Optoelectronic phase-locked loop linear correction system and ranging device

Abstract

Photoelectric phase-locked loop linear correction system and distance measuring device. The application provides a photoelectric phase-locked loop linear correction system, which comprises a light source module, a photoelectric conversion module and a phase-locked loop module. The light source module is used for outputting a laser beam according to a pre-correction signal and a modulation voltage signal. The photoelectric conversion module is electrically connected to the light source module and is used for receiving the laser beam and converting the laser beam into a beat frequency electric signal. The phase-locked loop module is electrically connected to the photoelectric conversion module and the light source module and forms a feedback loop. The phase-locked loop module is used for receiving the beat frequency electric signal and correcting the phase and frequency of the beat frequency electric signal according to the phase and frequency of the reference signal to form the modulation voltage signal. Compared with the prior art, the photoelectric phase-locked loop linear correction system of the application uses the phase-locked loop module as a feedback system to correct the phase and frequency of the beat frequency electric signal according to the phase and frequency of the reference signal and eliminate the high-frequency signal in the beat frequency electric signal, so that the phase-locked loop module realizes high-speed and high-precision correction of the light source module.

Description

Technical Field

[0001] This application belongs to the field of phase-locked loop technology, and more specifically, relates to an optoelectronic phase-locked loop linear correction system and a ranging device. Background Technology

[0002] Frequency-modulated continuous wave (FMCW) absolute range measurement technology originates from the field of traditional microwave radar technology. It modulates the frequency of the transmitted signal in time and obtains target information by measuring the beat frequency between the transmitted and echo signals. At any given instant, by measuring the difference between the transmitted and received signal frequencies, not only the target distance can be measured, but also the target's radial velocity.

[0003] Current-tuned semiconductor lasers have become ideal light sources for frequency-modulated continuous-wave laser absolute distance measurement technology due to their unique advantages. However, current-tuned semiconductor lasers also have the inherent disadvantage of frequency modulation nonlinearity, which becomes more severe as the frequency modulation speed increases. Therefore, it is necessary to precisely control the instantaneous frequency of the laser at high-speed frequency modulation to ensure that its frequency modulation characteristics have good linearity. Summary of the Invention

[0004] The purpose of this application is to provide an optoelectronic phase-locked loop linear correction system and a ranging device to solve the technical problem of frequency-modulated continuous wave laser absolute distance ranging devices being affected by nonlinear frequency modulation in the prior art.

[0005] To achieve the above objectives, the first aspect of this application is to provide an optoelectronic phase-locked loop linear correction system, comprising:

[0006] The light source module is used to emit a laser beam according to the modulation voltage signal;

[0007] A photoelectric conversion module is disposed in the optical path of the laser beam to receive the laser beam and convert the laser beam into a beat frequency electrical signal;

[0008] A phase-locked loop (PLL) module is electrically connected to the photoelectric conversion module and the light source module, and the PLL module, the light source module, and the photoelectric conversion module form a feedback loop; the PLL module is used to receive the beat frequency electrical signal and correct the phase and frequency of the beat frequency electrical signal according to the phase and frequency of the reference signal to generate an error correction signal;

[0009] The phase-locked loop module includes a differential unit, which receives the error correction signal and converts it into two differential signals. The phase-locked loop module then selects the two differential signals in a time-division manner and converts them into modulated voltage signals with positive and negative slopes.

[0010] In one embodiment, the phase-locked loop module further includes:

[0011] A phase detection unit is electrically connected to the photoelectric conversion module and the differential unit. It is used to receive the beat frequency electrical signal, generate a phase detection signal based on the phase difference between the beat frequency electrical signal and the reference signal, and filter the high-frequency signal in the phase detection signal to generate the error correction signal.

[0012] The signal processing unit is electrically connected to the differential unit and the light source module, and is used to receive the differential signal and convert the differential signal into the modulation voltage signal.

[0013] In one embodiment, the phase detection unit includes:

[0014] A phase detector, electrically connected to the photoelectric conversion module, is used to receive the beat frequency electrical signal. The phase detector outputs the phase detection signal based on the phase difference between the beat frequency electrical signal and the reference signal.

[0015] A filter is electrically connected to the phase detector and the differential amplifier unit. The filter is used to receive the phase detection signal and filter out glitches in the phase detection signal to generate the error correction signal.

[0016] In one embodiment, the differential unit includes a differential amplifier connected to the filter;

[0017] The differential amplifier is used to receive the error correction signal and convert the error correction signal into a first differential signal and a second differential signal, wherein the first differential signal and the second differential signal have the same amplitude and opposite polarities.

[0018] In one embodiment, the signal processing unit includes a direction selection unit electrically connected to the differential amplifier;

[0019] The differential amplifier has a first output terminal and a second output terminal, and the direction selection unit has a first access point and a second access point.

[0020] The direction selection unit is used to generate a first switching signal, and select the first access point and the first output terminal in a first timing sequence according to the first switching signal, so that the first differential signal is output from the first output terminal to the first access point;

[0021] The direction selection unit is also used to generate a second switching signal, and select the second access point and the second output terminal in a second timing sequence according to the second switching signal, so that the second differential signal is output from the second output terminal to the second access point;

[0022] The first timing sequence and the second timing sequence are connected alternately in sequence.

[0023] In one embodiment, the direction selection unit includes:

[0024] A selection switch having a first access point and a second access point;

[0025] A direction selection controller is configured to generate a first switching signal and select the first access point and the first output terminal according to the first switching signal in a first timing sequence. The direction selection controller is also configured to generate a second switching signal and select the second access point and the second output terminal according to the second switching signal in a second timing sequence.

[0026] In one embodiment, the signal processing unit further includes an integrator electrically connected to the selection switch;

[0027] The integrator is used to receive the first differential signal and convert the first differential signal into a first error correction voltage signal with a positive slope in the first timing sequence.

[0028] The integrator is used to receive the second differential signal and convert the second differential signal into a second error correction voltage signal with a negative slope in the second timing sequence.

[0029] The integrator is also used to convert the first error correction voltage signal and the second error correction voltage signal into a continuously output error correction voltage signal;

[0030] The error correction voltage signal includes a first error correction voltage signal and a second error correction voltage signal that alternate continuously along a timing sequence, and the timing sequence includes the first timing sequence and the second timing sequence.

[0031] In one embodiment, the signal processing unit further includes:

[0032] A waveform generator is electrically connected to the direction selection controller; the waveform generator is used to generate a first pre-correction signal with a positive slope and a second pre-correction signal with a negative slope, and controls the direction selection controller to generate a first switching signal according to the first pre-correction signal; the waveform generator is also used to control the direction selection controller to generate a second switching signal according to the second pre-correction signal.

[0033] An adder is electrically connected to the waveform generator, the integrator, and the light source module; the adder is used to superimpose the first pre-correction signal and the first error correction voltage signal in the first timing sequence, and to superimpose the second pre-correction signal and the second error correction voltage signal in the second timing sequence to generate the modulation voltage signal.

[0034] In one embodiment, the light source module includes:

[0035] A laser, used to emit a laser beam;

[0036] A laser driver, electrically connected to the adder and the laser, is used to generate a modulation current signal according to the modulation voltage signal, and to excite the laser to emit the laser beam according to the modulation current signal;

[0037] An optical coupler, disposed in the optical path of the laser beam, is used to receive the laser beam and split the laser beam into a probe beam and a reference beam;

[0038] An optical interferometer is disposed in the optical path of the reference beam to receive the reference beam and convert the reference beam into a beat frequency beam;

[0039] The photoelectric conversion unit is disposed in the optical path of the beat frequency beam, and is used to receive the beat frequency beam and convert the reference beam into the beat frequency electrical signal.

[0040] The beneficial effects of the photoelectric phase-locked loop linear correction system provided in this application are as follows: Compared with the prior art, the photoelectric phase-locked loop linear correction system of this application includes a light source module, a photoelectric conversion module, and a phase-locked loop module forming a closed loop. The photoelectric conversion module converts the laser beam into a beat frequency electrical signal. The phase-locked loop module acts as a feedback system to correct the frequency and phase of the beat frequency electrical signal according to the frequency and phase of the reference signal, and removes high-frequency signals from the beat frequency signal, thereby generating a modulation voltage signal with good linearity. The phase-locked loop module then transmits the modulation voltage signal to the light source module, which emits a corresponding light source according to the modulation voltage signal, thus enabling the phase-locked loop module to achieve high-speed and high-precision correction of the light source module. The error correction signal is converted into two differential signals by a differential amplification unit, and the two differential signals are time-division multiplexed, ensuring the consistency of the time delay of the two differential signals, thereby improving the correction accuracy of the photoelectric phase-locked loop linear correction system. Simultaneously, converting the error correction signal into two differential signals by the differential amplification unit also optimizes the structure of the photoelectric phase-locked loop linear correction system.

[0041] On the other hand, this application provides a ranging device, including the photoelectric phase-locked loop linear correction system described in any one of the above claims.

[0042] The beneficial effects of the ranging device provided in this application are as follows: Compared with the prior art, the ranging device of this application includes the photoelectric phase-locked loop linear correction system described above. In this system, the phase-locked loop module in the photoelectric phase-locked loop linear device corrects the frequency and phase of the beat frequency electrical signal by referencing the frequency and phase of the reference signal, and removes high-frequency signals from the beat frequency signal to generate a modulation voltage signal with good linearity. This enables the light source module to emit a corresponding light source according to the modulation voltage signal, thereby achieving high-speed and high-precision correction of the light source module by the phase-locked loop module, thus improving the measurement accuracy of the ranging device. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the structure of the ranging device provided in the embodiments of this application;

[0045] Figure 2 This is a schematic diagram of the structure of the photoelectric phase-locked loop linear correction system provided in the embodiments of this application;

[0046] Figure 3 This is a schematic diagram of the structure of an optical interferometer provided in an embodiment of this application;

[0047] Figure 4 A schematic diagram of the optical interferometer of the ranging device provided in the embodiments of this application.

[0048] The following are the labeling elements in the figure:

[0049] 10. Light source module; 11. Laser driver; 12. Laser;

[0050] 13. Optical coupler; 14. Optical interferometer; 15. Optical isolator;

[0051] 20. Photoelectric conversion module; 21. Balance detector; 30. Phase-locked loop module;

[0052] 31. Phase detection unit; 32. Signal processing unit; 33. Direction selection unit;

[0053] 40. Lens; 50. Object to be tested;

[0054] 141. First coupler; 142. Reference optical path; 143. Second coupler;

[0055] 311. Phase detector; 312. Loop filter; 321. Differential amplifier;

[0056] 322. Integrator; 323. Waveform generator; 324. Adder;

[0057] 331. Selector switch; 332. Direction selection controller. Detailed Implementation

[0058] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0059] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0060] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0061] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0062] Please refer to the following: Figures 1 to 2 The photoelectric phase-locked loop linear correction system provided in the embodiments of this application will now be described.

[0063] The first aspect of this application is to provide a photoelectric phase-locked loop linear correction system, including a light source module 10, a photoelectric conversion module 20, and a phase-locked loop module 30. The light source module 10 is used to adjust the linearity of the system based on a pre-correction signal and a modulation voltage signal U. tThe laser beam is emitted. A photoelectric conversion module 20 is positioned in the optical path of the laser beam to receive it and convert it into a beat frequency electrical signal. A phase-locked loop (PLL) module 30 is electrically connected to the photoelectric conversion module 20 and the light source module 10, forming a feedback loop. The PLL module 30 receives the beat frequency electrical signal and corrects its phase and frequency according to a reference signal to generate an error correction signal U0. The PLL module 30 includes a differential unit that receives the error correction signal U0 and converts it into two differential signals. The PLL module 30 time-division multiplexes the two differential signals and converts them into modulation voltage signals U with positive and negative slopes. t .

[0064] Compared with existing technologies, the photoelectric phase-locked loop linear correction system of this application,

[0065] The system includes a light source module 10, a photoelectric conversion module 20, and a phase-locked loop module 30, forming a closed loop. The photoelectric conversion module 20 converts the laser beam into a beat frequency electrical signal. The phase-locked loop module 30 acts as a feedback system, correcting the frequency and phase of the beat frequency electrical signal based on the frequency and phase of a reference signal, and removing high-frequency signals from the beat frequency signal, thereby generating a modulation voltage signal U with good linearity. t Then the phase-locked loop module 30 modulates the voltage signal U. t The signal is transmitted to the light source module 10, and the light source module 10 modulates the voltage signal U. t The corresponding light source is emitted, enabling the phase-locked loop module 30 to achieve high-speed and high-precision calibration of the light source module 10. The error correction signal U0 is converted into two differential signals by a differential amplifier unit, and these two differential signals are time-division multiplexed to ensure the consistency of their time delays, thereby improving the calibration accuracy of the photoelectric phase-locked loop linear calibration system. Simultaneously, converting the error correction signal U0 into two differential signals by the differential amplifier unit also optimizes the structure of the photoelectric phase-locked loop linear calibration system.

[0066] Specifically, please refer to this application. Figure 1 and Figure 2 The light source module 10, photoelectric conversion module 20, and phase-locked loop module 30 form a feedback loop. The light source module 10 generates a laser beam based on a pre-calibration signal. The photoelectric conversion module 20 converts a portion of the laser beam into a probe beam and another portion into a reference beam, with the ratio of the portion converted to the reference beam to the portion converted to the probe beam being 10:90. The photoelectric conversion module 20 receives the reference beam, converts it into a beat frequency electrical signal, and transmits the beat frequency electrical signal to the phase-locked loop module 30.

[0067] After receiving the beat frequency electrical signal, the phase-locked loop module 30 compares the frequency and phase of the beat frequency electrical signal with the frequency and phase of the reference signal. A phase detection signal is generated based on the phase difference between the beat frequency electrical signal and the reference signal. Then, glitches in the phase detection signal are identified based on the frequency difference between the phase detection signal and the reference signal, and these glitches are filtered to generate an error correction signal U0. Subsequently, the phase-locked loop module 30 converts the error correction signal U0 into a first differential signal U1 and a second differential signal U2 with the same amplitude but opposite polarities. The first differential signal U1 and the second differential signal U2 are then integrated to generate an error correction voltage signal U with positive and negative slopes. d Then the error correction voltage signal U d It is superimposed on the pre-correction signal to generate a modulated voltage signal U with correction information. t Subsequently, the light source module 10 receives the modulated voltage signal U. t And according to the modulated voltage signal U t The emitted laser beam.

[0068] In one embodiment of this application, the phase-locked loop module 30 includes a phase detection unit 31 and a signal processing unit 32. The phase detection unit 31 is electrically connected to the photoelectric conversion module 20 and is used to receive a beat frequency electrical signal, generate a phase detection signal based on the phase difference between the beat frequency electrical signal and a reference signal, and filter glitches in the phase detection signal to generate an error correction signal U0. The signal processing unit 32 is electrically connected to the phase detection unit 31 and is used to receive the error correction signal U0 and convert the error correction signal U0 into a modulation voltage signal U. t .

[0069] Specifically, please refer to Figure 1 and Figure 2 In the embodiments of this application, the phase detection unit 31 includes a phase detector 311 and a filter. The phase detector 311 is electrically connected to the photoelectric conversion module 20, and is used to receive the beat frequency electrical signal, and output a phase detection signal according to the phase difference between the beat frequency electrical signal and the reference signal, thereby locking the phase of the reference signal with the beat frequency electrical signal. The filter is electrically connected to the phase detector 311 and the signal processing unit 32, and is used to receive the phase detection signal, and filter out the glitches in the phase detection signal to generate an error correction signal U0, thereby synchronizing the frequency of the error correction signal U0 with the frequency of the reference signal.

[0070] In one embodiment of this application, the signal processing unit 32 includes a differential amplifier 321 connected to the phase detector unit 31, for receiving an error correction signal U0 and converting the error correction signal U0 into a first differential signal U1 and a second differential signal U2 with the same amplitude and opposite polarity.

[0071] Specifically, please refer to Figure 1 and Figure 2 In this application, the differential amplifier 321 is electrically connected to the loop filter 312 to receive the error correction signal U0 generated by the loop filter 312, and converts the error correction signal U0 into a first differential signal U1 and a second differential signal U2 and selects them in a time-division manner. The first differential signal U1 and the second differential signal U2 have the same amplitude and opposite polarities.

[0072] The error correction signal U0 is converted into a first differential signal U1 and a second differential signal U2 with the same amplitude but opposite polarity by a differential amplifier 321. The first differential signal U1 and the second differential signal U2 are time-division multiplexed, ensuring the consistency of their time delays and thus improving the correction accuracy of the photoelectric phase-locked loop linear correction system. Furthermore, converting the error correction signal U0 into the first differential signal U1 and the second differential signal U2 with the same amplitude but opposite polarity by differential amplifier 321 also optimizes the structure of the photoelectric phase-locked loop linear correction system.

[0073] In one embodiment of this application, the signal processing unit 32 further includes a direction selection unit 33. The direction selection unit is electrically connected to the differential amplifier 321, which has a first output terminal and a second output terminal. The direction selection unit 33 has a first access point and a second access point. The direction selection unit 33 generates a first switching signal and selects the first access point and the first output terminal according to the first switching signal in a first timing sequence, so that the first differential signal U1 is output from the first output terminal to the first access point. The direction selection unit 33 also generates a second switching signal and selects the second access point and the second output terminal according to the second switching signal in a second timing sequence, so that the second differential signal U2 is output from the second output terminal to the second access point. The first timing sequence and the second timing sequence are alternately connected sequentially.

[0074] Specifically, in the embodiments of this application, please refer to Figure 1 and Figure 2 The direction selection unit 33 includes a selection switch 331 and a direction selection controller 332. The selection switch 331 has a first access point and a second access point. The direction selection controller 332 is electrically connected to the selection switch 331 and is used to generate a first switching signal in a first timing sequence and a second switching signal in a second timing sequence.

[0075] The direction selection controller 332 controls the selection switch 331 via a first switching signal to select the first access point and the first output terminal in a first timing sequence, so that the first differential signal U1 is output from the first output terminal and passes through the first access point within the first timing sequence. The direction selection controller 332 controls the selection switch 331 via a second switching signal to select the second access point and the second output terminal in a second timing sequence, so that the second differential signal U2 is output from the second output terminal and passes through the second access point within the second timing sequence. The first and second timing sequences are alternately connected, thereby the switching switch continuously outputs the first differential signal U1 and the second differential signal U2.

[0076] In one embodiment of this application, the signal processing unit 32 further includes an integrator 322. The integrator 322 is electrically connected to the selection switch 331.

[0077] Specifically, in the implementation of this application, please refer to Figure 1 and Figure 2 Since the amplitudes of the first differential signal U1 and the second differential signal U2 are the same but their polarities are opposite, the continuous output of the switching switch results in a square wave signal that is mutually broken between the first differential signal U1 and the second differential signal U2. Furthermore, the current signal used by the control light source module 10 to generate the laser beam is a triangular wave. Therefore, an integrator 322 is needed to process the first differential signal U1 and the second differential signal U2.

[0078] Error correction voltage signal U d It includes a first error correction voltage signal and a second error correction voltage signal that are alternately set in a time sequence, wherein the slope of the first error correction voltage signal is positive and the slope of the second error correction voltage signal is negative.

[0079] Integrator 322 is used to receive a first differential signal U1 and convert it into a first error correction voltage signal with a positive slope in a first timing sequence. Integrator 322 is also used to receive a second differential signal U2 and convert it into a second error correction voltage signal with a negative slope in a second timing sequence. Furthermore, integrator 322 is used to convert the first and second error correction voltage signals into a continuously output error correction voltage signal U. d The timing sequence includes the first timing sequence and the second timing sequence.

[0080] Error correction voltage signal U d The up-sweep frequency corresponds to the positive slope portion of the error correction signal U0, and the error correction voltage signal U d The downsweep frequency corresponds to the negative slope portion of the error correction signal U0. The first differential signal U1 has a positive polarity, and the second differential signal U2 has a negative polarity. The integrator 322 converts the first differential signal U1 and the second differential signal U2 into an error correction voltage signal U.d Then, the first differential signal U1 corresponds to the upper frequency sweep of the error correction signal U0, and the second differential signal U2 corresponds to the lower frequency sweep of the error correction signal U0.

[0081] In one embodiment of this application, the signal processing unit 32 further includes a waveform generator 323 and an adder 324. The waveform generator 323 is electrically connected to the adder 324 and the direction selection controller 332, and is used to generate a pre-correction signal. The adder 324 is electrically connected to the integrator 322 and the light source module 10, and is used to superimpose the pre-correction signal and the error correction voltage signal U. d To form a modulated voltage signal U t The waveform generator 323 generates a pre-correction signal as a synchronous trigger signal for the switching signal generated by the direction selection controller 332.

[0082] Specifically, in the embodiments of this application, please refer to Figure 1 and Figure 2 The pre-calibration signal includes a first pre-calibration signal with a positive slope and a second pre-calibration signal with a negative slope. Waveform generator 323 is electrically connected to direction selection controller 332, and adder 324 is electrically connected to waveform generator 323, integrator 322 and light source module 10.

[0083] Waveform generator 323 generates a first pre-correction signal in a first timing sequence and a second pre-correction signal in a second timing sequence. Waveform generator 323 controls direction selection controller 332 to generate a first switching signal in the first timing sequence via the first pre-correction signal, and controls direction selection controller 332 to generate a second switching signal in the second timing sequence via the second pre-correction signal. Since the slope of the first error correction voltage signal is positive and the slope of the second error correction voltage signal is negative, adder 324 superimposes the first pre-correction signal and the first error correction voltage signal in the first timing sequence, and superimposes the second pre-correction signal and the second error correction voltage signal in the second timing sequence to generate a modulated voltage signal U. t And output it.

[0084] A waveform generator 323 is added to the phase-locked loop module 30. By inputting pre-correction parameters into the waveform generator 323, the waveform generator 323 generates a pre-correction signal, thereby reducing the phase difference between the initial beat frequency electrical signal and the reference signal, and thus improving the speed at which the beat frequency electrical signal locks the phase of the reference signal.

[0085] In one embodiment of this application, the light source module 10 includes a laser driver 11, a laser 12, an optical coupler 13, and an optical interferometer 14. The laser driver 11 is electrically connected to the adder 324 and the laser 12, and is used to adjust the voltage signal U according to the modulation voltage signal U. t Generate modulated current signal I tLaser 12 is electrically connected to laser driver 11, and laser driver 11 operates according to modulation current signal I. t The laser 12 is activated to emit a laser beam.

[0086] Optical coupler 13 is positioned in the optical path of the laser beam to receive the laser beam and split it into a probe beam and a reference beam. Optical interferometer 14 is positioned in the optical path of the reference beam to receive the reference beam and convert it into a beat frequency beam. Photoelectric conversion module 20 is positioned in the optical path of the beat frequency beam to receive the beat frequency beam and convert the reference beam into a beat frequency signal.

[0087] Specifically, in the embodiments of this application, please refer to Figure 2 and Figure 3 The optical interferometer 14 is a Mach-Zehnder interferometer, the photoelectric conversion module 20 is a balanced detector 21, the reference beam is received by the balanced detector 21, and the balanced detector 21 is used to convert the reference beam into a beat frequency electrical signal.

[0088] An optical isolator 15 is provided between the optical interferometer 14 and the laser 12 to block laser beams that are opposite in direction to the laser beam emitted by the laser 12. The optical interferometer 14 includes a first coupler 141, a reference optical path 142, and a second coupler 143, wherein the reference optical path 142 is an optical fiber.

[0089] After receiving the laser beam, the optical interferometer 14 uses an optical coupler to split the laser beam into a reference beam and a probe beam at a ratio of 10:90.

[0090] The probe beam illuminates the object under test 50 to measure the distance between the object under test 50 and the photoelectric phase-locked loop linear correction system. The reference beam illuminates the optical interferometer 14. The reference optical path 142 has two optical paths for beam transmission. The reference beam is split into a long-wavelength beat frequency beam and a short-wavelength beat frequency beam by a first coupler 141 with a beam splitting ratio of 50:50. The long-wavelength beat frequency beam and the short-wavelength beat frequency beam are then transmitted by the two optical paths respectively. Then, the long-wavelength beat frequency beam and the short-wavelength beat frequency beam are output through a second coupler 143 with a ratio of 50:50 in their respective optical paths to generate a beat frequency beam. The beat frequency beam generates a beat signal on the photosensitive surface of the balanced detector 21, thereby causing the balanced detector 21 to output a beat frequency electrical signal.

[0091] On the other hand, embodiments of this application provide a ranging device, including the photoelectric phase-locked loop linear correction system provided in the above embodiments.

[0092] Compared with the prior art, the ranging device of this application includes the photoelectric phase-locked loop linear correction system provided in the above embodiments. The phase-locked loop module 30 in the photoelectric phase-locked loop linear device corrects the frequency and phase of the beat frequency electrical signal by referencing the frequency and phase of the reference signal, and removes high-frequency signals from the beat frequency signal to generate a modulation voltage signal U with good linearity. t The light source module 10 is regulated according to the modulation voltage signal U. t The corresponding light source is emitted, enabling the phase-locked loop module 30 to perform high-speed and high-precision calibration of the light source module 10, thereby improving the measurement accuracy of the ranging device.

[0093] For details, please refer to the following: Figure 1 and Figure 4 In this embodiment, the optical coupler in the photoelectric phase-locked loop linear correction system is disposed in the optical path of the laser beam to receive the laser beam and split the laser beam into a probe beam and a reference beam. The optical coupler is connected to a lens 40. The laser 12 is a tunable laser 12, so that the frequency of the laser beam can be linearly modulated.

[0094] In this process, by injecting an appropriate driving current into the tunable laser 12, its output laser signal is made to sweep with a time-linear triangular wave frequency. After passing through an isolator, the beam is split into a reference beam and a probe beam by an optical coupler with a splitting ratio of 10:90. The probe beam is emitted into free space through the lens 40 to illuminate the object 50 under test. The reflected light from the probe beam is received by the lens 40 to determine the distance between the ranging device and the object 50 under test. At the same time, the reference beam is converted into a beat frequency beam by the optical interferometer 14. The beat frequency beam is converted into a beat frequency electrical signal by the balanced detector 21. Subsequently, the phase-locked loop module 30 corrects the phase and frequency of the beat frequency electrical signal according to the phase and frequency of the reference signal to generate a modulation voltage signal U with good linearity. t and modulate the voltage signal U t The signal is transmitted to the light source module 10 so that the light source module 10 can transmit the signal according to the modulation voltage signal U. t A laser light source is emitted to enable the phase-locked loop module 30 to perform high-speed and high-precision calibration of the light source module 10.

[0095] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A photoelectric phase-locked loop linear correction system, characterized in that, include: The light source module is used to emit a laser beam according to the modulation voltage signal; A photoelectric conversion module is disposed in the optical path of the laser beam to receive the laser beam and convert the laser beam into a beat frequency electrical signal; A phase-locked loop (PLL) module is electrically connected to the photoelectric conversion module and the light source module, and the PLL module, the light source module, and the photoelectric conversion module form a feedback loop. The PLL module includes a phase detection unit, a differential unit, and a signal processing unit. The phase detection unit is electrically connected to the photoelectric conversion module and the differential unit, and is used to receive the beat frequency electrical signal, generate a phase detection signal based on the phase difference between the beat frequency electrical signal and a reference signal, and filter high-frequency signals in the phase detection signal to generate an error correction signal. The differential unit is used to receive the error correction signal and convert the error correction signal into two differential signals. The phase-locked loop module selects the two differential signals in a time-division manner and converts the two differential signals into modulated voltage signals with positive and negative slopes. The signal processing unit is electrically connected to the differential unit and the light source module, and is used to receive the differential signal and convert the differential signal into the modulation voltage signal.

2. The photoelectric phase-locked loop linear correction system as described in claim 1, characterized in that, The phase detection unit includes: A phase detector, electrically connected to the photoelectric conversion module, is used to receive the beat frequency electrical signal. The phase detector outputs the phase detection signal based on the phase difference between the beat frequency electrical signal and the reference signal. A filter, electrically connected to the phase detector and the differential amplifier unit, is used to receive the phase detection signal and filter out glitches in the phase detection signal to generate the error correction signal.

3. The photoelectric phase-locked loop linear correction system as described in claim 2, characterized in that, The differential unit includes a differential amplifier, which is connected to the filter; The differential amplifier is used to receive the error correction signal and convert the error correction signal into a first differential signal and a second differential signal, wherein the first differential signal and the second differential signal have the same amplitude and opposite polarities.

4. The photoelectric phase-locked loop linear correction system as described in claim 3, characterized in that, The signal processing unit includes a direction selection unit, which is electrically connected to the differential amplifier; The differential amplifier has a first output terminal and a second output terminal, and the direction selection unit has a first access point and a second access point. The direction selection unit is used to generate a first switching signal, and select the first access point and the first output terminal in a first timing sequence according to the first switching signal, so that the first differential signal is output from the first output terminal to the first access point; The direction selection unit is also used to generate a second switching signal, and select the second access point and the second output terminal in a second timing sequence according to the second switching signal, so that the second differential signal is output from the second output terminal to the second access point; The first timing sequence and the second timing sequence are connected alternately in sequence.

5. The photoelectric phase-locked loop linear correction system as described in claim 4, characterized in that, The direction selection unit includes: A selection switch having a first access point and a second access point; A direction selection controller is configured to generate a first switching signal and select the first access point and the first output terminal according to the first switching signal in a first timing sequence. The direction selection controller is also configured to generate a second switching signal and select the second access point and the second output terminal according to the second switching signal in a second timing sequence.

6. The photoelectric phase-locked loop linear correction system as described in claim 5, characterized in that, The signal processing unit further includes an integrator, which is electrically connected to the selection switch; The integrator is used to receive the first differential signal and convert the first differential signal into a first error correction voltage signal with a positive slope in the first timing sequence. The integrator is used to receive the second differential signal and convert the second differential signal into a second error correction voltage signal with a negative slope in the second timing sequence; The integrator is also used to convert the first error correction voltage signal and the second error correction voltage signal into a continuously output error correction voltage signal; The error correction voltage signal includes a first error correction voltage signal and a second error correction voltage signal that alternate continuously along a timing sequence, and the timing sequence includes the first timing sequence and the second timing sequence.

7. The photoelectric phase-locked loop linear correction system as described in claim 6, characterized in that, The signal processing unit further includes: A waveform generator is electrically connected to the direction selection controller; the waveform generator is used to generate a first pre-correction signal with a positive slope and a second pre-correction signal with a negative slope, and controls the direction selection controller to generate a first switching signal according to the first pre-correction signal; the waveform generator is also used to control the direction selection controller to generate a second switching signal according to the second pre-correction signal. An adder is electrically connected to the waveform generator, the integrator, and the light source module; the adder is used to superimpose the first pre-correction signal and the first error correction voltage signal in the first timing sequence, and to superimpose the second pre-correction signal and the second error correction voltage signal in the second timing sequence to generate the modulation voltage signal.

8. The photoelectric phase-locked loop linear correction system as described in claim 7, characterized in that, The light source module includes: A laser, used to emit a laser beam; A laser driver, electrically connected to the adder and the laser, is used to generate a modulation current signal according to the modulation voltage signal, and to excite the laser to emit the laser beam according to the modulation current signal; An optical coupler, disposed in the optical path of the laser beam, is used to receive the laser beam and split the laser beam into a probe beam and a reference beam; An optical interferometer is disposed in the optical path of the reference beam to receive the reference beam and convert the reference beam into a beat frequency beam; An optoelectronic conversion unit is disposed in the optical path of the beat frequency beam to receive the beat frequency beam and convert the reference beam into the beat frequency electrical signal.

9. A ranging device, characterized in that, include: The photoelectric phase-locked loop linear correction system as described in any one of claims 1-8.

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