Signal processing apparatus, detection apparatus and terminal device

Abstract

A signal processing apparatus, a detection apparatus and a terminal device, which relate to the technical field of detection, and are used for reducing the costs and footprint of optical delay lines. The signal processing apparatus comprises a first frequency-modulated optoelectronic circuit and a second frequency-modulated optoelectronic circuit, wherein the first frequency-modulated optoelectronic circuit and the second frequency-modulated optoelectronic circuit share the same optical delay element, the optical delay element comprising a first optical delay line. After being split by a first beam splitting element in the first frequency-modulated optoelectronic circuit, a signal to be delayed enters the first optical delay line from a first end thereof and is output from a second end thereof, and after being split by a first beam splitting element in the second frequency-modulated optoelectronic circuit, a signal to be delayed enters the first optical delay line from the second end thereof and is output from the first end thereof. Making signals to be delayed of two frequency-modulated optoelectronic circuits propagate in opposite directions in the same optical delay line enables the two frequency-modulated optoelectronic circuits to share the same optical delay line, thereby reducing the number of optical delay lines required in the signal processing apparatus, and thus reducing the costs and footprint of the optical delay lines.

Description

A signal processing device, a detection device and a terminal device

[0001] Cross-reference to Related Applications

[0002] This application claims priority to the Chinese patent application No. 202411118437.5, filed on August 15, 2024, and entitled "A signal processing device, a detection device and a terminal device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the technical field of detection, and in particular to a signal processing device, a detection device and a terminal device. BACKGROUND

[0004] The frequency modulated continuous wave (FMCW) LiDAR in the direct modulation mode is currently a mainstream LiDAR, which uses a method of directly changing the frequency of the laser emitter to realize the detection of distance and speed. As shown in FIG. 1a, in an ideal case, the frequency of the modulation signal (L1) input into the FMCW LiDAR has a linear relationship with time, and this linear relationship is linearly reflected on the frequency of the laser emitter, so that the frequency change (L2) of the laser emitter also has a linear relationship with time.

[0005] However, in the frequency modulation process, due to the influence of the internal physical mechanism of the laser (such as imperfect manufacturing process, thermal effect and other factors), the input modulation signal L1 in the laser and the frequency of the laser emitter beam may have a non-linear relationship, which in turn causes the frequency change L2 of the laser emitter beam with time to also have a non-linear relationship, that is, the frequency modulation nonlinearity phenomenon occurs, as shown in FIG. 1b. The frequency modulation nonlinearity phenomenon will affect the measurement accuracy of the FMCW LiDAR. To solve this problem, the input modulation signal L1 in the laser needs to be calibrated. However, the current mainstream calibration scheme usually uses an asymmetric Mach-Zehnder interferometer (AMZI) structure based on an optical delay line, which requires a large number of optical delay lines, especially in the case of a large number of lasers, the number of optical delay lines is multiplied, so a large number of optical delay lines will occupy a very large space in the FMCW LiDAR, and the hardware cost will also be very high.

[0006] In summary, how to reduce the cost and space occupied by the optical delay line is a technical problem that needs to be solved in the field of FMCW LiDAR. SUMMARY

[0007] The application provides a signal processing device, a detection device and a terminal device, which can reduce the cost and space occupied by the optical delay line.

[0008] In a first aspect, the application provides a signal processing device, comprising a first frequency-modulated optoelectronic circuit and a second frequency-modulated optoelectronic circuit, each of the first frequency-modulated optoelectronic circuit and the second frequency-modulated optoelectronic circuit comprising an optical source, a first light splitting element, an optical delay element, a frequency mixer, an optical detection element, a processing element and a driving circuit. The first frequency-modulated optoelectronic circuit and the second frequency-modulated optoelectronic circuit share the same optical delay element, which comprises a first optical delay line having a first end and a second end. The to-be-delayed signal split by the first light splitting element in the first frequency-modulated optoelectronic circuit enters the first end of the first optical delay line, and after being processed by the first optical delay line, the signal is output from the second end of the first optical delay line and enters the frequency mixer in the first frequency-modulated optoelectronic circuit. The to-be-delayed signal split by the first light splitting element in the second frequency-modulated optoelectronic circuit enters the second end of the first optical delay line, and after being processed by the first optical delay line, the signal is output from the first end of the first optical delay line and enters the frequency mixer in the second frequency-modulated optoelectronic circuit.

[0009] Based on the above structure, by making the to-be-delayed signals of the two frequency-modulated optoelectronic circuits transmit in the same optical delay line in opposite directions, the two frequency-modulated optoelectronic circuits can share the same optical delay line, so that the number of optical delay lines required to be arranged in the signal processing device can be reduced, the volume and space occupied by the optical delay line can be reduced, and the hardware cost of the signal processing device can be saved. Further, when the above signal processing device is applied to a detection device (such as a FMCW LiDAR), the length and cost of the optical delay line required to be arranged in the FMCW LiDAR can be reduced, so that the system architecture of the FMCW LiDAR can be simplified, and the system cost of the FMCW LiDAR can be reduced.

[0010] It should be noted that although the to-be-delayed signals of the two frequency-modulated optoelectronic circuits are reversely transmitted in the same optical delay line, based on the interference characteristics and independence of light, the two beams of light will only interfere with each other when they intersect, and will restore the original characteristics after leaving the intersection area. Therefore, whether the to-be-delayed signals of the two frequency-modulated optoelectronic circuits are the same or not, the to-be-delayed signals will restore the original frequency, phase, wavelength and direction after leaving the optical delay line, and continue to propagate forward. That is to say, whether the to-be-delayed signals of the two frequency-modulated optoelectronic circuits are the same or not will not affect the function implementation of the two frequency-modulated optoelectronic circuits. Based on this, the to-be-delayed signals of the above two frequency-modulated optoelectronic circuits can be signals with completely same characteristics, such as signals with same frequency, wavelength, phase and wave emission time, or signals with at least one different characteristic, such as signals with different wavelengths, signals with different phases, signals with different frequencies, etc. The present application does not make specific limitation on this.

[0011] In a possible design, in each frequency-modulated optoelectronic circuit: the optical signal output by the light source enters the optical delay element after being split by the first light splitting element, enters the frequency mixer after being delayed by the optical delay element, is detected by the optical detection element after being mixed by the frequency mixer, and is converted into an electrical signal, the electrical signal is processed by the processing element to obtain a feedback signal and input into the driving circuit, and the feedback signal is used to calibrate the linearity between the modulation signal input into the driving circuit and the optical signal output by the light source.

[0012] Based on the above design, the light source can output an optical signal conforming to the linear variation rule under the action of the modulation signal. After the optical signal is split into the target measurement path, the detection accuracy of the target measurement path can be improved.

[0013] In a possible design, the optical delay element can also have the elements in structure one to structure three:

[0014] Structure one, the optical delay element further includes a first optical transmission element, the first optical transmission element includes a first end, a second end and a third end, the first end to the second end and the second end to the third end are unidirectional transmission, the first end of the first optical transmission element is connected to the first light splitting element in the first frequency-modulated optoelectronic circuit, the second end of the first optical transmission element is connected to the first end of the first optical delay line, and the third end of the first optical transmission element is connected to the frequency mixer in the second frequency-modulated optoelectronic circuit. Based on structure one, the unidirectional transmission characteristics of the three-port first optical transmission element can be used to make the to-be-delayed signal of the first frequency-modulated optoelectronic circuit enter the first optical delay line as much as possible for delay processing, and make the delayed signal of the second frequency-modulated optoelectronic circuit enter the frequency mixer of the second frequency-modulated optoelectronic circuit as much as possible for mixing operation, so as to improve the utilization rate of the signal;

[0015] Structure two, the optical delay element further comprises a second optical transmission element, the second optical transmission element comprises a first end, a second end and a third end, the first end to the second end and the second end to the third end are unidirectional transmission, the first end of the second optical transmission element is connected to the first light splitting element in the second frequency modulation optoelectronic circuit, the second end of the second optical transmission element is connected to the second end of the first optical delay line, and the third end of the second optical transmission element is connected to the frequency mixer in the first frequency modulation optoelectronic circuit. Based on structure two, the unidirectional transmission characteristics of the three-port second optical transmission element can be used to make the to-be-delayed signal of the second frequency modulation optoelectronic circuit enter the first optical delay line as much as possible for delay processing, and make the delayed signal of the first frequency modulation optoelectronic circuit enter the frequency mixer of the first frequency modulation optoelectronic circuit as much as possible to participate in the frequency mixing operation, so as to improve the utilization rate of the signal.

[0016] Structure three, the optical delay element further comprises a first optical transmission element and a second optical transmission element, the first optical transmission element refers to the design in the above structure one, and the second optical transmission element refers to the design in the above structure two. Based on structure three, the unidirectional transmission characteristics of the three-port first optical transmission element and the three-port second optical transmission element can be used to make the to-be-delayed signal of the first frequency modulation optoelectronic circuit enter the first optical delay line as much as possible for delay processing, make the delayed signal of the first frequency modulation optoelectronic circuit enter the frequency mixer of the first frequency modulation optoelectronic circuit as much as possible to participate in the frequency mixing operation, make the to-be-delayed signal of the second frequency modulation optoelectronic circuit enter the first optical delay line as much as possible for delay processing, and make the delayed signal of the second frequency modulation optoelectronic circuit enter the frequency mixer of the second frequency modulation optoelectronic circuit as much as possible to participate in the frequency mixing operation, so as to further improve the utilization rate of the signal.

[0017] Based on the above structure three, the signal processing device can further have a plurality of first frequency modulation optoelectronic circuits or a plurality of second frequency modulation optoelectronic circuits, for example:

[0018] Case one, the first frequency modulation optoelectronic circuit has N, N is an integer greater than or equal to 2, in this case, the signal processing device further comprises a first light combining element and a second light splitting element, the N first light splitting elements in the N first frequency modulation optoelectronic circuits are connected to the N input ends of the first light combining element one by one, the output end of the first light combining element is connected to the first end of the first optical transmission element, the input end of the second light splitting element is connected to the third end of the second optical transmission element, and the N output ends of the second light splitting element are connected to the N frequency mixers in the N first frequency modulation optoelectronic circuits one by one. Based on case one, a plurality of first frequency modulation optoelectronic circuits and one second frequency modulation optoelectronic circuit can share the same optical delay line, so that the number of optical delay lines that need to be arranged in the signal processing device can be further saved, and the delay time of the plurality of first frequency modulation optoelectronic circuits and the one second frequency modulation optoelectronic circuit on the optical signal is not reduced, and the extremely simple architecture and extremely low cost of the signal processing device can be realized;

[0019] Case two, the second frequency modulation optoelectronic circuit has M, M is an integer greater than or equal to 2, in this case, the signal processing device further comprises a second light combining element and a third light splitting element, the M input ends of the second light combining element are connected one by one to the M first light splitting elements in the M second frequency modulation optoelectronic circuits, the output end of the second light combining element is connected to the first end of the second light transmission element, the input end of the third light splitting element is connected to the third end of the first light transmission element, and the M output ends of the third light splitting element are connected one by one to the M mixers in the M second frequency modulation optoelectronic circuits. Based on case two, multiple second frequency modulation optoelectronic circuits and one first frequency modulation optoelectronic circuit can share the same optical delay line, which can further save the number of optical delay lines that need to be set in the signal processing device, and also does not reduce the delay time of the multiple second frequency modulation optoelectronic circuits and the first frequency modulation optoelectronic circuit to the optical signal, and can realize the extremely simple architecture and extremely low cost of the signal processing device;

[0020] Case three, the first frequency modulation optoelectronic circuit has N, and the second frequency modulation optoelectronic circuit has M, N and M are integers greater than or equal to 2, in this case, the signal processing device further comprises a first light combining element, a second light splitting element, a second light combining element and a third light splitting element, the first light combining element and the second light splitting element refer to the design in case one, and the second light combining element and the third light splitting element refer to the design in case two. Based on case three, multiple first frequency modulation optoelectronic circuits and multiple second frequency modulation optoelectronic circuits can share the same optical delay line, which can further save the number of optical delay lines that need to be set in the signal processing device, and realize the extremely simple architecture and extremely low cost of the signal processing device.

[0021] In a possible design, the optical delay element can also have the elements in structure four as follows:

[0022] Structure four, the optical delay element further comprises a third light transmission element and a fourth light transmission element, the third light transmission element and the fourth light transmission element each comprise a first end, a second end, a third end and a fourth end, the first end to the second end, the second end to the third end, the third end to the fourth end, and the fourth end to the first end are unidirectional transmission; the first end of the third light transmission element is connected to the first light splitting element in the first frequency modulation optoelectronic circuit, the second end of the third light transmission element is connected to the first end of the first optical delay line, the third end of the third light transmission element is connected to the third end of the fourth light transmission element, and the fourth end of the third light transmission element is connected to the mixer in the first frequency modulation optoelectronic circuit; the first end of the fourth light transmission element is connected to the first light splitting element in the second frequency modulation optoelectronic circuit, the second end of the fourth light transmission element is connected to the second end of the first optical delay line, and the fourth end of the fourth light transmission element is connected to the mixer in the second frequency modulation optoelectronic circuit.

[0023] Based on the above structure four, the one-way transmission characteristics of the third four-port optical transmission element and the fourth four-port optical transmission element can be utilized to make the to-be-delayed signal of the first frequency-modulated optoelectronic circuit enter the first optical delay line for delay processing as much as possible, the delayed signal of the first frequency-modulated optoelectronic circuit enters the frequency mixer of the first frequency-modulated optoelectronic circuit for frequency mixing operation as much as possible, and the to-be-delayed signal of the second frequency-modulated optoelectronic circuit enters the first optical delay line for delay processing as much as possible, and the delayed signal of the second frequency-modulated optoelectronic circuit enters the frequency mixer of the second frequency-modulated optoelectronic circuit for frequency mixing operation as much as possible, so as to further improve the utilization rate of the signal.

[0024] In one example of the above structure four, the third optical transmission element includes a first sub-optical transmission element and a second sub-optical transmission element, and each of the first sub-optical transmission element and the second sub-optical transmission element includes a first end, a second end, and a third end, and the first end to the second end, the second end to the third end, and the third end to the first end are unidirectional transmission; the first end of the first sub-optical transmission element is the first end of the third optical transmission element, the second end of the first sub-optical transmission element is connected to the first end of the second sub-optical transmission element, and the third end of the first sub-optical transmission element is the fourth end of the third optical transmission element; the second end of the second sub-optical transmission element is the second end of the third optical transmission element, and the third end of the second sub-optical transmission element is the third end of the third optical transmission element.

[0025] Based on the above example, two three-port sub-transmission elements can be utilized to realize the function of the third four-port optical transmission element.

[0026] In one example of the above structure four, the fourth optical transmission element includes a third sub-optical transmission element and a fourth sub-optical transmission element, and each of the third sub-optical transmission element and the fourth sub-optical transmission element includes a first end, a second end, and a third end, and the first end to the second end, the second end to the third end, and the third end to the first end are unidirectional transmission; the first end of the third sub-optical transmission element is the first end of the fourth optical transmission element, the second end of the third sub-optical transmission element is connected to the first end of the fourth sub-optical transmission element, and the third end of the third sub-optical transmission element is the fourth end of the fourth optical transmission element; the second end of the fourth sub-optical transmission element is the second end of the fourth optical transmission element, and the third end of the fourth sub-optical transmission element is the third end of the fourth optical transmission element.

[0027] Based on the above example, two three-port sub-transmission elements can be utilized to realize the function of the fourth four-port optical transmission element.

[0028] In one example of the above structure four, the optical delay element can further include a second optical delay line, and the second optical delay line is arranged on the connection line between the third end of the third optical transmission element and the third end of the fourth optical transmission element.

[0029] Based on the above examples, the signal to be delayed in any one of the frequency-modulated optoelectronic circuits first passes through the first optical delay line for primary delay and then passes through the second optical delay line for secondary delay, so that the two frequency-modulated optoelectronic circuits can share the same two optical delay lines, if the delay time is the same, the total length of the two optical delay lines does not change, and if the lengths of the optical delay lines are the same, the delay time length can be doubled.

[0030] In one example of the above structure four, the signal processing device can further have a plurality of first frequency-modulated optoelectronic circuits or a plurality of second frequency-modulated optoelectronic circuits, such as:

[0031] Case four, the first frequency-modulated optoelectronic circuit has N, N is an integer greater than or equal to 2, in this case, the optical delay element further includes a third light combining element and a fourth light splitting element, the N input ends of the third light combining element are connected one by one to the N first light splitting elements in the N first frequency-modulated optoelectronic circuits, the output end of the third light combining element is connected to the first end of the third optical transmission element, the input end of the fourth light splitting element is connected to the fourth end of the third optical transmission element, and the N output ends of the fourth light splitting element are connected one by one to the N mixers in the N first frequency-modulated optoelectronic circuits. Based on case four, a plurality of first frequency-modulated optoelectronic circuits and one second frequency-modulated optoelectronic circuit can share the same one or two optical delay lines, so that the number of optical delay lines that need to be set in the signal processing device can be further saved, and an extremely simple architecture and extremely low cost of the signal processing device can be achieved;

[0032] Case five, the second frequency-modulated optoelectronic circuit has M, M is an integer greater than or equal to 2, in this case, the optical delay element further includes a fourth light combining element and a fifth light splitting element, the M input ends of the fourth light combining element are connected one by one to the M first light splitting elements in the M second frequency-modulated optoelectronic circuits, the output end of the fourth light combining element is connected to the first end of the fourth optical transmission element, the input end of the fifth light splitting element is connected to the fourth end of the fourth optical transmission element, and the M output ends of the fifth light splitting element are connected one by one to the M mixers in the M second frequency-modulated optoelectronic circuits. Based on case five, a plurality of second frequency-modulated optoelectronic circuits and one first frequency-modulated optoelectronic circuit can share the same one or two optical delay lines, so that the number of optical delay lines that need to be set in the signal processing device can be further saved, and an extremely simple architecture and extremely low cost of the signal processing device can be achieved;

[0033] In a sixth case, the first frequency modulation optoelectronic circuit has N, and the second frequency modulation optoelectronic circuit has M, where N and M are integers greater than or equal to 2. In this case, the optical delay element further includes a third light combining element, a fourth light splitting element, a fourth light combining element, and a fifth light splitting element. The third light combining element and the fourth light splitting element are designed as described in the fourth case above, and the fourth light combining element and the fifth light splitting element are designed as described in the fifth case above. Based on the fifth case, multiple first frequency modulation optoelectronic circuits and multiple second frequency modulation optoelectronic circuits can share the same one or two optical delay lines, which can further save the number of optical delay lines required to be arranged in the signal processing device, and achieve an extremely simple architecture and extremely low cost of the signal processing device.

[0034] In a possible design, one or more of the first optical transmission element, the second optical transmission element, the third optical transmission element, the fourth optical transmission element, the first sub-optical transmission element, the second sub-optical transmission element, the third sub-optical transmission element, and the fourth sub-optical transmission element is an optical circulator. The optical circulator has low cost and small size, and is easy to implement.

[0035] In a possible design, the first optical delay line and / or the second optical delay line is a fiber delay line or an integrated waveguide delay line on a chip.

[0036] Based on the above design, the signal processing device can be suitable for various optical delay lines, thereby having universality.

[0037] In a possible design, in each frequency modulation optoelectronic circuit: the optical delay element is connected between the first output end of the first light splitting element and the first input end of the frequency mixer, the second output end of the first light splitting element is connected to the second input end of the frequency mixer, the first light splitting element is configured to split the optical signal generated by the light source to obtain the local signal and the to-be-delayed signal, and output the to-be-delayed signal through the first output end and output the local signal through the second output end, and the frequency mixer is configured to mix the local signal and the delayed signal to obtain the intermediate frequency signal.

[0038] Based on the above design, the local signal and the to-be-delayed signal can be obtained by splitting through the first light splitting element to assist the frequency mixer to perform the mixing operation.

[0039] In a possible design, in each frequency modulation optoelectronic circuit: the signal processing device further includes an amplifier and an analog-to-digital converter, the amplifier and the analog-to-digital converter are connected between the light detection element and the processing element, the amplifier is configured to amplify the intermediate frequency signal from the light detection element, and the analog-to-digital converter is configured to perform analog-to-digital conversion on the amplified intermediate frequency signal to obtain the digital signal.

[0040] Based on the above design, the power of the intermediate frequency signal is amplified by the amplifier, which can ensure that the intermediate frequency signal is successfully transmitted to the analog-to-digital conversion element, and the intermediate frequency signal is sampled as a digital signal by the analog-to-digital conversion element, which can facilitate the software analysis of the subsequent processing element.

[0041] In a possible design, in each frequency-modulated optoelectronic circuit: the target measurement path is further connected to the third output end of the first light splitting element, the first light splitting element is further configured to split the light signal generated by the light source to obtain a detection signal, and output the detection signal through the third output end, and the target measurement path is configured to perform target measurement using the detection signal.

[0042] Based on the above design, the signal processing apparatus can not only calibrate the modulation signal output by the driving circuit, but also perform target measurement. By calibrating the frequency-modulated signal output by the driving circuit, the frequency of the light signal emitted by the light source can be made to change linearly with time, and thus the detection signal obtained by splitting the light signal can meet the preset requirements, thereby improving the accuracy of the target measurement path in detecting the target.

[0043] In a possible design, in each frequency-modulated optoelectronic circuit: the first light splitting element includes a first beam splitter and a second beam splitter, the first output end of the first beam splitter is connected to the input end of the second beam splitter, the second output end of the first beam splitter is connected to the target measurement path, the first output end of the second beam splitter is connected to the optical delay element, and the second output end of the second beam splitter is connected to the frequency mixer; the first beam splitter is configured to split the light signal generated by the light source to obtain a detection signal and an intermediate light signal, output the intermediate light signal through the first output end, and output the detection signal through the second output end; and the second beam splitter is configured to split the intermediate light signal to obtain a local signal and a to-be-delayed signal, output the to-be-delayed signal through the first output end, and output the local signal through the second output end.

[0044] Based on the above design, the function of the first light splitting element can be realized by two beam splitters, which are low in cost and small in size, and are helpful to realize the small size and low cost of the signal processing apparatus.

[0045] In a second aspect, the present application provides a detection apparatus, which includes the signal processing apparatus in the first aspect or any design in the first aspect.

[0046] In a third aspect, the present application provides a terminal device, which includes the signal processing apparatus in the first aspect or any design in the first aspect, or includes the detection apparatus in the second aspect.

[0047] The technical effects that can be achieved by the second aspect or the third aspect can be referred to the description of the beneficial effects of the first aspect, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0048] FIG. 1a exemplarily shows a linear relationship between a transmitted light beam and a modulation signal;

[0049] FIG. 1b exemplarily shows a nonlinear relationship between a transmitted light beam and a modulation signal;

[0050] FIG. 2 exemplarily shows a possible application scenario to which the present application is applicable;

[0051] FIG. 3a exemplarily shows a structure of a direct modulation FMCW LiDAR that is currently mainstream;

[0052] FIG. 3b exemplarily shows a structure of a single-laser direct modulation FMCW LiDAR provided by the industry;

[0053] FIG. 3c exemplarily shows a structure of a multi-laser direct modulation FMCW LiDAR provided by the industry;

[0054] FIG. 4 exemplarily shows a structure of a signal processing device provided by the present application;

[0055] FIG. 5a exemplarily shows a structure of a signal processing device provided by embodiment one;

[0056] FIG. 5b exemplarily shows another structure of a signal processing device provided by embodiment one;

[0057] FIG. 5c exemplarily shows yet another structure of a signal processing device provided by embodiment one;

[0058] FIG. 6 exemplarily shows a specific structure of a signal processing device provided by embodiment one;

[0059] FIG. 7a exemplarily shows a specific structure of another signal processing device provided by embodiment one;

[0060] FIG. 7b exemplarily shows a specific structure of yet another signal processing device provided by embodiment one;

[0061] FIG. 8a exemplarily shows a structure of another signal processing device provided by embodiment one;

[0062] FIG. 8b exemplarily shows a structure of yet another signal processing device provided by embodiment one;

[0063] FIG. 8c exemplarily shows a structure of yet another signal processing device provided by embodiment one;

[0064] FIG. 9 exemplarily shows a structure of a signal processing device provided by embodiment two;

[0065] Fig. 10a exemplarily shows a specific structural schematic diagram of a signal processing device provided by the second embodiment;

[0066] Fig. 10b exemplarily shows another specific structural schematic diagram of a signal processing device provided by the second embodiment;

[0067] Fig. 10c exemplarily shows still another specific structural schematic diagram of a signal processing device provided by the second embodiment;

[0068] Fig. 11 exemplarily shows a structural schematic diagram of still another signal processing device provided by the second embodiment;

[0069] Fig. 12 exemplarily shows a structural schematic diagram of still another signal processing device provided by the second embodiment;

[0070] Fig. 13a exemplarily shows a structural schematic diagram of still another signal processing device provided by the second embodiment;

[0071] Fig. 13b exemplarily shows a structural schematic diagram of still another signal processing device provided by the second embodiment;

[0072] Fig. 13c exemplarily shows a structural schematic diagram of still another signal processing device provided by the second embodiment;

[0073] Fig. 14a exemplarily shows a specific structural schematic diagram of a signal processing device provided by the present application;

[0074] Fig. 14b exemplarily shows another specific structural schematic diagram of a signal processing device provided by the present application;

[0075] Fig. 14c exemplarily shows still another specific structural schematic diagram of a signal processing device provided by the present application;

[0076] Fig. 14d exemplarily shows still another specific structural schematic diagram of a signal processing device provided by the present application;

[0077] Fig. 14e exemplarily shows still another specific structural schematic diagram of a signal processing device provided by the present application;

[0078] Fig. 15 exemplarily shows a structural schematic diagram of a detection device provided by the present application;

[0079] Fig. 16 exemplarily shows a structural schematic diagram of a terminal device provided by the present application. DETAILED DESCRIPTION

[0080] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0081] Hereinafter, some terms in the present application are explained. It should be noted that these explanations are for the convenience of understanding by those skilled in the art, and do not constitute a limitation on the scope of protection required by the present application.

[0082] I. Mixing

[0083] Mixing, also known as coherent demodulation, refers to the difference between the frequency and phase of two signals.

[0084] For example, in FMCW LiDAR, the probe signal is usually a linear frequency modulation signal. After the linear frequency modulation signal interacts with the target object, the echo signal (i.e. the received signal) reflected back also has the same frequency variation characteristics, but according to the different distances of the target, the echo signal will produce a certain phase difference and frequency difference relative to the probe signal. Therefore, after receiving the echo signal, the echo signal and the probe signal can be mixed, that is, the frequency and phase of the probe signal and the echo signal are subtracted, thereby obtaining a low-frequency beat signal, which is also called a beat signal or an intermediate frequency signal. The intermediate frequency signal contains the frequency difference information between the two signals, which is proportional to the target distance. At the same time, it also contains the Doppler effect information due to the movement of the target, based on which the speed of the target can be calculated.

[0085] II. Interference characteristics and independence of light

[0086] The interference characteristics of light refer to the phenomenon that two or more beams of light meet in space and form a stable intensity distribution in the overlapping area. However, since the light beams themselves have independence in propagation, as long as the two or more beams of light leave the overlapping area, they will return to the original state of motion unchanged. In other words, the interfering light can be separated into two or more beams of light that did not interfere with each other before, and each beam of light will continue to propagate at the original frequency, direction, and phase.

[0087] The foregoing introduces some terms related to the present application, and the following introduces possible application scenarios of the present application.

[0088] In a possible implementation, the signal processing apparatus provided in the present application can be integrated into a detection apparatus, which can be installed on a vehicle, such as a vehicle, a ship, an airplane, a drone, a train, a subway, an automated guided vehicle (AGV), or a unmanned transport vehicle, etc. For example, referring to FIG. 2, an application scenario of the present application is shown, in which the detection apparatus is installed on the front bumper of a vehicle. The detection apparatus can be used as an information collection source for path planning, to assist the driver to realize or automatically realize safe driving of the vehicle. It can be understood that the detection apparatus can also be installed at any position or multiple positions of the vehicle, such as around the vehicle lamp, around the rearview mirror, near the vehicle door, at the rear bumper of the vehicle, behind the windshield, on the roof, etc., to capture the surrounding environment information of the vehicle. When the detection apparatus is installed behind the windshield, it has a lower requirement for the risk of stone collision, and will not affect the appearance of the vehicle, and the front windshield itself has a window heating and defogging function and a wiper cleaning function.

[0089] It should be understood that the above application scenarios are only examples, and the detection apparatus provided in the present application can also be applied to other possible scenarios, and is not limited to the above examples. For example, the detection apparatus can also be installed on a road side unit (RSU) as a roadside traffic detection apparatus, to realize intelligent vehicle-road cooperative communication. For example, the detection apparatus can also be installed in the cabin of the vehicle as a living body detection apparatus, to find and prompt the user to leave children or pets in the cabin. For another example, the detection apparatus can also be applied to a terminal device or a component provided in the terminal device, such as a smart phone, a smart home device, a smart manufacturing device, a medical device, an industrial device, and a robot, etc. Here, it is not listed one by one. For another example, the detection apparatus can also be applied to

[0090] It should be noted that the application scenarios described in the present application are used to more clearly illustrate the technical solutions of the present application, and do not limit the technical solutions provided in the present application.

[0091] In addition, the above application scenarios can be applied to the fields of unmanned driving, assisted driving, intelligent driving, automatic driving, networked vehicles, optical communication, security monitoring, biological medicine, surveying and mapping (such as three-dimensional mapping and remote sensing mapping), meteorological research, biomass and vegetation research, air quality monitoring, and aerospace applications, etc.

[0092] The above detection apparatus can include, but is not limited to, a LiDAR, such as a direct modulation FMCW LiDAR, which is referred to as a direct modulation FMCW LiDAR. Before introducing the specific solutions provided in the present application, the related content of the direct modulation FMCW LiDAR will be introduced first.

[0093] As shown in FIG. 3a, a schematic diagram of a direct modulation FMCW LiDAR currently in the mainstream is shown, which includes a light source, a light splitting element, a target measurement path, a reference calibration path, and a driving circuit. The reference calibration path is connected to one output end of the light splitting element, and the target measurement path is connected to the other output end of the light splitting element. When the direct modulation FMCW LiDAR is working, the driving circuit can generate a modulation signal (L1) and input the modulation signal L1 to the light source. The modulation signal L1 can drive the light source to emit an optical signal S with a linearly changing frequency over time. The light splitting element splits the optical signal S into a probe signal and a calibration signal, and outputs the probe signal to the target measurement path and outputs the calibration signal to the reference calibration path. The target measurement path performs target measurement based on the probe signal to obtain distance, speed, and other information of the target. The reference calibration path generates a feedback signal (P) based on the calibration signal and outputs the feedback signal P to the driving circuit. The driving circuit calibrates the output modulation signal L1 based on the feedback signal P, so that the frequency change of the optical signal S emitted by the light source is linear with the input modulation signal L1 of the light source.

[0094] Exemplarily, taking the light source as a laser and the light splitting element as a beam splitter 1 as an example, please refer to FIG. 3b, a schematic diagram of a specific structure of a single-laser direct modulation FMCW LiDAR is shown. In this example, the reference calibration path can include a beam splitter 2, an optical delay line, a frequency mixer, an optical detection element, and a processing element. The laser emits a laser beam S according to the modulation signal L1 input by the driving circuit, the beam splitter 1 splits the laser beam S into a probe signal and a calibration signal. The probe signal is input to the target measurement path for target measurement, and the calibration signal is input to the beam splitter 2. The beam splitter 2 splits the calibration signal into a to-be-delayed signal light and a calibration local oscillator light, wherein the calibration local oscillator light is directly input to the frequency mixer, and the to-be-delayed signal light is input to the frequency mixer after delay processing by the optical delay line. The frequency mixer mixes the calibration local oscillator light and the delayed signal light to obtain an intermediate frequency signal. The optical detection element detects the intermediate frequency signal and inputs the detected intermediate frequency signal to the processing element. The processing element processes the intermediate frequency signal to obtain a feedback signal P and inputs the feedback signal P to the driving circuit. The driving circuit adjusts the modulation signal L1 output to the laser according to the input feedback signal P.

[0095] Based on the single-laser direct modulation FMCW LiDAR architecture shown in FIG. 3b, it is extended to a multi-laser scenario, and the structure is shown in FIG. 3c. It can be known that in the multi-laser direct modulation FMCW LiDAR, a plurality of optical delay lines need to be set, and the number of the plurality of optical delay lines is one-to-one corresponding to the number of the plurality of lasers. Therefore, if it is extended to a P (P≥2) laser direct modulation FMCW LiDAR, the length of the optical delay line needs to be P times of the length of the optical delay line in the single-laser direct modulation FMCW LiDAR. In the single-laser direct modulation FMCW LiDAR, the length of the optical delay line is related to the required delay time, which is generally on the order of meters. The length itself is already relatively long, and if it is extended to P lasers, the optical delay line on the order of meters multiplied by P times will have a very large size and hardware cost, occupying a large space in the FMCW LiDAR.

[0096] Therefore, the present application provides a signal processing device, which reversely transmits two paths or two groups of to-be-delayed signals in the same one or more optical delay lines, so as to utilize the same one or more optical delay lines to delay the two paths or two groups of to-be-delayed signals. When the signal processing device is applied to a multi-laser direct modulation FMCW LiDAR, the plurality of reference calibration paths corresponding to the plurality of lasers can share the same one or more optical delay lines, the number of the optical delay lines is greatly reduced, the size and hardware cost of the optical delay lines are reduced, and the occupied space of the optical delay lines in the direct modulation FMCW LiDAR is also correspondingly reduced.

[0097] The signal processing device provided by the present application will be described in detail below in combination with FIGS. 4 to 14e.

[0098] It should be noted that in the drawings of the present application, two devices are connected by a “dashed line”, which represents that the two devices are connected by an optical medium, such as an optical fiber, a waveguide or any medium that can transmit an optical signal. In summary, the two devices connected by the “dashed line” can transmit an optical signal. Similarly, two devices are connected by a “solid line”, which represents that the two devices are connected by an electrical medium (also referred to as an electrical connection), such as a cable, a wire or any medium that can transmit an electrical signal. In summary, the two devices connected by the “solid line” can transmit an electrical signal.

[0099] Please refer to Figure 4, which shows a schematic diagram of the structure of a signal processing device provided in this application. The signal processing device includes a first frequency-modulated photoelectric circuit 110 and a second frequency-modulated photoelectric circuit 210. Each frequency-modulated photoelectric circuit in the first frequency-modulated photoelectric circuit 110 and the second frequency-modulated photoelectric circuit 210 includes a light source, a first beam splitter, an optical delay element 300, a mixer, a photodetector, a processing element, and a driving circuit. For example, the first frequency-modulated photoelectric circuit 110 includes a light source 111, a first beam splitter 112, an optical delay element 300, a mixer 114, a photodetector 115, a processing element 116, and a driving circuit 117. The second frequency-modulated photoelectric circuit 210 includes a light source 211, a first beam splitter 212, an optical delay element 300, a mixer 214, a photodetector 215, a processing element 216, and a driving circuit 217. The first frequency-modulated photoelectric circuit 110 and the second frequency-modulated photoelectric circuit 210 share the same optical delay element 300, which includes a first optical delay line 310 having a first end (a1) and a second end (a2). The signal to be delayed (S) after being split by the first beam-splitting element 112 in the first frequency-modulated photoelectric circuit 110... 11 The signal enters the first optical delay line 310 from the first end a1, and after being delayed by the first optical delay line 310, it becomes the delayed signal S. 11 ', after delay signal S 11 The signal output from the second end a2 of the first optical delay line 310 enters the mixer 114 in the first frequency modulation optoelectronic circuit 110. The signal to be delayed (S) after being split by the first beam splitter 212 in the second frequency modulation optoelectronic circuit 210... 21 The signal enters the first optical delay line 310 from the second end a2, and after being delayed by the first optical delay line 310, it becomes the delayed signal S. 21 ', after delay signal S 21 The output from the first end a1 of the first optical delay line 310 enters the mixer 214 in the second frequency modulation optoelectronic circuit 210.

[0100] Based on the above scheme, the delay signal S of the first frequency modulation photoelectric circuit 110 11 The delay signal S of the second frequency modulation photoelectric circuit 210 21 The signals will be transmitted in reverse within the same first optical delay line 310, thus allowing the same first optical delay line 310 to be reused to delay the signals S to be transmitted between the two frequency-modulated optoelectronic circuits. 11 and S 21 The delay can reduce the number of optical delay lines required in the signal processing device, thereby reducing the cost and space occupied by optical delay lines.

[0101] It should be noted that based on the interference characteristics and independence of light, the two beams of light will only interfere with each other when intersecting, and will restore the original characteristics after leaving the intersection area. Therefore, whether the two to-be-delayed signals S 11 and S 21 are the same, both will restore the original frequency, phase, wavelength and direction after leaving the first optical delay line 310 and continue to propagate forward. That is to say, whether the two to-be-delayed signals S 11 and S 21 are the same, it will not affect the function implementation of the first frequency-modulated optoelectronic circuit 110 and the second frequency-modulated optoelectronic circuit 210. Based on this, the above two to-be-delayed signals S 11 and S 21 may be signals with completely identical characteristics, such as signals with the same frequency, wavelength, phase and wave emission time, or signals with at least one different characteristic, such as signals with different wavelengths, signals with different phases, signals with different frequencies, etc. In other words, the light source 111 and the light source 211 can emit light signals with the same or different characteristics at the same time or at different times, which is not limited in the present application.

[0102] In the above scheme, the frequency-modulated optoelectronic circuit can be understood as a loop formed by signal transmission between internal elements. For example, taking the first frequency-modulated optoelectronic circuit 110 as an example, as shown in FIG. 4, the signal transmission process of the circuit is as follows: the light signal S output by the light source 111 enters the first light splitting element 112; the first light splitting element 112 splits the light signal S into the to-be-delayed signal S 11 and other light signals (not shown in the figure, and details can be referred to the following content); the to-be-delayed signal S 11 enters the optical delay element 300 for delay processing, and then enters the frequency mixer 114 for frequency mixing with other signals (not shown in the figure, and details can be referred to the following content) to obtain the intermediate frequency signal Z; the intermediate frequency signal Z is detected by the optical detection element 115 and output to the processing element 116; the processing element 116 sends the feedback signal P to the driving circuit 117 according to the detected intermediate frequency signal Z; the driving circuit 117 adjusts the modulation signal L1 output to the light source 111 according to the feedback signal P to calibrate the linearity between the modulation signal L1 and the light signal S output by the light source 111.

[0103] Based on the signal transmission process in the above loop, the to-be-delayed signal S 11 (referred to as the first to-be-delayed signal S 11 ) in the first frequency-modulated optoelectronic circuit 110 and the to-be-delayed signal S 21 (referred to as the second to-be-delayed signal S 21 ) in the second frequency-modulated optoelectronic circuit 210 will be transmitted in opposite directions on the same first optical delay line 310, and therefore the first end a1 of the first optical delay line 310 will receive the first to-be-delayed signal S11 , the second delayed signal (referred to as second delayed signal S 21 ') in the second FM photoelectric circuit 210 will also be emitted, and the second end a2 of the first optical delay line 310 will receive the second delayed signal S 21 , the delayed signal (referred to as first delayed signal S 11 ') in the first FM photoelectric circuit 110 will also be emitted.

[0104] To ensure that the first delayed signal S 11 ' can smoothly enter the mixer 114, and the second delayed signal S 21 ' can smoothly enter the mixer 214, in one example, as shown in FIG. 4, two lines can be arranged on the first end a1 side and the second end a2 side of the first optical delay line 310 respectively, one of the lines on the first end a1 side is connected to the first light splitting element 112 (referred to as first line), and the other line is connected to the mixer 214 (referred to as second line), one of the lines on the second end a2 side is connected to the first light splitting element 212 (referred to as third line), and the other line is connected to the mixer 114 (referred to as fourth line). In this way, after the first delayed signal S 11 ' output from the second end a2 of the first optical delay line 310 to the right, at least a part of it will be transmitted from the fourth line to the mixer 114 to participate in the mixing operation in the first FM photoelectric circuit 110. Similarly, after the second delayed signal S 21 ' output from the first end a1 of the first optical delay line 310 to the left, at least a part of it will be transmitted from the second line to the mixer 214 to participate in the mixing operation in the second FM photoelectric circuit 210.

[0105] However, using the structure design in the above example, there will also be a part of the first delayed signal S 11 ' transmitted from the third line to the first light splitting element 212, and a part of the second delayed signal S 21 ' transmitted from the first line to the first light splitting element 112, thereby causing signal waste. To alleviate the problem of signal waste, in some embodiments, a unidirectional optical transmission element can be arranged on the first end a1 side and / or the second end a2 side of the first optical delay line 310 to control the transmission direction of the signal. The unidirectional optical transmission element can be a three-port element, a four-port element, or an element with more ports, or it can also be a combination of multiple-port elements, which is not limited in particular.

[0106] Exemplarily, two possible setting manners of the light transmission element are given below through Embodiment One and Embodiment Two. It should be understood that the following two embodiments are only examples, and other light transmission elements can also exist in other schemes, which are not limited in the present application.

[0107] Embodiment One

[0108] In Embodiment One, the three-port light transmission element can be arranged on the side of the first end a1 and / or the second end a2 of the first light delay line 310 to control the transmission direction of the signal.

[0109] For example, referring to FIGS. 5a-5c, three possible setting manners of the light transmission element provided by Embodiment One are shown:

[0110] Setting Manner One

[0111] As shown in FIG. 5a, the light delay element 300 can further include a first light transmission element 321, which includes a first end (b 11 ), a second end (b 12 ) and a third end (b 13 ). The first end b 11 is connected to the first light splitting element 112 in the first frequency modulation optoelectronic circuit 110, the second end b 12 is connected to the first end a1 of the first light delay line 310, and the third end b 13 is connected to the frequency mixer 214 in the second frequency modulation optoelectronic circuit 210. The first end b 11 to the second end b 12 , the second end b 12 to the third end b 13 is unidirectional transmission.

[0112] Based on this setting manner, in the first frequency modulation optoelectronic circuit 110, the first to-be-delayed signal S 11 split by the first light splitting element 112 will enter the first end b 11 of the first light transmission element 321. Since the first end b 11 to the second end b 12 is unidirectional transmission, the first to-be-delayed signal S 11 will be output from the second end b 12 of the first light transmission element 321 to the first light delay line 310, but not from the third end b 13 of the first light transmission element 321, so that the first to-be-delayed signal S 11 can be transmitted to the first light delay line 310 for delay processing in whole or almost in whole.

[0113] Similarly, in the second frequency-modulated photoelectric circuit 210, the second delayed signal S, after being delayed by the first optical delay line 310, 21 It will enter the second end b of the first optical transmission element 321 12 Because of the second end b 12 To the third end b 13 It is a unidirectional transmission; therefore, after the second delay, the signal S... 21 'It will come from the third end b of the first optical transmission element 321' 13 The output is sent to mixer 214, and not from the first end b of the first optical transmission element 321. 11 Output, thus, the second delayed signal S 21 It can transmit all or almost all of the data to mixer 214 to participate in the mixing operation.

[0114] Setting Method 2

[0115] As shown in Figure 5b, the optical delay element 300 may further include a second optical transmission element 322, the second optical transmission element 322 including a first end (b) 21 ), second end (b) 22 ) and the third end (b 23 ), first end b 21 Connect the first beam splitter 212 in the second frequency modulation photoelectric circuit 210, the second end b 22 Connect the second end a2 and the third end b of the first optical delay line 310 23 The mixer 114 in the first frequency modulation photoelectric circuit 110 is connected to the first terminal b. 21 To the second end b 22 Second end b 22 To the third end b 23 It is a one-way transmission.

[0116] Based on this configuration, in the second frequency-modulated photoelectric circuit 210, the second delay signal S after being split by the first beam splitter 212... 21 It will enter the first end b of the second optical transmission element 322 21 Because of the first end b 21 To the second end b 22 It is a unidirectional transmission; therefore, the second delay signal S... 21 It will be from the second end b of the second optical transmission element 322 22 The output is sent to the first optical delay line 310, and not from the third end b of the second optical transmission element 322. 23 Output, thus, the second delay signal S 21 It can transmit all or almost all of the data to the first optical delay line 310 for delay processing.

[0117] Similarly, in the first frequency-modulated optoelectronic circuit 110, the first delayed signal S 11 will enter the second end b 22 of the second optical transmission element 322 22 Since the second end b 23 is unidirectional transmission, the first delayed signal S 11 will be output from the third end b 23 of the second optical transmission element 322 to the frequency mixer 114, and will not be output from the first end b 21 of the second optical transmission element 322, so that the first delayed signal S 11 can be transmitted to the frequency mixer 114 for mixing operation.

[0118] Setting mode three

[0119] As shown in FIG. 5c, the optical delay element 300 can further include a first optical transmission element 321 and a second optical transmission element 322. The first optical transmission element 321 is as described above in the first setting mode, and the second optical transmission element 322 is as described above in the second setting mode.

[0120] Based on this setting mode, in the first frequency-modulated optoelectronic circuit 110, the first delayed signal S 11 obtained by the first light splitting element 112 can be transmitted to the first optical transmission element 321 through the first end b 11 and the second end b 12 in sequence, and can be transmitted to the first optical delay line 310 for delay processing, and the first delayed signal S 11 processed by the first optical delay line 310 can be transmitted to the second optical transmission element 322 through the second end b 22 and the third end b 23 in sequence, and can be transmitted to the frequency mixer 114 for mixing operation. In this way, the signal transmission waste in the first frequency-modulated optoelectronic circuit 110 can be maximized, and the signal transmission efficiency in the first frequency-modulated optoelectronic circuit 110 can be improved.

[0121] Similarly, in the second frequency-modulated optoelectronic circuit 210, the second delayed signal S 21 obtained by the first light splitting element 212 can be transmitted to the second optical transmission element 322 through the first end b 21 and the second end b 22 in sequence, and can be transmitted to the first optical delay line 310 for delay processing, and the second delayed signal S 21 processed by the first optical delay line 310 can be transmitted to the first optical transmission element 321 through the second end b 12 and the third end b 13Then, all or almost all of the signal can be transmitted to mixer 214 to participate in the mixing operation. In this way, the signal transmission waste in the second frequency modulation optoelectronic circuit 210 can be maximized and the signal transmission efficiency in the second frequency modulation optoelectronic circuit 210 can be improved.

[0122] All three configuration methods described above involve placing a three-port optical transmission element on one side of the first end a1 and / or the second end a2 of the first optical delay line 310. This three-port optical transmission element can be a circulator, an isolator, or a coupler. Although a coupler cannot transmit the entire delayed signal to the mixer, by setting the interference parameters of each port on the coupler, the input and output signals of each port can be proportionally adjusted, thereby ensuring that most of the delayed signal is transmitted to the mixer. Of course, this three-port optical transmission element can also be other devices, which are not specifically limited here.

[0123] For ease of understanding, the following description uses the configuration shown in Figure 5c as an example to further illustrate other components and functions in the signal processing device. However, it should be understood that the relevant structures and functions are also applicable to the structures shown in Figure 5a or Figure 5b, and will not be repeated here.

[0124] Optionally, based on the structure shown in Figure 5c, please refer to Figure 6, which shows a schematic diagram of another signal processing device provided in Embodiment 1. In this example, in each frequency-modulated photoelectric circuit, the first beam splitter can split the optical signal output from the light source to obtain a local oscillator signal and a signal to be delayed. The local oscillator signal is directly input to the mixer, while the signal to be delayed is first delayed by the optical delay element 300 before being input to the mixer. For example, taking the first frequency-modulated photoelectric circuit 110 as an example, the first beam splitter 112 can have a first output terminal (c 11 ) and second output terminal (c 12 The mixer 114 may have a first input terminal (d) 11 ) and second input terminal (d 12 The first output terminal c of the first beam splitter 112 11 The first end b of the first optical transmission element 321 11 Second output terminal c 12 Connect to the second input terminal d of mixer 114 12 The third end b of the second optical transmission element 322 23 Connect the first input terminal d of mixer 114 11 After the light source 111 outputs the optical signal S, the first beam splitter 112 can perform beam splitting processing on the optical signal S to obtain the first delay signal S. 11 And the calibration path local oscillator signal, the first beam splitter 112 through its first output terminal c 11 Output the first delay signal S11 and through its second output end c 12 The calibration path local oscillator signal is output. The calibration path local oscillator signal directly enters the second input end d 12 of the mixer 114 11 , and the first to-be-delayed signal S 11 passes through the optical delay element 300 for delay processing and then enters the first input end d 11 of the mixer 114 11 . The mixer 114 receives the first delayed signal S 12 ' through its first input end d 11 , and receives the calibration path local oscillator signal through its second input end d 13 , and mixes the first delayed signal S 13 ' and the calibration path local oscillator signal to obtain the intermediate frequency signal Z.

[0125] Further, optionally, as shown in FIG. 6, each frequency-modulated optoelectronic circuit can further include an amplifier and / or an analog-to-digital conversion element. For example, the first frequency-modulated optoelectronic circuit 110 can further include an amplifier 118 and / or an analog-to-digital conversion element 119, and the second frequency-modulated optoelectronic circuit 210 can further include an amplifier 218 and / or an analog-to-digital conversion element 219. Still taking the first frequency-modulated optoelectronic circuit 110 as an example, when the amplifier 118 is included, the amplifier 118 can be connected between the light detection element 115 and the processing element 116, for signal amplification of the intermediate frequency signal Z detected by the light detection element 115. When the analog-to-digital conversion element 119 is included, the analog-to-digital conversion element 119 can be connected between the light detection element 115 and the processing element 116, for analog-to-digital conversion of the intermediate frequency signal Z detected by the light detection element 115 to obtain a digital signal. When both the amplifier 118 and the analog-to-digital conversion element 119 are included, the amplifier 118 and the analog-to-digital conversion element 119 can be connected in series between the light detection element 115 and the processing element 116. The amplifier 118 can amplify the intermediate frequency signal Z detected by the light detection element 115, and then input the amplified intermediate frequency signal Z to the analog-to-digital conversion element 119. The analog-to-digital conversion element 119 converts the amplified intermediate frequency signal Z into a digital signal, and inputs the digital signal to the processing element 116.

[0126] Further, optionally, as shown in FIG. 6, each frequency-modulated optoelectronic circuit can further include a target measurement path. For example, the first frequency-modulated optoelectronic circuit 110 can further include a target measurement path 113, and the second frequency-modulated optoelectronic circuit 210 can further include a target measurement path 213. Still taking the first frequency-modulated optoelectronic circuit 110 as an example, the first light splitting element 112 can further have a third output end (c 13 ), and the third output end c 13The first light splitting element 112 is connected to the target measurement path 113. The first light splitting element 112 splits the light signal S output by the light source 111 to obtain a first to-be-delayed signal S 11 , a calibration path local oscillator signal, and a probe signal, and outputs the first to-be-delayed signal S 11 through a first output end c 11 , outputs the calibration path local oscillator signal through a second output end c 12 , and outputs the probe signal through a third output end c 13 . Since the third output end c 13 is connected to the target measurement path 113, the probe signal can be received by the target measurement path 113, and the target measurement path 113 performs target measurement based on the received probe signal.

[0127] As an example, as shown in FIG. 7a, the target measurement path 113 can include a sixth light splitting element 1131, a fifth light transmission element 1132, a frequency mixer 1133, a light detection element 1134, an amplifier 1135, an analog-to-digital conversion element 1136, and a processing element 1137. The fifth light transmission element 1132 has a first end (b 51 ), a second end (b 52 ), and a third end (b 53 ), and the first end b 51 is unidirectionally transmitted to the second end b 52 , and the second end b 52 is unidirectionally transmitted to the third end b 53 . The input end of the sixth light splitting element 1131 is connected to the third output end c 13 of the first light splitting element 112, one output end of the sixth light splitting element 1131 is connected to the first end b 51 of the fifth light transmission element 1132, and the other output end is connected to one input end of the frequency mixer 1133. The second end b 52 of the fifth light transmission element 1132 is directed towards a probe space, and the third end b 53 of the fifth light transmission element 1132 is connected to the other input end of the frequency mixer 1133. The frequency mixer 1133, the light detection element 1134, the amplifier 1135, the analog-to-digital conversion element 1136, and the processing element 1137 are sequentially connected in series.

[0128] Based on the above structure and connection relationship, as shown in FIG. 7a, in the target measurement path 113, the sixth light splitting element 1131 can receive the probe signal output by the third output end c 13 of the first light splitting element 112, and split the probe signal to obtain a transmission signal and a target path local oscillator signal. The target path local oscillator signal is directly input to the frequency mixer 1133. The transmission signal is transmitted from the first end b 51Input, from the second end b of the fifth light transmission element 1132 52 Output, irradiated on the target in the detection space, and then reflected by the target back to the second end b of the fifth light transmission element 1132 52 and from the third end b of the fifth light transmission element 1132 53 to the mixer 1133 (referred to as a received signal or echo signal). The mixer 1133 mixes the target local oscillator signal input thereto and the received signal to obtain an intermediate frequency signal used for target measurement. The optical detection element 1134 detects the intermediate frequency signal, and inputs the detected intermediate frequency signal to the amplifier 1135. After the signal is amplified by the amplifier 1135, it is input to the analog-to-digital conversion element 1136. The analog-to-digital conversion element 1136 performs analog-to-digital conversion on the input intermediate frequency signal to obtain a digital signal, and inputs the digital signal to the processing element 1137. The processing element 1137 processes the input digital signal to obtain relevant information of the target.

[0129] For example, the processing element 1137 can perform fast Fourier transform (FFT) on the digital signal to extract distance information and motion state information of the target. The processing element 1137 can also analyze the time trend of the frequency difference of the digital signal to obtain the change of the target position in different time intervals, and further calculate the speed of the target. In addition, the processing element 1137 can output the distance, speed, etc. of the target object, and further convert it into position information in three-dimensional space, which can be used for subsequent scene modeling, obstacle recognition or other application requirements, etc.

[0130] It can be understood that the target measurement paths in the first frequency-modulated optoelectronic circuit and the second frequency-modulated optoelectronic circuit can be separate or shared. For example, FIG. 7a shows a scheme in which the two frequency-modulated optoelectronic circuits have different target measurement paths, and FIG. 7b shows a scheme in which the two frequency-modulated optoelectronic circuits share the same target measurement path 113. In the case of sharing, the sixth beam splitting element 1131 in the target measurement path 113 can be replaced by a beam combiner 1131 (or a combination of a beam combiner and a beam splitter, or other combinations of components, etc., without limitation). The beam combiner 1131 has two input ends and two output ends, one of which is connected to the third output end c of the first beam splitting element 112 in the first frequency-modulated optoelectronic circuit 110 13 , and the other is connected to the third output end i of the first beam splitting element 212 in the second frequency-modulated optoelectronic circuit 210 13 , one of the output ends is connected to the first end b of the fifth light transmission element 1132 51 , and the other is connected to one input end of the mixer 1133.

[0131] Based on the structure and connection relationship shown in FIG. 7b, the beam combiner 1131 can receive the probe signals obtained by the first beam splitter 112 in the first frequency-modulated optoelectronic circuit 110 and the probe signals obtained by the first beam splitter 212 in the second frequency-modulated optoelectronic circuit 210 through its two input ends. The beam combiner 1131 combines the two probe signals into one signal, and then splits the one signal into a transmission signal and a target local oscillator signal. The transmission signal is transmitted to the detection space to detect the target, and the target local oscillator signal is input to the frequency mixer 1133 to wait for mixing with the returned echo signal. In this way, by sharing one target measurement path, the probe signals obtained by splitting the light signals modulated by the two frequency-modulated optoelectronic circuits can be combined into one signal to measure the target together. This not only saves the number of target measurement paths that need to be set, saves the cost of components and occupied space, but also improves the power of the probe signal for measuring the target.

[0132] It should be noted that the optical delay element 300 shown in FIGS. 5a-7b is an example of a signal processing device having two frequency-modulated optoelectronic circuits, but the optical delay element 300 can also be extended to a signal processing device having three or more frequency-modulated optoelectronic circuits, so that the three or more frequency-modulated optoelectronic circuits share the first optical delay line 310 in the optical delay element 300. For example, based on the signal processing device shown in FIG. 6, please refer to FIGS. 8a-8c, which show the structure diagrams of three other possible signal processing devices provided by the first embodiment.

[0133] Case one, the signal processing device has a plurality of first frequency-modulated optoelectronic circuits.

[0134] In case one, please refer to FIG. 8a, the signal processing device can include N first frequency-modulated optoelectronic circuits, i.e., the first frequency-modulated optoelectronic circuit 110, the first frequency-modulated optoelectronic circuit 120, …, the first frequency-modulated optoelectronic circuit 1N0, N is an integer greater than or equal to 2. The structures of the N first frequency-modulated optoelectronic circuits 110-1N0 are the same, and the structure of each first frequency-modulated optoelectronic circuit can be referred to the above FIGS. 5a-7b.

[0135] For example, Figure 8a uses the structure shown in Figure 6 as an example. The first frequency-modulated photoelectric circuit 110 includes the light source 111, the first beam splitter 112, the optical delay element 300, the mixer 114, the photodetector 115, the amplifier 118, the analog-to-digital converter 119, the processing element 116, the drive circuit 117, and the target measurement path 113, as described above. Similarly, the first frequency-modulated photoelectric circuit 120 includes the light source 121, the first beam splitter 122, the optical delay element 300, the mixer 124, the photodetector 125, the amplifier 128, the analog-to-digital converter 129, the processing element 126, the drive circuit 127, and the target measurement path 123. ... The first frequency modulation optoelectronic circuit 1N0 includes a light source 1N1, a first beam splitter 1N2, an optical delay element 300, a mixer 1N4, a photodetector 1N5, an amplifier 1N8, an analog-to-digital converter 1N9, a processing element 1N6, a drive circuit 1N7, and a target measurement circuit 1N3.

[0136] In addition to the components mentioned above, as shown in Figure 8a, the signal processing device may also include a first beam combining element 410 and a second beam splitting element 520. The first beam combining element 410 has N input terminals, namely e1, e2, ..., e2. N The second beam splitter 520 has N output terminals, namely f1, f2, ..., f N The N input terminals e1 to e2 of the first optical combining element 410 N The first output terminals c of the N first beam splitting elements 112 to 1N2 of the N first frequency-modulated optoelectronic circuits 110 to 1N0 are connected in a one-to-one correspondence. 11 ~c N1 The second output terminal c of the N first beam splitting elements 112 to 1N2 of the N first frequency-modulated optoelectronic circuits 110 to 1N0 12 ~c N2 The third output terminal c of each of the N mixers 114 to 1N4 connected to the N first frequency modulation optoelectronic circuits 110 to 1N0, and the N first beam splitting elements 112 to 1N2 of the N first frequency modulation optoelectronic circuits 110 to 1N0 are respectively connected to one input terminal. 13 ~c N3 N target measurement paths 113 to 1N3 are respectively connected to N first frequency-modulated photoelectric circuits 110 to 1N0. An optical delay element 300 is connected between the output of the first beam combiner 410 and the input of the second beam splitter 520. For example, the output of the first beam combiner 410 is connected to the first end b of the first optical transmission element 321. 11 The third end b of the second optical transmission element 322 23 Connect the input terminal of the second beam splitter 520. The N output terminals f1 to f2 of the second beam splitter 520 are... NThe other input terminal of each of the N mixers 114 to 1N4, which are connected to the N first frequency modulation optoelectronic circuits 110 to 1N0, is also connected in a one-to-one correspondence.

[0137] Based on the above structure and connection relationships, in each first frequency-modulated photoelectric circuit, the first beam splitter performs beam splitting processing on the optical signal generated by the light source to obtain a detection signal, a calibration path local oscillator signal, and a signal to be delayed. The first beam splitter inputs the detection signal to the target measurement path for target measurement through its third output terminal, inputs the calibration path local oscillator signal to the mixer through its second output terminal, and inputs the signal to be delayed to the first beam combiner 410 through its first output terminal. The first beam combiner 410 inputs through its N input terminals e1 to e2... N Receives N delay signals S output from N first beam splitting elements 112 to 1N2 in N first frequency modulation optoelectronic circuits 110 to 1N0. 11 ~S 1N For N signals S to be delayed 11 ~S 1N The signal is combined to obtain the total signal to be delayed, and then input to the optical delay element 300. The optical delay element 300 delays the total signal to be delayed to obtain the total delayed signal, and then outputs the total delayed signal to the second beam splitter 520. The second beam splitter 520 splits the total delayed signal to obtain N delayed sub-signals S. 11 '~S 1N ', and through its N output terminals f1 to f N N delayed sub-signals S 11 '~S 1N The signals are respectively sent to N mixers 114 to 1N4 in N first frequency modulation photoelectric circuits 110 to 1N0. In each first frequency modulation photoelectric circuit, the mixer performs frequency mixing processing on the calibration path local oscillator signal input from the first beam splitter and the delayed sub-signal input from the second beam splitter 520 to obtain an intermediate frequency signal. The intermediate frequency signal is detected by the photodetector and converted into an electrical signal. The electrical signal is amplified by the amplifier and output to the analog-to-digital converter. After being converted into a digital signal by the analog-to-digital converter, it is output to the processing element. The processing element obtains a feedback signal based on the digital signal and inputs the feedback signal into the drive circuit. The drive circuit generates a modulation signal based on the feedback signal and inputs the modulation signal into the light source to calibrate the linearity between the modulation signal and the light signal output by the light source, so that the light source can output a light signal that conforms to the linear change law under the action of the modulation signal. After the light signal is split (i.e., the detection signal) and enters the target measurement path, the detection accuracy of the target measurement path can be improved.

[0138] With the structure shown in FIG. 8a, the to-be-delayed signals of the multiple first frequency-modulated optoelectronic circuits are transmitted in the same direction in the same optical delay line, and the to-be-delayed signal of the second frequency-modulated optoelectronic circuit is transmitted in the opposite direction in the optical delay line. Therefore, the multiple first frequency-modulated optoelectronic circuits and the second frequency-modulated optoelectronic circuit can share the same optical delay line for delay processing. In this way, the number of optical delay lines that need to be arranged in the signal processing device can be reduced, and the delay time of the multiple first frequency-modulated optoelectronic circuits and the second frequency-modulated optoelectronic circuit on the optical signal is not reduced, so that an extremely simple architecture and extremely low cost of the signal processing device can be achieved.

[0139] In case two, the signal processing device has multiple second frequency-modulated optoelectronic circuits.

[0140] In case two, referring to FIG. 8b, the signal processing device can include M second frequency-modulated optoelectronic circuits, i.e., a second frequency-modulated optoelectronic circuit 210, a second frequency-modulated optoelectronic circuit 220, …, and a second frequency-modulated optoelectronic circuit 2M0, where M is an integer greater than or equal to 2. The structures of the M second frequency-modulated optoelectronic circuits 210-2M0 are the same. The structure of each second frequency-modulated optoelectronic circuit can refer to the above-mentioned FIGS. 5a-7b.

[0141] For example, in FIG. 8b, the second frequency-modulated optoelectronic circuit 210 includes the light source 211, the first light splitting element 212, the optical delay element 300, the frequency mixer 214, the light detection element 215, the amplifier 218, the analog-to-digital conversion element 219, the processing element 216, the driving circuit 217, and the target measurement path 213, which are introduced above. Similarly, the second frequency-modulated optoelectronic circuit 220 includes the light source 221, the first light splitting element 222, the optical delay element 300, the frequency mixer 224, the light detection element 225, the amplifier 228, the analog-to-digital conversion element 229, the processing element 226, the driving circuit 227, and the target measurement path 223. … The second frequency-modulated optoelectronic circuit 2M0 includes the light source 2M1, the first light splitting element 2M2, the optical delay element 300, the frequency mixer 2M4, the light detection element 2M5, the amplifier 2M8, the analog-to-digital conversion element 2M9, the processing element 2M6, the driving circuit 2M7, and the target measurement path 2M3.

[0142] In addition to the above elements, as shown in FIG. 8b, the signal processing device can further include a second light combining element 420 and a third light splitting element 530. The second light combining element 420 has M input ends, i.e., g1, g2, …, gM, and the third light splitting element 530 has M output ends, i.e., h1, h2, …, hM. M N The M input ends g1-gM of the second light combining element 420 are connected one-to-one to the first output ends i1-iM of the M first light splitting elements 212-2M2 of the M second frequency-modulated optoelectronic circuits 210-2M0. M The M output ends h1-hM of the third light splitting element 530 are connected one-to-one to the second input ends j1-jM of the M second frequency-modulated optoelectronic circuits 210-2M0.​11 ~i M1 , M second frequency modulation photoelectric circuit 210 ~ 2M0 of M first light splitting element 212 ~ 2M2 of M input end i 12 ~i M2 respectively connected to M second frequency modulation photoelectric circuit 210 ~ 2M0 of M mixer 214 ~ 2M4 one input end, M second frequency modulation photoelectric circuit 210 ~ 2M0 of M first light splitting element 212 ~ 2M2 of third output end i 13 ~i M3 respectively connected to M second frequency modulation photoelectric circuit 210 ~ 2M0 of M target measurement path 213 ~ 2M3. Optical delay element 300 is connected between the output end of the second light combining element 420 and the input end of the third light splitting element 530, such as the output end of the second light combining element 420 is connected to the first end b 21 of the second light transmission element 322 13 connected to the input end of the third light splitting element 530. The M output end h1 ~ h M of the third light splitting element 530 is connected to the other input end of the M mixer 214 ~ 2M4 of the M second frequency modulation photoelectric circuit 210 ~ 2M0.

[0143] Based on the above structure and connection relationship, in each second frequency modulation photoelectric circuit, the first light splitting element performs light splitting processing on the light signal generated by the light source to obtain the detection signal, the calibration path local oscillator signal and the to-be-delayed signal, the detection signal is input to the target measurement path through the third output end for target measurement, the calibration path local oscillator signal is input to the mixer through the second output end, and the to-be-delayed signal is input to the second light combining element 420 through the first output end. The second light combining element 420 receives the M to-be-delayed signals S M output by the M first light splitting elements 212 ~ 2M2 in the M second frequency modulation photoelectric circuits 210 ~ 2M0 through its M input ends g1 ~ g 21 ~S 2M , performs beam combining processing on the M to-be-delayed signals S 21 ~S 2M to obtain the total to-be-delayed signal, and inputs the total to-be-delayed signal to the optical delay element 300. The optical delay element 300 performs delay processing on the total to-be-delayed signal to obtain the total delayed signal, and outputs the total delayed signal to the third light splitting element 530. The third light splitting element 530 performs light splitting processing on the total delayed signal to obtain M delayed sub-signals S 21 ' ~ S 2M ', and outputs the M delayed sub-signals S M ' ~ S 21 through its M output ends h1 ~ h 2MThe M second frequency modulation optoelectronic circuits 210-2M0 respectively send the M mixers 214-2M4. In each second frequency modulation optoelectronic circuit, the mixer mixes the calibration local oscillator signal input by the first light splitting element and the delayed sub-signal input by the third light splitting element 530 to obtain an intermediate frequency signal; the intermediate frequency signal is detected by the optical detection element and converted into an electrical signal, the electrical signal is amplified by the amplifier and output to the analog-to-digital conversion element, and after being converted into a digital signal by the analog-to-digital conversion element, the digital signal is output to the processing element; the processing element obtains a feedback signal according to the digital signal, and inputs the feedback signal into the drive circuit; the drive circuit generates a modulation signal according to the feedback signal, and inputs the modulation signal into the light source, so as to calibrate the linearity between the modulation signal and the optical signal output by the light source.

[0144] With the structure shown in FIG. 8b, the to-be-delayed signals of the plurality of second frequency modulation optoelectronic circuits are transmitted in the same optical delay line in the same direction, and the to-be-delayed signal of the first frequency modulation optoelectronic circuit is transmitted in the optical delay line in the opposite direction, so that the plurality of second frequency modulation optoelectronic circuits and the first frequency modulation optoelectronic circuit can share the same optical delay line for delay processing, thereby saving the number of optical delay lines that need to be arranged in the signal processing device, and without reducing the delay time of the plurality of second frequency modulation optoelectronic circuits and the first frequency modulation optoelectronic circuit to the optical signal, so that an extremely simple architecture and extremely low cost of the signal processing device can be achieved.

[0145] Case three, the signal processing device has a plurality of first frequency modulation optoelectronic circuits and a plurality of second frequency modulation optoelectronic circuits.

[0146] In case three, referring to FIG. 8c, the signal processing device can include the N first frequency modulation optoelectronic circuits 110-1N0 described in case one and the M second frequency modulation optoelectronic circuits 210-2M0 described in case two. Wherein, N and M are both integers greater than or equal to 2. The values of N and M can be the same or different, and are not limited in particular.

[0147] In order to realize multiplexing of the same first optical delay line 320, as shown in FIG. 8c, the signal processing device can further include the first light combining element 410 and the second light splitting element 520 introduced in the case one, and the second light combining element 420 and the third light splitting element 530 introduced in the case two. The first light combining element 410 and the second light splitting element 520 can realize that N first frequency-modulated optoelectronic circuits 110~1N0share the same first optical delay line 320, and the second light combining element 420 and the third light splitting element 530 can realize that M second frequency-modulated optoelectronic circuits 210~2M0share the same first optical delay line 320. Therefore, by using the structure shown in FIG. 8c, multiple first frequency-modulated optoelectronic circuits and multiple second frequency-modulated optoelectronic circuits can share the same optical delay line, so that the number of optical delay lines required to be arranged in the signal processing device can be further saved, and an extremely simple architecture and extremely low cost of the signal processing device can be realized.

[0148] It should be noted that the N first frequency-modulated optoelectronic circuits and one second frequency-modulated optoelectronic circuit in the case one, the M second frequency-modulated optoelectronic circuits and one first frequency-modulated optoelectronic circuit in the case two, and the N first frequency-modulated optoelectronic circuits and the M second frequency-modulated optoelectronic circuits in the case three are all introduced by taking an example of having a separate target measurement path. However, in combination with the design of sharing the target measurement path in the above-mentioned FIG. 7b, the N first frequency-modulated optoelectronic circuits and one second frequency-modulated optoelectronic circuit in the case one, or the M second frequency-modulated optoelectronic circuits and one first frequency-modulated optoelectronic circuit in the case two, or the N first frequency-modulated optoelectronic circuits and the M second frequency-modulated optoelectronic circuits in the case three can also share the same target measurement path, or some of the frequency-modulated optoelectronic circuits can share the same target measurement path, and other frequency-modulated optoelectronic circuits have a separate target measurement path, etc., which are not limited in the present application.

[0149] In addition, in the above case one to case three, for the co-directional transmission of the plurality of first frequency-modulated optoelectronic circuits or the plurality of second frequency-modulated optoelectronic circuits, the corresponding plurality of to-be-delayed signals needs to be combined into one path and then divided into multiple paths, therefore, to realize the accuracy of beam splitting, the plurality of to-be-delayed signals needs to have a difference in wavelength. For example, in the above case one or case three, the N light signals output by the N light sources in the N first frequency-modulated optoelectronic circuits can be light signals of different wavelengths, after these light signals of different wavelengths are split by the N first light splitting elements into to-be-delayed signals of different wavelengths, the to-be-delayed signals of different wavelengths are combined into a multi-wavelength light signal by the first light combining element 410, the multi-wavelength light signal is subjected to delay processing by the optical delay element 300, and then the multi-wavelength light signal is split into N delayed light signals by the second light splitting element 520, and the N delayed light signals enter the respective mixers and are mixed with the calibration local oscillator signals of the corresponding wavelengths. For another example, in the above case two or case three, the M light signals output by the M light sources in the M second frequency-modulated optoelectronic circuits can be light signals of different wavelengths, after these light signals of different wavelengths are split by the M first light splitting elements into to-be-delayed signals of different wavelengths, the to-be-delayed signals of different wavelengths are combined into a multi-wavelength light signal by the second light combining element 420, the multi-wavelength light signal is subjected to delay processing by the optical delay element 300, and then the multi-wavelength light signal is split into M delayed light signals by the third light splitting element 530, and the M delayed light signals enter the respective mixers and are mixed with the calibration local oscillator signals of the corresponding wavelengths.

[0150] The second light splitting element 520 or the third light splitting element 530 can be based on wavelength splitting, power splitting, or resonance splitting, and the specific implementation is not limited. For example, when based on wavelength splitting, the second light splitting element 520 or the third light splitting element 530 can split the delayed light signals of different wavelengths, and the delayed light signals of different wavelengths are output to the respective mixers and are mixed with the calibration local oscillator signals of the same wavelength. When based on power splitting or resonance splitting, although the second light splitting element 520 or the third light splitting element 530 can split the delayed light signals of multiple wavelengths in each path (for example, the delayed light signal in each path is a mixed light signal of each wavelength), when mixed in the mixer, the wavelength of the calibration local oscillator signal is used to mix the wavelength of the delayed light signal, and other wavelengths are not used, therefore, based on power splitting or resonance splitting, the subsequent mixing function and processing function can also be realized.

[0151] In addition, based on the interference characteristics and independence of light, the plurality of to-be-delayed signals corresponding to the first frequency-modulated optoelectronic circuit and the second frequency-modulated optoelectronic circuit for reverse transmission can be signals of the same wavelength or signals of different wavelengths, without limitation. For example, in combination with the third case described above, the N light sources of the N first frequency-modulated optoelectronic circuits can emit N first light signals of different wavelengths, and the M light sources of the M second frequency-modulated optoelectronic circuits can emit M second light signals of different wavelengths. The N first light signals and the M second light signals can be completely the same in wavelength, completely different in wavelength, or have one or more wavelengths that are the same and the other wavelengths that are different, without limitation.

[0152] Embodiment Two

[0153] In the second embodiment, a four-port optical transmission element can be arranged on the side of the first end a1 and / or the second end a2 of the first optical delay line 310 to control the transmission direction of the signal.

[0154] For example, referring to FIG. 9, a structural schematic diagram of a possible signal processing device provided by the second embodiment is shown. In this example, in addition to the first optical delay line 310 described above, the optical delay element 300 can further include a third optical transmission element 330 and a fourth optical transmission element 340. The third optical transmission element 330 has a first end (b1), a second end (b2), a third end (b3), and a fourth end (b4), and the first end b1 to the second end b2, the second end b2 to the third end b3, the third end b3 to the fourth end b4 are unidirectional transmission. The fourth optical transmission element 340 has a first end (b5), a second end (b6), a third end (b7), and a fourth end (b8), and the first end b5 to the second end b6, the second end b6 to the third end b7, the third end b7 to the fourth end b8 are unidirectional transmission. The first end b1 of the third optical transmission element 330 is connected to the first light splitting element 112 in the first frequency-modulated optoelectronic circuit 110, the second end b2 of the third optical transmission element 330 is connected to the first end a1 of the first optical delay line 310, the third end b3 of the third optical transmission element 330 is connected to the second end a2 of the first optical delay line 310, and the fourth end b4 of the third optical transmission element 330 is connected to the second light splitting element 122 in the second frequency-modulated optoelectronic circuit 120. The first end b5 of the fourth optical transmission element 340 is connected to the third light splitting element 132 in the first frequency-modulated optoelectronic circuit 110, the second end b6 of the fourth optical transmission element 340 is connected to the third end b3 of the third optical transmission element 330, the third end b7 of the fourth optical transmission element 340 is connected to the fourth light splitting element 142 in the second frequency-modulated optoelectronic circuit 120, and the fourth end b8 of the fourth optical transmission element 340 is connected to the fourth end b4 of the third optical transmission element 330. 31 32 33 34 31 32 32 33 33 34 41 42 43 44 41 42 42 43 43 44 31 32 33 ​​​​​​​​​​​​​​​​​​​​​​The third end b of the fourth optical transmission element 340 43 The fourth end b of the third optical transmission element 330 34 The mixer 114 is connected to the first frequency modulation optoelectronic circuit 110. The first terminal b of the fourth optical transmission element 340... 41 The second end b of the first beam splitter 212 and the fourth optical transmission element 340 in the second frequency modulation optoelectronic circuit 210 are connected. 42 Connect the second end a2 of the first optical delay line 310 to the fourth end b of the fourth optical transmission element 340. 44 The mixer 214 is connected to the second frequency modulation optoelectronic circuit 210.

[0155] Based on the above structure and connection relationship, as shown in Figure 9, in the first frequency modulation photoelectric circuit 110, the first signal S to be delayed after being split by the first beam splitting element 112 is... 11 It will enter the first end b of the third optical transmission element 330 31 Because of the first end b 31 To the second end b 32 It is a unidirectional transmission; therefore, the first delay signal S... 11 It will be from the second end b of the third optical transmission element 330 32 The signal is output to the first optical delay line 310 for delay processing. After this delay processing by the first optical delay line 310, the first delayed signal S... 11 It will enter the second end b of the fourth optical transmission element 340 42 Because of the second end b 42 To the third end b 43 It is a unidirectional transmission; therefore, after the first delay, signal S... 11 'It will come from the third end b of the fourth optical transmission element 340' 43 Output to the third terminal b of the third optical transmission element 330 33 Because of the third end b 33 To the fourth end b 34 It is a unidirectional transmission; therefore, after the first delay, signal S... 11 It will come from the fourth end b of the third optical transmission element 330 34 The output is sent to mixer 114 to participate in the mixing operation.

[0156] In the second frequency-modulated photoelectric circuit 210, the second delay signal S after being split by the first beam splitter 212 21 It will enter the first end b of the fourth optical transmission element 340 41 Because of the first end b 41 To the second end b 42 It is a unidirectional transmission; therefore, the second delay signal S... 21 It will be from the second end b of the fourth optical transmission element 340 42The second delayed signal S2 is output to the first optical delay line 310 and is subjected to delay processing. After the delay processing by the first optical delay line 310, the second delayed signal S2 is output to the second end b2 of the third optical transmission element 330. 21 The second delayed signal S2 is output to the first optical delay line 310 and is subjected to delay processing. After the delay processing by the first optical delay line 310, the second delayed signal S2 is output to the second end b2 of the third optical transmission element 330. 32 Since the second end b2 is unidirectionally connected to the third end b3, the second delayed signal S2 is output from the third end b3 of the third optical transmission element 330. 32 to the fourth end b4, the second delayed signal S2 is output from the fourth end b4 of the fourth optical transmission element 340. 33 Since the second end b2 is unidirectionally connected to the third end b3, the second delayed signal S2 is output from the third end b3 of the third optical transmission element 330. 21 to the fourth end b4, the second delayed signal S2 is output from the fourth end b4 of the fourth optical transmission element 340. 33 Since the second end b2 is unidirectionally connected to the third end b3, the second delayed signal S2 is output from the third end b3 of the third optical transmission element 330. 43 to the fourth end b4, the second delayed signal S2 is output from the fourth end b4 of the fourth optical transmission element 340. 43 Since the second end b2 is unidirectionally connected to the third end b3, the second delayed signal S2 is output from the third end b3 of the third optical transmission element 330. 44 to the fourth end b4, the second delayed signal S2 is output from the fourth end b4 of the fourth optical transmission element 340. 21 Since the second end b2 is unidirectionally connected to the third end b3, the second delayed signal S2 is output from the third end b3 of the third optical transmission element 330. 44 Since the second end b2 is unidirectionally connected to the third end b3, the second delayed signal S2 is output from the third end b3 of the third optical transmission element 330.

[0157] The third optical transmission element 330 or the fourth optical transmission element 340 can be a four-port element or can be composed of two-port elements, three-port elements, etc. For example, referring to FIGS. 10a to 10c, specific structural diagrams of three signal processing apparatuses according to Embodiment 2 are shown, and the three signal processing apparatuses can be provided in the following provision modes.

[0158] Provision Mode 1

[0159] In the provision mode 1, as shown in FIG. 10a, the third optical transmission element 330 can include a first sub optical transmission element 331 and a second sub optical transmission element 332. The first sub optical transmission element 331 has a first end (j1), a second end (j2), and a third end (j3), and the first end j1 is unidirectionally connected to the second end j2, and the second end j2 is unidirectionally connected to the third end j3. The second sub optical transmission element 332 has a first end (j4), a second end (j5), and a third end (j6), and the first end j4 is unidirectionally connected to the second end j5, and the second end j5 is unidirectionally connected to the third end j6. The first end j1 of the first sub optical transmission element 331 is the first end b1 of the third optical transmission element 330, and the third end j3 of the first sub optical transmission element 331 is the second end b2 of the third optical transmission element 330. 11 12 13 11 12 12 13 21 22 23 21 22 22 23 11 31 ​​​​​​​​​​​​​​​, that is, connecting the first light splitting element 112 in the first frequency modulation optoelectronic circuit 110, the second end j of the first sub light transmission element 331 12 connecting the first end j of the second sub light transmission element 332 21 , the third end j of the first sub light transmission element 331 13 the fourth end b of the third light transmission element 330 34 , that is, connecting the second end j of the second sub light transmission element 332, the second end j of the first light delay line 310 22 the second end b of the third light transmission element 330 32 , that is, connecting the first end a1 of the first light delay line 310, the third end j of the second sub light transmission element 332 23 the third end b of the third light transmission element 330 33 , that is, connecting the third end b of the fourth light transmission element 43 .

[0160] Based on the above structure and connection relationship, as shown in FIG. 10a, in the first frequency modulation optoelectronic circuit 110, the first to-be-delayed signal S 11 after being split by the first light splitting element 112 enters the first light delay line 310 for delay processing after sequentially passing through the first end j of the first sub light transmission element 331 11 , the second end j of the first sub light transmission element 331 12 , the first end j of the second sub light transmission element 332 21 , the second end j of the second sub light transmission element 332 22 . The first delayed signal S 11 ' after delay processing by the first light delay line 310 enters the frequency mixer 114 for frequency mixing operation after sequentially passing through the second end b of the fourth light transmission element 340 42 , the third end b of the fourth light transmission element 340 43 , the third end j of the second sub light transmission element 332 23 , the first end j of the second sub light transmission element 332 21 , the second end j of the first sub light transmission element 331 12 , the third end j of the first sub light transmission element 331 13 . In this way, the one-way transmission function of the third light transmission element 330 can be realized through the two three-port first sub light transmission element 331 and second sub light transmission element 332.

[0161] Setting mode two

[0162] In the second setting mode, as shown in FIG. 10b, the fourth light transmission element 340 can include a third sub light transmission element 341 and a fourth sub light transmission element 342. The third sub light transmission element 341 has a first end (j 31 ), a second end (j 32 ) and a third end (j 33 ). The transmission from the first end j 31 to the second end j 32 and the transmission from the second end j 32 to the third end j 33 are unidirectional. The fourth sub light transmission element 342 has a first end (j 41 ), a second end (j 42 ) and a third end (j 43 ). The transmission from the first end j 41 to the second end j 42 and the transmission from the second end j 42 to the third end j 43 are unidirectional. The first end j 31 of the third sub light transmission element 341 is the first end b 41 of the fourth light transmission element 340, i.e., connected to the first light splitting element 212 in the second frequency modulation optoelectronic circuit 210. The second end j 22 of the third sub light transmission element 341 is connected to the first end j 41 of the fourth sub light transmission element 342. The third end j 33 of the third sub light transmission element 341 is the fourth end b 44 of the fourth light transmission element 340, i.e., connected to the frequency mixer 214 in the second frequency modulation optoelectronic circuit 210. The second end j 42 of the fourth sub light transmission element 342 is the second end b 42 of the fourth light transmission element 340, i.e., connected to the second end a2 of the first light delay line 310. The third end j 43 of the fourth sub light transmission element 342 is the third end b 43 of the fourth light transmission element 340, i.e., connected to the third end b 33 of the third light transmission element.

[0163] Based on the above structure and connection, as shown in FIG. 10b, in the second frequency modulation optoelectronic circuit 210, the second to-be-delayed signal S 21 split by the first light splitting element 212 passes through the first end j 31 of the third sub light transmission element 341, the second end j 32 of the third sub light transmission element 341, the first end j 41 of the fourth sub light transmission element 342 and the second end j 42 of the fourth sub light transmission element 342 in sequence.The second delayed post-signal S 21 the second end j of the second sub-optical transmission element 332 22 the third end j of the second sub-optical transmission element 332 23 the third end j of the fourth sub-optical transmission element 342 43 the first end j of the fourth sub-optical transmission element 342 41 the second end j of the third sub-optical transmission element 341 32 the third end j of the third sub-optical transmission element 341 33 the third end j of the fourth sub-optical transmission element 342

[0164] Setting Mode Three

[0165] In the setting mode three, as shown in FIG. 10c, the third optical transmission element 330 can include the first sub-optical transmission element 331 and the second sub-optical transmission element 332 introduced in the setting mode four, and the fourth optical transmission element 340 can include the third sub-optical transmission element 341 and the fourth sub-optical transmission element 342 introduced in the setting mode five.

[0166] Based on the structure and connection relationship, as shown in FIG. 10c, in the first frequency-modulated optoelectronic circuit 110, the first delayed post-signal S 11 the second end j of the fourth sub-optical transmission element 342 42 the third end j of the fourth sub-optical transmission element 342 43 the third end j of the second sub-optical transmission element 332 23 the first end j of the second sub-optical transmission element 332 21 the second end j of the first sub-optical transmission element 331 12 the third end j of the first sub-optical transmission element 331 13 the third end j of the fourth sub-optical transmission element 342 21 the second end j of the second sub-optical transmission element 332 22 the third end j of the second sub-optical transmission element 332 23 the third end j of the fourth sub-optical transmission element 342 43 the first end j of the fourth sub-optical transmission element 342 41 the second end j of the third sub-optical transmission element 341 32The third terminal j of the third sub-optical transmission element 341 33 The signal then enters mixer 214 and participates in the mixing operation. Thus, through the first sub-optical transmission element 331, the second sub-optical transmission element 332, the third sub-optical transmission element 341, and the fourth sub-optical transmission element 342, the signals to be delayed in the first frequency-modulated optoelectronic circuit 110 and the second frequency-modulated optoelectronic circuit 210 can be transmitted in reverse on the same first optical delay line 310. Therefore, the first frequency-modulated optoelectronic circuit 110 and the second frequency-modulated optoelectronic circuit 210 can share the same first optical delay line 310 to achieve signal delay.

[0167] Optionally, taking the structure shown in Figure 10c above as an example, please refer to Figure 11, which shows a schematic diagram of another signal processing device provided in Embodiment 2. In this example, in addition to the first optical delay line 310, the third optical transmission element 330, and the fourth optical transmission element 340 described above, the optical delay element 300 may also include a second optical delay line 350, which is disposed at the third end b of the third optical transmission element 330. 33 and the third end b of the fourth optical transmission element 340 43 On the connection line between them, that is, on the third end j of the second sub-optical transmission element 332 23 With the third terminal j of the fourth sub-optical transmission element 342 43 On the connection line between them. For example, the second optical delay line 350 includes a first end (a3) ​​and a second end (a4), and the first end a3 is connected to the third end j of the second sub-optical transmission element 332. 23 The second end a4 is connected to the third end j of the fourth sub-optical transmission element 342. 43 .

[0168] Based on the above structure and connection relationship, as shown in Figure 11, in the first frequency modulation photoelectric circuit 110, the first signal to be delayed S 11 After the initial delay by the first optical delay line 310, from the second end j of the fourth sub-optical transmission element 342 42 Entering from the third end j of the fourth sub-optical transmission element 342 43 The output signal enters the second optical delay line 350 and is further delayed by the second optical delay line 350. The signal after this second delay then passes sequentially through the third terminal j of the second sub-optical transmission element 332. 23 The first end j of the second sub-optical transmission element 332 21 The second end j of the first sub-optical transmission element 331 12 and the third terminal j of the first sub-optical transmission element 331 13 Then, it enters mixer 114 and participates in the mixing operation. Similarly, in the second frequency modulation photoelectric circuit 210, the second delay signal S 21After the first time delay by the first optical delay line 310, the signal enters the second end j 22 of the second sub-optical transmission element 332, and then enters the third end j 23 of the second sub-optical transmission element 332, and then enters the second optical delay line 350, and is delayed again by the second optical delay line 350. The signal after the second time delay enters the third end j 43 of the fourth sub-optical transmission element 342, the first end j 41 of the fourth sub-optical transmission element 342, the second end j 32 of the third sub-optical transmission element 341, and the third end j 33 of the third sub-optical transmission element 341, and then enters the mixer 214 to participate in the mixing operation.

[0169] It should be noted that the optical delay element 300 in the structure shown in FIG. 11 has two optical delay lines, while the optical delay element 300 in the structure shown in FIG. 10c has only one optical delay line. On the basis of the same time delay, the total length of the two optical delay lines in FIG. 11 is equal to the length of the optical delay line in FIG. 10c. That is to say, the optical delay line in FIG. 10c can be divided into two parts, one part is placed on the line between the second end j 22 of the second sub-optical transmission element 332 and the second end j 42 of the fourth sub-optical transmission element 342, and the other part is placed on the line between the third end j 23 of the second sub-optical transmission element 332 and the third end j 43 of the fourth sub-optical transmission element 342, thereby obtaining the structure shown in FIG. 11. In another aspect, if the length of each optical delay line is the same, the total length of the two optical delay lines in FIG. 11 is equal to twice the length of the optical delay line in FIG. 10c. Therefore, the time delay of the optical delay element 300 in FIG. 11 is twice that of the optical delay element 300 in FIG. 10c.

[0170] The related content in the above-mentioned embodiment one also applies to the embodiment two. For example, based on the structure shown in FIG. 6 in the embodiment one, the structure shown in FIG. 11 is improved to obtain the structure shown in FIG. 12. In this example, in each frequency-modulated optoelectronic circuit, the first light splitting element can include three output ends, one output end is connected to the target measurement path, one output end is connected to the optical delay element 300, and one output end is connected to the mixer. For example, taking the second frequency-modulated optoelectronic circuit 210 as an example, the first light splitting element 212 includes a first output end i 11 , a second output end i 12 , and a third output end i 13 , the first output end i 11 is connected to the first end j 31 of the third sub-optical transmission element 341, the second output end i 12one input of the mixer 214, the third output i 13 The target measurement path 213 is connected. The first light splitting element 212 splits the light signal output by the light source 211 to obtain a detection signal, a calibration path local oscillator signal and a to-be-delayed signal, and outputs the detection signal to the target measurement path 213 through the second output i 13 The detection signal is output to the target measurement path 213 for target identification, and the calibration path local oscillator signal is output to the mixer 214 through the first output i 12 The detection signal is output to the target measurement path 213 for target identification, and the calibration path local oscillator signal is output to the mixer 214 through the first output i 11 The to-be-delayed signal is output to the optical delay element 300 for delay processing, and the signal after delay processing is input to the mixer 214. The mixer 214 mixes and processes the calibration path local oscillator signal and the signal after delay processing to obtain an intermediate frequency signal.

[0171] In addition, the optical delay element 300 shown in FIGS. 9 to 12 is only an example of a signal processing device including two frequency modulation optoelectronic circuits, but the optical delay element 300 can also be extended to a signal processing device having three or more frequency modulation optoelectronic circuits, so that the three or more frequency modulation optoelectronic circuits share the first optical delay line 310 in the optical delay element 300, or share the first optical delay line 310 and the second optical delay line 350.

[0172] For example, please refer to FIGS. 13a to 13c, which show the structure diagrams of three other possible signal processing devices provided by the second embodiment.

[0173] In the first case, the signal processing device has a plurality of first frequency modulation optoelectronic circuits.

[0174] In the first case, please refer to FIG. 13a, the signal processing device can include N first frequency modulation optoelectronic circuits, i.e., a first frequency modulation optoelectronic circuit 110, a first frequency modulation optoelectronic circuit 120, …, a first frequency modulation optoelectronic circuit 1N0, N is an integer greater than or equal to 2. The structures of the N first frequency modulation optoelectronic circuits 110-1N0 are the same, and the structure of each first frequency modulation optoelectronic circuit can refer to the above-mentioned FIGS. 9 to 12.

[0175] For example, Figure 13a uses the structure shown in Figure 12 as an example. The first frequency-modulated photoelectric circuit 110 includes the light source 111, the first beam splitter 112, the optical delay element 300, the mixer 114, the photodetector 115, the amplifier 118, the analog-to-digital converter 119, the processing element 116, the drive circuit 117, and the target measurement path 113, as described above. Similarly, the first frequency-modulated photoelectric circuit 120 includes the light source 121, the first beam splitter 122, the optical delay element 300, the mixer 124, the photodetector 125, the amplifier 128, the analog-to-digital converter 129, the processing element 126, the drive circuit 127, and the target measurement path 123. ... The first frequency modulation optoelectronic circuit 1N0 includes a light source 1N1, a first beam splitter 1N2, an optical delay element 300, a mixer 1N4, a photodetector 1N5, an amplifier 1N8, an analog-to-digital converter 1N9, a processing element 1N6, a drive circuit 1N7, and a target measurement circuit 1N3.

[0176] In addition to the components mentioned above, as shown in Figure 13a, the signal processing device may also include a third beam combining element 430 and a fourth beam splitting element 540. The third beam combining element 430 has N input terminals, namely k1, k2, ..., k N The fourth beam splitter 540 has N output terminals, namely q1, q2, ..., q... N The N input terminals k1 to k2 of the third optical combining element 430 N The first output terminals c of the N first beam splitting elements 112 to 1N2 of the N first frequency-modulated optoelectronic circuits 110 to 1N0 are connected in a one-to-one correspondence. 11 ~c N1 The second output terminal c of the N first beam splitting elements 112 to 1N2 of the N first frequency-modulated optoelectronic circuits 110 to 1N0 12 ~c N2 The third output terminal c of each of the N mixers 114 to 1N4 connected to the N first frequency modulation optoelectronic circuits 110 to 1N0, and the N first beam splitting elements 112 to 1N2 of the N first frequency modulation optoelectronic circuits 110 to 1N0 are respectively connected to one input terminal. 13 ~c N3 N target measurement paths 113 to 1N3 are respectively connected to N first frequency-modulated photoelectric circuits 110 to 1N0. An optical delay element 300 is connected between the output of the third beam combiner 430 and the input of the fourth beam splitter 540. For example, the output of the third beam combiner 430 is connected to the first terminal of the first sub-optical transmission element 331. 11 (i.e., the first end b of the third optical transmission element) 31 The third terminal j of the first sub-optical transmission element 331 13 (i.e., the fourth end b of the third optical transmission element) 34Connect the input terminal of the fourth beam splitter 540. The N output terminals q1~q2 of the fourth beam splitter 540 are... N The other input terminal of each of the N mixers 114 to 1N4, which are connected to the N first frequency modulation optoelectronic circuits 110 to 1N0, is also connected in a one-to-one correspondence.

[0177] Based on the above structure and connection relationships, in each first frequency-modulated photoelectric circuit, the first beam splitter performs beam splitting processing on the optical signal generated by the light source to obtain a detection signal, a calibration path local oscillator signal, and a signal to be delayed. The first beam splitter inputs the detection signal to the target measurement path for target measurement through its third output terminal, inputs the calibration path local oscillator signal to the mixer through its second output terminal, and inputs the signal to be delayed to the third beam combiner 430 through its first output terminal. The third beam combiner 430 inputs through its N input terminals k1 to k2. N Receives N delay signals S output from N first beam splitting elements 112 to 1N2 in N first frequency modulation optoelectronic circuits 110 to 1N0. 11 ~S 1N For N signals S to be delayed 11 ~S 1N The signal is combined to obtain the total signal to be delayed, and then input to the first sub-optical transmission element 331. The total signal to be delayed passes sequentially through the first sub-optical transmission element 331 and the second sub-optical transmission element 332 before being transmitted to the first optical delay line 310 for initial delay. It then passes through the fourth sub-optical transmission element 342 and enters the second optical delay line 350 for secondary delay. After passing through the second sub-optical transmission element 332 and the first sub-optical transmission element 331, it enters the fourth beam splitter 540. The fourth beam splitter 540 splits the total delayed signal to obtain N delayed sub-signals S. 11 '~S 1N ', and through its N output terminals q1~q N N delayed sub-signals S 11 '~S 1N The signals are respectively sent to N mixers 114 to 1N4 in N first frequency modulation photoelectric circuits 110 to 1N0. In each first frequency modulation photoelectric circuit, the mixer performs frequency mixing processing on the calibration path local oscillator signal input from the first beam splitter and the delayed sub-signal input from the fourth beam splitter 540 to obtain an intermediate frequency signal. The intermediate frequency signal is detected by the photodetector and converted into an electrical signal. The electrical signal is amplified by the amplifier and output to the analog-to-digital converter. After being converted into a digital signal by the analog-to-digital converter, it is output to the processing element. The processing element obtains a feedback signal based on the digital signal and inputs the feedback signal into the drive circuit. The drive circuit generates a modulation signal based on the feedback signal and inputs the modulation signal into the light source to calibrate the linearity between the modulation signal and the light signal output by the light source.

[0178] With the structure shown in Fig. 13a, the to-be-delayed signals of the multiple first frequency-modulated optoelectronic circuits are combined into one signal and then transmitted in the same direction in the same two optical delay lines, and the to-be-delayed signal of the second frequency-modulated optoelectronic circuit is transmitted in the opposite direction in the two optical delay lines. Therefore, the multiple first frequency-modulated optoelectronic circuits and the second frequency-modulated optoelectronic circuit can share the same two optical delay lines, which can save the length of the optical delay lines that need to be arranged in the signal processing device, and does not reduce the delay time of the optical signal of the multiple first frequency-modulated optoelectronic circuits and the second frequency-modulated optoelectronic circuit, thereby achieving an extremely simple architecture and extremely low cost of the signal processing device.

[0179] In case two, the signal processing device has multiple second frequency-modulated optoelectronic circuits.

[0180] In case two, referring to Fig. 13b, the signal processing device can include M second frequency-modulated optoelectronic circuits, i.e., a second frequency-modulated optoelectronic circuit 210, a second frequency-modulated optoelectronic circuit 220, …, and a second frequency-modulated optoelectronic circuit 2M0, where M is an integer greater than or equal to 2. The structures of the M second frequency-modulated optoelectronic circuits 210-2M0 are the same, and the structure of each second frequency-modulated optoelectronic circuit can refer to the above-mentioned Figs. 9-12.

[0181] For example, in Fig. 13b, the second frequency-modulated optoelectronic circuit 210 includes the light source 211, the first light splitting element 212, the optical delay element 300, the frequency mixer 214, the light detection element 215, the amplifier 218, the analog-to-digital conversion element 219, the processing element 216, the driving circuit 217, and the target measurement path 213, which are introduced above. Similarly, the second frequency-modulated optoelectronic circuit 220 includes the light source 221, the first light splitting element 222, the optical delay element 300, the frequency mixer 224, the light detection element 225, the amplifier 228, the analog-to-digital conversion element 229, the processing element 226, the driving circuit 227, and the target measurement path 223. … The second frequency-modulated optoelectronic circuit 2M0 includes the light source 2M1, the first light splitting element 2M2, the optical delay element 300, the frequency mixer 2M4, the light detection element 2M5, the amplifier 2M8, the analog-to-digital conversion element 2M9, the processing element 2M6, the driving circuit 2M7, and the target measurement path 2M3.

[0182] In addition to the above elements, as shown in Fig. 13b, the signal processing device can further include a fourth light combining element 440 and a fifth light splitting element 550. The fourth light combining element 440 has M input ends, i.e., p1, p2, …, and pM, and the fifth light splitting element 550 has M output ends, i.e., r1, r2, …, and rM. M M The M input ends p1-pM of the fourth light combining element 440 are connected to the M output ends of the M second frequency-modulated optoelectronic circuits 210-2M0, respectively. M ​The first output terminals i of the M first beam splitting elements 212 to 2M2 of the M second frequency-modulated photoelectric circuits 210 to 2M0 are connected in a one-to-one correspondence. 11 ~i M1 The second output terminal i of the M first beam splitting elements 212 to 2M2 of the M second frequency-modulated optoelectronic circuits 210 to 2M0 12 ~i M2 The third output terminal i of each of the M mixers 214 to 2M4 connected to the M second frequency modulation optoelectronic circuits 210 to 2M0, and the M first beam splitting elements 212 to 2M2 of the M second frequency modulation optoelectronic circuits 210 to 2M0 are respectively connected to one input terminal. 13 ~i M3 M target measurement paths 213 to 2M3 are respectively connected to M second frequency-modulated photoelectric circuits 210 to 2M0. An optical delay element 300 is connected between the output of the fourth beam combiner 440 and the input of the fifth beam splitter 550. For example, the output of the fourth beam combiner 440 is connected to the first terminal of the third sub-optical transmission element 341. 31 (i.e., the first end b of the fourth optical transmission element 340) 41 The third terminal j of the third sub-optical transmission element 341 33 (i.e., the fourth end b of the fourth optical transmission element 340) 44 Connect the input terminal of the fifth beam splitter 550. The M output terminals r1~r2 of the fifth beam splitter 550 are... M The other input terminal of each of the M mixers 214 to 2M4 of the M second frequency modulation optoelectronic circuits 210 to 2M0 is connected in a one-to-one correspondence.

[0183] Based on the above structure and connection relationships, in each second frequency-modulated photoelectric circuit, the first beam splitter processes the optical signal generated by the light source to obtain a detection signal, a calibration path local oscillator signal, and a signal to be delayed. The detection signal is input to the target measurement path for target measurement through its third output terminal, the calibration path local oscillator signal is input to the mixer through its second output terminal, and the signal to be delayed is input to the fourth beam combiner 440 through its first output terminal. M Receives M delay signals S output from M first beam splitting elements 212 to 2M2 in M ​​second frequency-modulated optoelectronic circuits 210 to 2M0. 21 ~S 2M For M signals S to be delayed 21 ~S 2MThe signal is combined to obtain the total signal to be delayed, and then input to the fourth sub-optical transmission element 342. The total signal to be delayed passes sequentially through the third sub-optical transmission element 341 and the fourth sub-optical transmission element 342 before entering the first optical delay line 310 for initial delay. It then passes through the second sub-optical transmission element 332 before entering the second optical delay line 350 for secondary delay. Finally, it passes through the fourth sub-optical transmission element 342 and the third sub-optical transmission element 341 before entering the fifth beam splitter 550. The fifth beam splitter 550 splits the total delayed signal to obtain M delayed sub-signals S. 21 '~S 2M ', and through its M output terminals r1~r M M delayed sub-signals S 21 '~S 2M The signals are respectively sent to M mixers 214 to 2M4 in M ​​second frequency-modulated photoelectric circuits 210 to 2M0. In each second frequency-modulated photoelectric circuit, the mixer performs frequency mixing processing on the calibration path local oscillator signal input from the first beam splitter and the delayed sub-signal input from the fifth beam splitter 550 to obtain an intermediate frequency signal. The intermediate frequency signal is detected by the photodetector and converted into an electrical signal. This electrical signal is amplified by the amplifier and output to the analog-to-digital converter. After being converted into a digital signal by the analog-to-digital converter, it is output to the processing element. The processing element obtains a feedback signal based on the digital signal and inputs the feedback signal into the drive circuit. The drive circuit generates a modulation signal based on the feedback signal and inputs the modulation signal into the light source to calibrate the linearity between the modulation signal and the light signal output by the light source.

[0184] Using the structure shown in Figure 13b, the signals to be delayed in multiple second frequency-modulated photoelectric circuits are transmitted in the same direction in the same two optical delay lines, while the signals to be delayed in the first frequency-modulated photoelectric circuit are transmitted in opposite directions in these two optical delay lines. Therefore, multiple second frequency-modulated photoelectric circuits and one first frequency-modulated photoelectric circuit can reuse the same two optical delay lines, which can save the length of the optical delay lines that need to be set in the signal processing device, without reducing the delay time of the optical signal by multiple second frequency-modulated photoelectric circuits and one first frequency-modulated photoelectric circuit. This enables a simplified architecture and extremely low cost for the signal processing device.

[0185] Scenario 3: The signal processing device has multiple first frequency modulation optoelectronic circuits and multiple second frequency modulation optoelectronic circuits.

[0186] In scenario three, referring to Figure 13c, the signal processing device may include N first frequency-modulated photoelectric circuits 110 to 1N0 as described in scenario one, and M second frequency-modulated photoelectric circuits 210 to 2M0 as described in scenario two. Here, N and M are both integers greater than or equal to 2. The values ​​of N and M can be the same or different, and there is no specific limitation.

[0187] In order to realize the multiplexing of the same two optical delay lines 320 and 350, as shown in FIG. 13c, the signal processing device can further include the third light combining element 430 and the fourth light splitting element 540 introduced in the case one, and the fourth light combining element 440 and the fifth light splitting element 550 introduced in the case two. The third light combining element 430 and the fourth light splitting element 540 can realize that N first frequency-modulated optoelectronic circuits 110~1N0share the same two optical delay lines 320 and 350, and the fourth light combining element 440 and the fifth light splitting element 550 can realize that M second frequency-modulated optoelectronic circuits 210~2M0share the same two optical delay lines 320 and 350. Therefore, by using the structure shown in FIG. 13c, the plurality of first frequency-modulated optoelectronic circuits and the plurality of second frequency-modulated optoelectronic circuits can share the same two optical delay lines, so that the number of optical delay lines needed to be arranged in the signal processing device can be further saved, thereby realizing the extremely simple architecture and extremely low cost of the signal processing device.

[0188] It should be noted that the related contents of the case one to the case three in the above embodiment one also apply to the case one to the case three in the embodiment two. For example, in the case one to the case three in the embodiment two, the N first frequency-modulated optoelectronic circuits and the one second frequency-modulated optoelectronic circuit, the M second frequency-modulated optoelectronic circuits and the one first frequency-modulated optoelectronic circuit, the N first frequency-modulated optoelectronic circuits and the M second frequency-modulated optoelectronic circuits can also share the same target measurement path, or part of the frequency-modulated optoelectronic circuits share the same target measurement path, and other frequency-modulated optoelectronic circuits have their own separate target measurement path, etc. For another example, in the case one to the case three in the embodiment two, the wavelengths of the to-be-delayed signals in any one first frequency-modulated optoelectronic circuit and the to-be-delayed signals in other first frequency-modulated optoelectronic circuits are different, the wavelengths of the to-be-delayed signals in any one second frequency-modulated optoelectronic circuit and the to-be-delayed signals in other second frequency-modulated optoelectronic circuits are different, and the wavelengths of the to-be-delayed signals in any one first frequency-modulated optoelectronic circuit and the to-be-delayed signals in any one second frequency-modulated optoelectronic circuit can be the same or different, which is not limited in particular.

[0189] In addition, the above two embodiments are only two possible ways of setting the unidirectional light transmission element in the optical delay element 300, and other setting ways can also be used in the actual signal processing device, as long as the function of realizing the reverse transmission of the to-be-delayed signals of the first frequency-modulated optoelectronic circuit and the to-be-delayed signals of the second frequency-modulated optoelectronic circuit on the same optical delay line or multiple optical delay lines can be realized, which is not limited in the present application.

[0190] The specific structure and function of each component in the above figures will be introduced respectively as follows to give an exemplary implementation scheme.

[0191] 1. Light source

[0192] Optionally, the light source can be any device capable of emitting light, such as a laser, including but not limited to: a vertical cavity surface emitting laser (VCSEL), an edge emitting laser (EEL), a diode pumped solid state laser (DPSS), or a fiber laser, etc.

[0193] In one example, the light source can emit a frequency-modulated continuous wave. In other words, the signal processing device can be a device in a FMCW LiDAR.

[0194] 2, light splitting element

[0195] Optionally, the light splitting element can be any device or combination of devices with light splitting function, such as a beam splitter, a beam combiner, a combination of a beam splitter and a beam splitter, or a combination of a beam splitter and a beam combiner, etc.

[0196] Here, the light splitting element can specifically include the first light splitting element in any of the aforementioned first frequency-modulated optoelectronic circuits or second frequency-modulated optoelectronic circuits, the sixth light splitting element in any of the target measurement paths, the second light splitting element, the third light splitting element, the fourth light splitting element, or the fifth light splitting element.

[0197] For example, taking the first light splitting element 112 in FIG. 6 as an example, please refer to FIG. 14a, the first light splitting element 112 can specifically include a first beam splitter 1121 and a second beam splitter 1122. The input end of the first beam splitter 1121 is connected to the output end of the light source 111, the first output end (t 11 ) of the first beam splitter 1121 is connected to the input end of the second beam splitter 1122, the second output end (t 12 ) of the first beam splitter 1121 corresponds to the third output end c 13 of the first light splitting element 112, the first output end (t 21 ) of the second beam splitter 1122 corresponds to the first output end c 11 of the first light splitting element 112, and the second output end (t 22 ) of the second beam splitter 1122 corresponds to the second output end c 12 of the first light splitting element 112. Here, two ends correspond to each other means that the two ends are the same, or the two ends are connected through a line. For example, the second output end t 12 of the first beam splitter 1121 corresponds to the third output end c 13 of the first light splitting element 112, which means that the second output end t 12 of the first beam splitter 1121 is the third output end c13 , or the second output end t 12 The third output end c 13 .

[0198] Based on the above structure and connection relationship, the optical signal S output by the light source 111 enters the first beam splitter 1121, and the first beam splitter 1121 performs optical splitting processing on the optical signal S to obtain a detection signal and a first optical signal (S1). The first beam splitter 1121 outputs the detection signal through its second output end t 12 so that the detection signal enters the target measurement path 113 and participates in target measurement. The first beam splitter 1121 also outputs the first optical signal S1 through its first output end t 11 so that the first optical signal S1 enters the second beam splitter 1122. The second beam splitter 1122 performs optical splitting processing on the first optical signal S1 to obtain a calibration path local oscillator signal and a first to-be-delayed signal S 11 . The second beam splitter 1122 outputs the calibration path local oscillator signal through its second output end t 22 so that the calibration path local oscillator signal directly enters the frequency mixer 114. The second beam splitter 1122 also outputs the first to-be-delayed signal S 21 through its first output end t 11 so that the first to-be-delayed signal S 11 enters the optical delay element 300 and enters the frequency mixer 114 after being delayed by the optical delay element 300.

[0199] It should be noted that the above beam splitter can be any type of beam splitter, such as but not limited to: wavelength type beam splitter, power type beam splitter, polarization type beam splitter, and other types of beam splitter, etc.

[0200] 3. Optical delay element

[0201] As described above, the optical delay element 300 can include an optical delay line and an optical transmission element, and the optical delay line can be the first optical delay line 310 or the second optical delay line 350 described above, and the optical transmission element can be the first optical transmission element 321, the second optical transmission element 322, the third optical transmission element 330, the fourth optical transmission element 340, the first sub-optical transmission element 331, the second sub-optical transmission element 332, the third sub-optical transmission element 341, or the fourth sub-optical transmission element 342 described above.

[0202] Optionally, the optical delay line can be an element capable of delaying the transmission of the optical signal, such as but not limited to an optical fiber delay line or an integrated waveguide delay line, etc. The optical fiber delay line can delay the optical signal by utilizing the transmission of the optical signal in the optical fiber, and generally has a relatively long length. The integrated waveguide delay line is a waveguide device fabricated on a semiconductor chip, and its working principle is to control the propagation path length of electromagnetic waves in a dielectric waveguide or silicon-based or other materials to achieve signal delay. The semiconductor material used by the integrated waveguide delay line can be, for example, silicon (Si), silicon nitride (SiN), etc., and the internal transmission is an optical signal. The integrated waveguide delay line has many advantages, including but not limited to: high integration, good programmability, high delay precision, easy integration with other circuits, smaller size, and adaptation to high-frequency applications, etc.

[0203] Optionally, the optical transmission element can be any device with at least three ports and unidirectional transmission between the ports, such as the circulator shown in FIGS. 4 to 14a, or it can also be an isolator, or it can also be a coupler. Although the coupler cannot completely transmit the delayed signal to the mixer, by setting the interference parameters of each port of the coupler, the input and output signals of each port can be proportionally adjusted, so that most of the delayed signals can also be transmitted to the mixer. Of course, the optical transmission element can also be other devices, which are not limited here.

[0204] 4. The mixer

[0205] The mixer can perform mixing processing on the input signal and output an intermediate frequency signal. Here, the mixer can be the mixer in any of the aforementioned first frequency modulation optoelectronic circuit or second frequency modulation optoelectronic circuit, or the mixer in any of the target measurement paths. For example, in combination with FIG. 6, in the first frequency modulation optoelectronic circuit 110, the mixer 114 can perform mixing processing on the input calibration path local oscillator signal and the first delayed signal S 11 to obtain the intermediate frequency signal corresponding to the calibration path. In the second frequency modulation optoelectronic circuit 210, the mixer 214 can perform mixing processing on the input calibration path local oscillator signal and the second delayed signal S 21 to obtain the intermediate frequency signal corresponding to the calibration path. In the target measurement path 113, the mixer 1133 can perform mixing processing on the input target path local oscillator signal and the received signal to obtain the intermediate frequency signal corresponding to the target path.

[0206] Optionally, the mixer can be any type of optical mixer. For example, taking the mixer 114 in FIG. 6 as an example, in one example, as shown in FIG. 14a, the mixer 114 can be a 180° optical mixer, which has two output ends. The 180° optical mixer can perform mixing processing on the calibration path local oscillator signal and the first delayed signal S 11For example, in one example, as shown in FIG. 14a, the mixer 114 can be a 0° optical mixer having two output ends, and the mixer 114 can perform coherent mixing such that the relative phase difference of the two output ends is 0° and 180°, respectively. For another example, in another example, as shown in FIG. 14b, the mixer 114 can be a 90° optical mixer having four output ends, and the mixer 114 can perform coherent mixing such that the relative phase difference of the four output ends is 0°, 90°, 180°, and 270°, respectively. 11 For example, in one example, as shown in FIG. 14a, the mixer 114 can be a 0° optical mixer having two output ends, and the mixer 114 can perform coherent mixing such that the relative phase difference of the two output ends is 0° and 180°, respectively. For another example, in another example, as shown in FIG. 14b, the mixer 114 can be a 90° optical mixer having four output ends, and the mixer 114 can perform coherent mixing such that the relative phase difference of the four output ends is 0°, 90°, 180°, and 270°, respectively.

[0207] 5. Light detecting element

[0208] The light detecting element, also known as a light receiver, is an electronic device for detecting a light signal and converting the light signal into an electrical signal. Here, the light detecting element can be the light detecting element in any of the aforementioned first frequency-modulated optoelectronic circuits or second frequency-modulated optoelectronic circuits, or the light detecting element in any of the target measurement paths. In each frequency-modulated optoelectronic circuit or its target measurement path, the light detecting element is disposed behind the mixer, and thus it can detect the intermediate frequency signal output by the mixer and convert it into an electrical signal. Optionally, some examples of the light detecting element include, but are not limited to, a phototube, a photomultiplier tube, a photodiode (PD), an avalanche photodiode (APD), a single photon avalanche diode (SPAD), and the like.

[0209] For example, the PD can include at least one PD, and the number of the at least one PD can be the same as the number of the output ends of the mixer arranged in front of the PD. For example, referring to the optical detection element 115 in FIG. 6, in combination with FIG. 6 and FIG. 14a, when the mixer 114 is a 180° optical mixer, the optical detection element 115 can include two PDs, i.e., a PD 11 and a PD 12, the input end of the PD 11 and the input end of the PD 12 are connected to the two output ends of the 180° optical mixer respectively, and the output end of the PD 11 and the output end of the PD 12 are connected to the input end of the amplifier 118. The PD 11 and the PD 12 are used to detect the signals with a phase difference of 0° and 180° output by the two output ends of the 180° optical mixer, and convert the signals into electrical signals, and then the electrical signals are transmitted to the amplifier 118 in one line. For another example, in combination with FIG. 6 and FIG. 14b, when the mixer 114 is a 90° optical mixer, the optical detection element 115 can include four PDs, i.e., a PD 111, a PD 112, a PD 121 and a PD 122, the input ends of the four PDs are connected to the four output ends of the 90° optical mixer respectively, and the output ends of each two PDs are connected to the input end of an amplifier. The four PDs are used to detect the signals with a phase difference of 0°, 90°, 180° and 270° output by the four output ends of the 90° optical mixer, and convert the signals into electrical signals, and then the electrical signals are transmitted to the subsequent amplifier in pairs.

[0210] 6、amplifier

[0211] Optionally, the amplifier can be an element or a combination of elements with signal amplification function. For example, a trans-impedance amplifier (TIA) can be included. The TIA can amplify the input signal with a certain strength and low noise, that is, amplify the useful signal in the input signal while suppressing the amplification of the noise signal, so as to improve the optical signal noise ratio (OSNR).

[0212] For example, taking the TIA as an example, at least one TIA can be included in the amplifier, and the number of at least one TIA can be related to the number of PDs included in the light detection element arranged in front of the TIA, such as half the number of PDs. For example, taking the amplifier 118 in FIG. 6 as an example, in combination with FIG. 6 and FIG. 14a, when the light detection element 115 includes two PDs, i.e., PD11 and PD12, the amplifier 118 can include one TIA, i.e., TIA 1180, and the output ends of PD11 and PD12 are connected to the input end of the TIA 1180 after being combined. Therefore, the two intermediate frequency signals detected by PD11 and PD12 are sent to the TIA 1180 after being combined into one, and the TIA 1180 can amplify the combined intermediate frequency signal to a certain strength. For another example, in combination with FIG. 6 and FIG. 14b, when the light detection element 115 includes four PDs, i.e., PD111, PD112, PD121 and PD122, the amplifier 118 can include two TIAs, i.e., TIA 1181 and TIA 1182, and the output ends of PD111 and PD112 are connected to the input end of the TIA 1181 after being combined, and the output ends of PD121 and PD122 are connected to the input end of the TIA 1182 after being combined. Therefore, the two intermediate frequency signals detected by PD111 and PD112 are sent to the TIA 1181 (referred to as the first intermediate frequency signal Z1) after being combined into one, and the two intermediate frequency signals detected by PD121 and PD122 are sent to the TIA 1182 (referred to as the second intermediate frequency signal Z2) after being combined into one, and the TIA 1181 and the TIA 1182 respectively amplify the first intermediate frequency signal Z1 and the second intermediate frequency signal Z2 to a certain strength.

[0213] 7. Analog-to-digital conversion element

[0214] The analog-to-digital conversion element can sample the received time-continuous and amplitude-continuous analog signal and convert it into a time-discrete and amplitude-discrete digital signal to simplify the software processing operation of the subsequent processing element.

[0215] Optionally, the analog-to-digital conversion element can include at least one analog-to-digital converter (ADC), and the number of the at least one ADC can be the same as the number of the TIAs included in the amplifier arranged in front of the at least one ADC. For example, taking the analog-to-digital conversion element 119 in FIG. 6 as an example, in combination with FIG. 6 and FIG. 14a, when the amplifier 118 includes only one TIA, i.e., the TIA 1180, the analog-to-digital conversion element 119 can include only one ADC, i.e., the ADC 1190, and the input end of the ADC 1190 is connected to the output end of the TIA 1180, so as to perform analog-to-digital conversion on the amplified intermediate frequency signal Z output by the TIA 1180, to obtain a digital signal. For another example, in combination with FIG. 6 and FIG. 14b, when the amplifier 118 includes two TIAs, i.e., the TIA 1181 and the TIA 1182, the analog-to-digital conversion element 119 can also include two ADCs, i.e., the ADC 1191 and the ADC 1192, the input end of the ADC 1191 is connected to the output end of the TIA 1181, and the input end of the ADC 1192 is connected to the output end of the TIA 1182, and the output end of the ADC 1191 and the output end of the ADC 1192 are connected to the input end of the processing element 116 together. The ADC 1191 is configured to perform analog-to-digital conversion on the amplified first intermediate frequency signal Z1 output by the TIA 1181, to obtain a first digital signal, and the ADC 1192 is configured to perform analog-to-digital conversion on the amplified second intermediate frequency signal Z2 output by the TIA 1182, to obtain a second digital signal, and the first digital signal and the second digital signal are input to the processing element 116 together.

[0216] 8、processing element

[0217] The processing element refers to a component with a signal processing function, which can be a digital signal processor (DSP). Taking the processing element 116 in FIG. 6 as an example, as shown in FIG. 14a or FIG. 14b, the processing element 116 can include a DSP 1160, the DSP 1160 can process one or more digital signals output by the analog-to-digital conversion element 119 to obtain a feedback signal P, and input the feedback signal P to the driving circuit 117.

[0218] The feedback signal can be used to calibrate the linearity between the modulation signal output by the driving circuit to the light source and the light signal output by the light source, which is referred to as nonlinearity calibration. There are various ways to achieve nonlinearity calibration, such as but not limited to frequency sweep monitoring and frequency modulation signal pre-distortion. Frequency sweep monitoring refers to calculating the frequency sweep curve by monitoring the change of the modulation signal, and determining whether the frequency sweep curve is linear. If it is not linear, it is calibrated to be linear. Frequency modulation signal pre-distortion refers to compensating the modulation signal that will produce nonlinearity in advance, so that the compensated modulation signal is not distorted, i.e., remains linear. Of course, there can be other ways of nonlinearity calibration, which are not limited here.

[0219] 9. Driving circuit

[0220] In each frequency modulation optoelectronic circuit, the driving circuit can generate a modulation signal according to the feedback signal output by the processing element, and input the modulation signal to the light source. The modulation signal is used to drive the light source to output a light signal whose frequency changes linearly with time, such as a light signal whose frequency changes linearly with time in the form of a triangular wave or a sawtooth wave. In some cases, the driving circuit also needs to be responsible for timing control functions, such as controlling the time window in which the light source emits the light signal, and synchronizing with the receiving end (i.e., the receiving operation of the target measurement path) to accurately demodulate the information in the echo signal (i.e., the received signal).

[0221] It should be noted that the structures shown in Figures 14a and 14b are described by taking the elements on the calibration path (i.e., the path where the first light splitting element 112, the optical delay element 113, the frequency mixer 114, the optical detection element 115, the amplifier 118, the analog-to-digital conversion element 119, and the processing element 116 are located) in the first frequency modulation optoelectronic circuit 110 shown in Figure 6 as an example. The related content of these elements is also applicable to the target measurement path 113 (i.e., the path where the sixth light splitting element 1131, the fifth optical transmission element 1132, the frequency mixer 1133, the optical detection element 1134, the amplifier 1135, the analog-to-digital conversion element 1136, and the processing element 1137 are located) in the first frequency modulation optoelectronic circuit 110 shown in Figure 6, the calibration path (i.e., the path where the first light splitting element 212, the frequency mixer 214, the optical detection element 215, the amplifier 218, the analog-to-digital conversion element 219, and the processing element 216 are located) in the second frequency modulation optoelectronic circuit 210, the target measurement path 213 in the second frequency modulation optoelectronic circuit 210, and the calibration path and the target measurement path in other first frequency modulation optoelectronic circuits or second frequency modulation optoelectronic circuits.

[0222] It can be understood that in the same first frequency modulation optoelectronic circuit or the same second frequency modulation optoelectronic circuit, the mixers in the target measurement path and the mixers in the calibration path can be of the same type or of different types. In different first frequency modulation optoelectronic circuits or different second frequency modulation optoelectronic circuits, the mixers in the calibration path can be of the same type or of different types, and the mixers in the target measurement path can be of the same type or of different types. For example, in combination with the above-mentioned FIG. 6, FIG. 14a, FIG. 14b:

[0223] When the first light splitting element 112 in the first frequency modulation optoelectronic circuit 110 includes the first beam splitter 1121 and the second beam splitter 1122, the mixer 114 is a 180° optical mixer, the light detection element 115 includes the PD11 and the PD12, the amplifier 118 is the TIA 1180, the analog-to-digital conversion element 119 is the ADC 1190, and the processing element 116 is the DSP 1160, the first light splitting element 212 in the second frequency modulation optoelectronic circuit 210 includes the first beam splitter 2121 and the second beam splitter 2122, the mixer 214 is a 90° optical mixer, the light detection element 215 includes the PD131, the PD132, the PD141, and the PD142, the amplifier 218 includes the TIA 2181 and the TIA 2182, the analog-to-digital conversion element 219 includes the ADC 2191 and the ADC 2192, and the processing element 216 is the DSP 2160, the structure of the signal processing device can be specifically as shown in FIG. 14c;

[0224] When the first light splitting element 112 in the first frequency modulation optoelectronic circuit 110 includes the first beam splitter 1121 and the second beam splitter 1122, the mixer 114 is a 180° optical mixer, the light detection element 115 includes the PD11 and the PD12, the amplifier 118 is the TIA 1180, the analog-to-digital conversion element 119 is the ADC 1190, and the processing element 116 is the DSP 1160, the first light splitting element 212 in the second frequency modulation optoelectronic circuit 210 includes the first beam splitter 2121 and the second beam splitter 2122, the mixer 214 is a 180° optical mixer, the light detection element 215 includes the PD13 and the PD14, the amplifier 218 is the TIA 2180, the analog-to-digital conversion element 219 is the ADC 2190, and the processing element 216 is the DSP 2160, the sixth light splitting element 1131 on the target measurement path 113 is the third beam splitter 11310, the mixer 1133 is a 180° optical mixer, the light detection element 1134 includes the PD15 and the PD16, the amplifier 1135 is the TIA 11350, the analog-to-digital conversion element 1136 is the ADC 11360, and the processing element 1137 is the DSP 11370, the structure of the signal processing device can be specifically as shown in FIG. 14d;

[0225] When the first light splitting element 112 in the first frequency modulation optoelectronic circuit 110 comprises a first beam splitter 1121 and a second beam splitter 1122, the frequency mixer 114 is a 90° optical frequency mixer, the light detection element 115 comprises PD 111, PD 112, PD 121 and PD 122, the amplifier 118 comprises a TIA 1181 and a TIA 1182, the analog-to-digital conversion element 119 comprises an ADC 1191 and an ADC 1192, the processing element 116 is a DSP 1160, the first light splitting element 212 in the second frequency modulation optoelectronic circuit 210 comprises a first beam splitter 2121 and a second beam splitter 2122, the frequency mixer 214 is a 180° optical frequency mixer, the light detection element 215 comprises PD 13 and PD 14, the amplifier 218 is a TIA 2180, the analog-to-digital conversion element 219 is an ADC 2190, the processing element 216 is a DSP 2160, the sixth light splitting element 1131 on the target measurement path 113 is a third beam splitter 11310, the frequency mixer 1133 is a 90° optical frequency mixer, the light detection element 1134 comprises PD 151, PD 152, PD 161 and PD 162, the amplifier 1135 comprises a TIA 11351 and a TIA 11352, the analog-to-digital conversion element 1136 comprises an ADC 11361 and an ADC 11362, and the processing element 1137 is a DSP 11370, the structure of the signal processing device can be as shown in FIG. 14e.

[0226] It can be understood that other similar related structures can be obtained by analogy based on the above content, which will not be listed one by one here.

[0227] Based on the structure and functional principle of the signal processing device described above, the present application can also provide a detection device, please refer to FIG. 15. The detection device 1500 comprises a signal processing device 1510, which can be any of the signal processing devices in the above embodiments, such as the signal processing devices shown in FIGS. 4, 5a-5c, 6, 7a, 7b, 8a-8c, 9, 10a-10c, 11, 12, 13a-13c, 14a-14e.

[0228] Optionally, the detection device 1500 can be a laser radar, such as an FMCW LiDAR.

[0229] Optionally, as shown in FIG. 15, the detection device 1500 can further comprise a window 1520 for protecting the internal signal processing device 1510 and can transmit the optical signal emitted by the signal processing device 1510.

[0230] It should be noted that the architecture of the detection device shown in FIG. 15 is only an example, and in other examples, the detection device can include more, less or different structures, and each structure can include more, less or different components, which are not specifically limited in the present application.

[0231] In addition, any existing or future detection device with an optical delay line can adopt the structural design of the above signal processing device. In addition, as the detection technology develops, the structure of the detection device provided in the present application is also applicable to the same technical problem, which is not specifically limited in the present application.

[0232] Based on the structure and functional principle of the detection device described above, the present application can also provide a terminal device, please refer to FIG. 16. The terminal device 1600 includes a detection device 1610, which can be any of the detection devices described above, such as the detection device 1500 shown in FIG. 15.

[0233] Optionally, as shown in FIG. 16, the terminal device 1600 can also include a processor 1620 for calling programs or instructions to control the operation of the detection device 1610. Further, the processor 1620 can also receive the associated information of the target from the detection device 1610. When the terminal device 1600 is a vehicle, the processor 1620 can also perform path planning, braking or starting of the vehicle according to the obtained information. For example, the latitude and longitude can be used to determine the position of the vehicle, or the speed and direction can be used to determine the driving direction and destination of the vehicle in the future, or the distance of the surrounding objects can be used to determine the number and density of obstacles around the vehicle.

[0234] Further, optionally, the terminal device 1600 can also include a memory 1630 for storing programs or instructions. Of course, the terminal device 1600 can also include other devices, such as wireless communication devices, etc.

[0235] The processor 1620 can include one or more processing units. For example, the processor 1620 can include an application processor (AP), an image signal processor (ISP), a controller, a DSP, or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. Different processing units can be independent devices or integrated into one or more processors.

[0236] The memory 1630 includes, but is not limited to, random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically EPROM (EEPROM), registers, a hard disk, a mobile hard disk, a CD-ROM, or any other form of storage medium well known in the art. The storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. Of course, the storage medium can be a component of the processor. The processor and the storage medium can be located in an ASIC.

[0237] For example, the terminal device 1600 described above can be a vehicle (e.g., a self-driving vehicle, a smart vehicle, an electric vehicle, or a digital car), a robot, a surveying device, a drone, a smart home device (e.g., a television, a sweeping robot, a smart table lamp, a sound system, a smart lighting system, an electric appliance control system, a home background music, a home theater system, an intercom system, or a video monitoring device), a smart manufacturing device (e.g., an industrial device), a smart transportation device (e.g., an AGV, a self-driving vehicle, or a truck), or a smart terminal (a mobile phone, a computer, a tablet computer, a palmtop computer, a desktop computer, a headset, a sound system, a wearable device, a vehicle-mounted device, a virtual reality device, an augmented reality device, or the like).

[0238] The above-described various embodiments have consistency in terms and / or descriptions among different embodiments if there is no special description and logical conflict, and the technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0239] In the present application, "at least one" means one or more, and "multiple" means two or more. The "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which can represent the following three cases: A exists alone, A and B exist together, and B exists alone, where A and B can be singular or plural. In the literal description of the present application, the character " / ", generally represents that the front and rear associated objects have an "or" relationship.

[0240] In addition, in the present application, the word "optionally" or "exemplary" means to be given as an example, an instance, or illustration. Any embodiment or design solution described as "optional" or "exemplary" in the present application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Alternatively, it can be understood that the use of the word "exemplary" or "optional" is intended to present a concept in a specific way, and does not constitute a limitation on the present application.

[0241] It can be understood that various numerical numbers involved in the present application are only for the convenience of differentiation, and are not used to limit the scope of the embodiments of the present application. The size of the serial numbers of the above processes does not mean the order of execution, and the execution order of the processes should be determined according to their functions and inherent logic. The terms "first", "second", "third" and the like similar expressions are used to distinguish similar objects, and do not necessarily be used to describe a specific order or sequence. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a series of steps or units. The method, system, product or device is not necessarily limited to those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

Claims

1. A signal processing device, characterized by, The application relates to a signal processing device. The device comprises: a first frequency modulation optoelectronic circuit and a second frequency modulation optoelectronic circuit, each of the first frequency modulation optoelectronic circuit and the second frequency modulation optoelectronic circuit comprising a light source, a first light splitting element, a light delay element, a frequency mixer, a light detecting element, a processing element and a driving circuit; the first frequency modulation optoelectronic circuit and the second frequency modulation optoelectronic circuit share the same light delay element, and the light delay element comprises a first light delay line having a first end and a second end; a signal to be delayed, which is split by the first light splitting element in the first frequency modulation optoelectronic circuit, enters the first end of the first light delay line, is processed by the first light delay line, and is output from the second end of the first light delay line into the frequency mixer in the first frequency modulation optoelectronic circuit; 2. The apparatus of claim 1, wherein, a signal to be delayed, which is split by the first light splitting element in the second frequency modulation optoelectronic circuit, enters the second end of the first light delay line, is processed by the first light delay line, and is output from the first end of the first light delay line into the frequency mixer in the second frequency modulation optoelectronic circuit.

3. The apparatus of claim 1 or 2, wherein, In each frequency modulation optoelectronic circuit, the light signal output by the light source is split by the first light splitting element, is processed by the light delay element, is processed by the frequency mixer, is detected by the light detecting element, is converted into an electric signal, is processed by the processing element, and is used to obtain a feedback signal which is input into the driving circuit, and the feedback signal is used to calibrate the linearity between the modulation signal input into the light source by the driving circuit and the light signal output by the light source. The light delay element further comprises a first light transmission element, and the first light transmission element comprises a first end, a second end and a third end, and the first end to the second end and the second end to the third end are unidirectional transmission; 4. The device of any one of claims 1 to 3, wherein, the first end of the first light transmission element is connected to the first light splitting element in the first frequency modulation optoelectronic circuit, the second end of the first light transmission element is connected to the first end of the first light delay line, and the third end of the first light transmission element is connected to the frequency mixer in the second frequency modulation optoelectronic circuit. The light delay element further comprises a second light transmission element, and the second light transmission element comprises a first end, a second end and a third end, and the first end to the second end and the second end to the third end are unidirectional transmission; 5. The apparatus of claim 4, wherein, the first end of the second light transmission element is connected to the first light splitting element in the second frequency modulation optoelectronic circuit, the second end of the second light transmission element is connected to the second end of the first light delay line, and the third end of the second light transmission element is connected to the frequency mixer in the first frequency modulation optoelectronic circuit. The light delay element further comprises a first light transmission element and a second light transmission element, and the first frequency modulation optoelectronic circuit has N, and N is an integer greater than or equal to 2; The signal processing device further comprises a first light combining element and a second light splitting element; N input ends of the first light combining element are connected to N first light splitting elements in N first frequency modulation optoelectronic circuits in a one-to-one manner, and an output end of the first light combining element is connected to the first end of the first light transmission element. The input end of the second light splitting element is connected to the third end of the second light transmission element, and the N output ends of the second light splitting element are one-to-one connected to N mixers in the N first frequency modulation optoelectronic circuits.

6. The apparatus of claim 4 or 5, wherein, The optical delay element further comprises a first light transmission element and a second light transmission element, and the second frequency modulation optoelectric circuit has M, which is an integer greater than or equal to 2; The signal processing device further comprises a second light combining element and a third light splitting element; The M input ends of the second light combining element are one-to-one connected to M first light splitting elements in the M second frequency modulation optoelectric circuits, and the output end of the second light combining element is connected to the first end of the second light transmission element; The input end of the third light splitting element is connected to the third end of the first light transmission element, and the M output ends of the third light splitting element are one-to-one connected to M mixers in the M second frequency modulation optoelectric circuits.

7. The apparatus of claim 1 or 2, wherein The optical delay element further comprises a third light transmission element and a fourth light transmission element, and the third light transmission element and the fourth light transmission element each comprise a first end, a second end, a third end and a fourth end, and the first end to the second end, the second end to the third end, the third end to the fourth end, and the fourth end to the first end are unidirectional transmission; The first end of the third light transmission element is connected to the first light splitting element in the first frequency modulation optoelectric circuit, the second end of the third light transmission element is connected to the first end of the first optical delay line, the third end of the third light transmission element is connected to the third end of the fourth light transmission element, and the fourth end of the third light transmission element is connected to the mixer in the first frequency modulation optoelectric circuit; The first end of the fourth light transmission element is connected to the first light splitting element in the second frequency modulation optoelectric circuit, the second end of the fourth light transmission element is connected to the second end of the first optical delay line, and the fourth end of the fourth light transmission element is connected to the mixer in the second frequency modulation optoelectric circuit.

8. The apparatus of claim 7, wherein, The third light transmission element comprises a first sub-light transmission element and a second sub-light transmission element, and the first sub-light transmission element and the second sub-light transmission element each comprise a first end, a second end and a third end, and the first end to the second end, the second end to the third end, and the third end to the first end are unidirectional transmission; The first end of the first sub-light transmission element is the first end of the third light transmission element, the second end of the first sub-light transmission element is connected to the first end of the second sub-light transmission element, and the third end of the first sub-light transmission element is the fourth end of the third light transmission element; The second end of the second sub-light transmission element is the second end of the third light transmission element, and the third end of the second sub-light transmission element is the third end of the third light transmission element.

9. The apparatus of claim 7 or 8, wherein, The fourth light transmission element comprises a third sub-light transmission element and a fourth sub-light transmission element, and the third sub-light transmission element and the fourth sub-light transmission element each comprise a first end, a second end and a third end, and the first end to the second end, the second end to the third end, and the third end to the first end are unidirectional transmission; The first end of the third sub-light transmission element is the first end of the fourth light transmission element, the second end of the third sub-light transmission element is connected to the first end of the fourth sub-light transmission element, and the third end of the third sub-light transmission element is the fourth end of the fourth light transmission element; The second end of the fourth sub-light transmission element is the second end of the fourth light transmission element, and the third end of the fourth sub-light transmission element is the third end of the fourth light transmission element.

10. The apparatus of any one of claims 7 to 9, wherein, The optical delay element further comprises a second optical delay line arranged on a connection line between the third end of the third light transmission element and the third end of the fourth light transmission element.

11. The apparatus of any one of claims 7 to 10, wherein, The first frequency modulation optoelectronic circuit has N, and N is an integer greater than or equal to 2; the optical delay element further comprises a third light combining element and a fourth light splitting element; The N input ends of the third light combining element are connected to the N first light splitting elements in the N first frequency modulation optoelectronic circuits one by one, and the output end of the third light combining element is connected to the first end of the third light transmission element; The input end of the fourth light splitting element is connected to the fourth end of the third light transmission element, and the N output ends of the fourth light splitting element are connected to the N mixers in the N first frequency modulation optoelectronic circuits one by one.

12. The apparatus of any one of claims 7 to 11, wherein, The second frequency modulation optoelectronic circuit has M, and M is an integer greater than or equal to 2; the optical delay element further comprises a fourth light combining element and a fifth light splitting element; The M input ends of the fourth light combining element are connected to the M first light splitting elements in the M second frequency modulation optoelectronic circuits one by one, and the output end of the fourth light combining element is connected to the first end of the fourth light transmission element; The input end of the fifth light splitting element is connected to the fourth end of the fourth light transmission element, and the M output ends of the fifth light splitting element are connected to the M mixers in the M second frequency modulation optoelectronic circuits one by one.

13. The apparatus of any one of claims 3 to 12, wherein, One or more of the first light transmission element, the second light transmission element, the third light transmission element, the fourth light transmission element, the first sub-light transmission element, the second sub-light transmission element, the third sub-light transmission element, and the fourth sub-light transmission element is a circulator.

14. The device of any one of claims 1 to 13, wherein, The first optical delay line and / or the second optical delay line is a fiber delay line or an integrated waveguide delay line on a chip.

15. The device of any one of claims 1 to 14, wherein, In each frequency modulation optoelectronic circuit: The optical delay element is connected between the first output end of the first light splitting element and the first input end of the mixer, and the second output end of the first light splitting element is connected to the second input end of the mixer; The first light splitting element is used for splitting the optical signal generated by the light source to obtain a local oscillator signal and a signal to be delayed, and outputs the signal to be delayed through the first output end and outputs the local oscillator signal through the second output end; The mixer is used for mixing the local oscillator signal and the delayed signal to obtain an intermediate frequency signal.

16. The device of any one of claims 1 to 15, wherein, In each frequency modulation optoelectronic circuit: An amplifier and an analog-to-digital converter are further included, and the amplifier and the analog-to-digital converter are connected between the optical detection element and the processing element; The amplifier is used for amplifying the intermediate frequency signal from the optical detection element; The analog-to-digital converter is used for converting the amplified intermediate frequency signal into a digital signal. The analog-to-digital converter is configured to perform analog-to-digital conversion on the amplified intermediate frequency signal to obtain a digital signal.

17. The device of any one of claims 1-16, wherein, In each frequency-modulated optoelectronic circuit: The target measurement path is further connected to a third output end of the first light splitting element. The first light splitting element is further configured to split the light signal generated by the light source to obtain a detection signal and output the detection signal through the third output end. The target measurement path is configured to perform target measurement using the detection signal.

18. The device of any one of claims 1-17, wherein, In each frequency-modulated optoelectronic circuit: The first light splitting element includes a first beam splitter and a second beam splitter, a first output end of the first beam splitter is connected to an input end of the second beam splitter, a second output end of the first beam splitter is connected to a target measurement path, a first output end of the second beam splitter is connected to the optical delay element, and a second output end of the second beam splitter is connected to the frequency mixer. The first beam splitter is configured to split the light signal generated by the light source to obtain a detection signal and an intermediate light signal, output the intermediate light signal through the first output end, and output the detection signal through the second output end. The second beam splitter is configured to split the intermediate light signal to obtain a local signal and a signal to be delayed, output the signal to be delayed through the first output end, and output the local signal through the second output end.

19. A detection device, characterized in that The signal processing device according to any one of claims 1 to 18.

20. A terminal device, comprising: The detection device according to claim 19.

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