a first differential signal and a second differential signal with the same amplitude and a phase difference of 180°, and the first differential signal is output to the first input terminal of the comparator CMP, and the second differential signal is output to the second input terminal of the comparator CMP, so that the comparator CMP can generate a corresponding digital signal according to the first differential signal and the second differential signal to complete the receiving process of the optical communication signal.

[0160] It is understandable that the above Figure 6 The structure shown is only an example. In a specific implementation, the above circuit can be modified or selected. For example, the photodetector PD can be replaced by an avalanche photodiode, etc.; for another example, the third filter unit can be omitted. Based on this, different extension schemes can be obtained, and the embodiments of the present disclosure do not limit these extension schemes.

[0161] In some embodiments of the present disclosure, the laser radar may further include a data processing system, which may be coupled to the signal receiving system and configured to process the digital signal to obtain information carried in the optical signal.

[0162] For example, by processing digital signals, control signals, point cloud data, etc. can be obtained.

[0163] In some embodiments, the data processing system can be implemented by a processing chip such as a central processing unit (CPU), a field programmable gate array (FPGA), or an application specific integrated circuit (ASIC) or one or more integrated circuits configured to implement the embodiments of the present disclosure.

[0164] It should be noted that the "one embodiment" or "embodiment" referred to in the present invention refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. And in the description of the present invention, the terms "first", "second", "third", "fourth" and the like are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined by the terms "first", "second", "third", "fourth" and the like may explicitly or implicitly include one or more of the features. Moreover, the terms "first", "second", "third", "fourth" and the like are used to distinguish similar objects, and are not necessarily used to describe a specific order or to express importance. It is understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present disclosure described herein can be implemented in an order other than that illustrated or described.

[0165] Although the embodiments of the present disclosure are disclosed as above, the present invention is not limited thereto. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A laser radar, characterized in that: include: a signal transmitting system configured to transmit an optical signal; A signal receiving system is configured to receive the optical signal, convert the optical signal into an electrical signal, and convert the electrical signal into a first differential signal and a second differential signal through a differential unit, and generate a digital signal corresponding to the optical signal based on the first differential signal and the second differential signal, wherein the digital signal is used to characterize the information carried by the optical signal; wherein the differential unit adopts a symmetrical circuit structure.

2. The laser radar according to claim 1, characterized in that: The signal receiving system comprises: a signal receiving unit, configured to detect the optical signal and convert the optical signal into the electrical signal; A differential unit, comprising a symmetrical first differential circuit and a second differential circuit; the differential unit is configured to convert the electrical signal into the first differential signal using the first differential circuit, and to convert the electrical signal into the second differential signal using the second differential circuit; The digital signal generating unit is configured to generate a digital signal corresponding to the optical signal according to the first differential signal and the second differential signal.

3. The laser radar according to claim 2, characterized in that: The first differential circuit includes a first differential conversion module, which is coupled to the signal receiving unit and the digital signal generating unit respectively, and is configured to amplify the electrical signal and convert the type of the electrical signal to obtain the first differential signal.

4. The laser radar according to claim 3, characterized in that: The first differential conversion module includes: a first resistor and a second resistor, the first end of the first resistor is grounded, the second end of the first resistor is coupled to the first end of the second resistor, the digital signal generating unit and the first end of the signal receiving unit respectively; the second end of the second resistor is coupled to a power supply.

5. The laser radar according to claim 3, characterized in that: The second differential circuit includes a second differential conversion module, which is coupled to the signal receiving unit and the digital signal generating unit respectively, and is configured to amplify the electrical signal and convert the type of the electrical signal to obtain the second differential signal.

6. The laser radar according to claim 5, characterized in that: The second differential conversion module includes: a third resistor and a fourth resistor, the first end of the third resistor is coupled to the power supply, the second end of the third resistor is coupled to the first end of the fourth resistor, the digital signal generating unit and the second end of the signal receiving unit respectively; the second end of the fourth resistor is grounded.

7. The laser radar according to claim 5, characterized in that: The amplification factor of the electrical signal amplified by the first differential conversion module and / or the second differential conversion module is adjustable.

8. The laser radar according to claim 2, characterized in that: The signal receiving system further comprises: The DC bias unit is coupled to the signal receiving unit and is configured to provide a DC bias voltage to the signal receiving unit.

9. The laser radar according to claim 8, characterized in that: The DC bias unit comprises: a bias voltage source, a first bias resistor and a second bias resistor, wherein: The bias voltage source is coupled to a first end of the second bias resistor; The second end of the second bias resistor is coupled to the second end of the signal receiving unit; A first end of the first bias resistor is grounded, and a second end thereof is coupled to a first end of the signal receiving unit; The voltage difference between the second end of the first bias resistor and the second end of the second bias resistor is used as the DC bias voltage.

10. The laser radar according to claim 5, characterized in that: The signal receiving system further comprises: a first filtering unit, coupled to the first end of the signal receiving unit and the first end of the first differential conversion module, respectively, and configured to filter out noise of the electrical signal transmitted to the first differential conversion module; The second filtering unit is coupled to the second end of the signal receiving unit and the first end of the second differential conversion module respectively, and is configured to filter out noise of the electrical signal transmitted to the second differential conversion module.

11. The laser radar according to claim 10, characterized in that: The first filtering unit comprises a first filter, a first end of the first filter is coupled to the first end of the signal receiving unit, and a second end of the first filter is coupled to the first end of the first differential conversion module; The second filtering unit includes a second filter, a first end of the second filter is coupled to the second end of the signal receiving unit, and a second end of the second filter is coupled to the first end of the second differential conversion module.

12. The laser radar according to claim 10, characterized in that: The first filtering unit comprises a first capacitor, a first end of the first capacitor is respectively coupled to the first end of the signal receiving unit and the first end of the first differential conversion module, and a second end thereof is grounded; The second filtering unit includes a second capacitor, a first end of the second capacitor is respectively coupled to the second end of the signal receiving unit and the first end of the second differential conversion module, and a second end of the second capacitor is grounded.

13. The laser radar according to claim 2, characterized in that: The signal receiving system further comprises: a first DC isolation unit, coupled to the first end of the signal receiving unit and the first differential circuit respectively, and configured to isolate a DC component in the electrical signal transmitted to the first differential circuit; The second DC isolation unit is coupled to the second end of the signal receiving unit and the second differential circuit respectively, and is configured to isolate the DC component of the electrical signal transmitted to the second differential circuit.

14. The laser radar according to claim 2, characterized in that: The digital signal generating unit includes a comparison module, which is configured to output a first digital signal when the voltage corresponding to the first differential signal is greater than the voltage corresponding to the second differential signal; and output a second digital signal when the voltage corresponding to the first differential signal is less than the voltage corresponding to the second differential signal.

15. The laser radar according to claim 2, characterized in that: The signal receiving unit includes a photodetector.

16. The laser radar according to claim 2, characterized in that: The signal receiving system further comprises: The third filtering unit is disposed between the differential unit and the signal receiving unit and is configured to filter out noise in the electrical signal.

17. The laser radar according to claim 16, characterized in that: The third filtering unit includes a common mode inductor.

18. The laser radar according to claim 1, characterized in that: Also includes: The data processing system is coupled to the signal receiving system and is configured to process the digital signal to obtain the information carried by the optical signal.

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