CN116626655A - Photoelectric phase-locked loop linearity correction system and distance measuring device - Google Patents
Photoelectric phase-locked loop linearity correction system and distance measuring device Download PDFInfo
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- CN116626655A CN116626655A CN202210134112.0A CN202210134112A CN116626655A CN 116626655 A CN116626655 A CN 116626655A CN 202210134112 A CN202210134112 A CN 202210134112A CN 116626655 A CN116626655 A CN 116626655A
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/497—Means for monitoring or calibrating
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/08—Systems determining position data of a target for measuring distance only
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/08—Systems determining position data of a target for measuring distance only
- G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
- H03L7/00—Automatic control of frequency or phase; Synchronisation
- H03L7/06—Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop
- H03L7/08—Details of the phase-locked loop
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- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
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- Electromagnetism (AREA)
- Instruments For Measurement Of Length By Optical Means (AREA)
- Optical Radar Systems And Details Thereof (AREA)
Abstract
An optoelectronic phase-locked loop linear correction system and a distance measuring device. The application provides a linear correction system of a photoelectric phase-locked loop, which comprises a light source module, a photoelectric conversion module and a phase-locked loop module. The light source module is used for outputting and emitting laser beams according to the pre-correction signal and the 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 with the photoelectric conversion module and the light source module and forms a feedback loop, and is used for receiving the beat frequency electric signal and correcting the phase and the frequency of the beat frequency electric signal according to the phase and the frequency of the reference signal so as to form a modulation voltage signal. Compared with the prior art, the photoelectric phase-locked loop linear correction system has the advantages that the phase-locked loop module is used as a feedback system for correcting the phase and the frequency of the beat frequency electric signal according to the phase and the frequency of the reference signal, and the high-frequency signal in the beat frequency electric signal is removed, so that the phase-locked loop module can realize high-speed and high-precision correction of the light source module.
Description
Technical Field
The application belongs to the technical field of phase-locked loops, and particularly relates to a photoelectric phase-locked loop linearity correction system and a ranging device.
Background
Frequency Modulated Continuous Wave (FMCW) absolute distance measurement techniques originate from the traditional microwave radar technology field, which modulates the frequency of a transmitted signal over time and obtains target information by measuring the beat signal frequency of the transmitted signal and an echo signal. At any given instant, not only the target distance, but also the radial velocity of the target can be measured by measuring the difference between the transmitted signal frequency and the received frequency.
Current-tuned semiconductor lasers are ideal light sources for fm continuous wave laser absolute distance measurement techniques because of their unique advantages, but current-tuned semiconductor lasers suffer from inherent fm nonlinearities and become increasingly nonlinear as fm speeds increase. Therefore, the instantaneous frequency of the laser under high-speed frequency modulation must be precisely controlled, so that the frequency modulation characteristic has good linearity.
Disclosure of Invention
The embodiment of the application aims to provide a photoelectric phase-locked loop linearity correction system and a ranging device, which are used for solving the technical problem that a frequency modulation continuous wave laser absolute distance ranging device in the prior art is affected by nonlinear frequency modulation.
To achieve the above object, a first aspect of the present application provides an optical-electric phase-locked loop linearity correction system, including:
the light source module is used for emitting laser beams according to the modulated voltage signals;
the photoelectric conversion module is arranged on the optical path of the laser beam 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 with the photoelectric conversion module and the light source module, and the phase-locked loop module, the light source module and the photoelectric conversion module form a feedback loop; the phase-locked loop module is used for receiving the beat frequency electric signal and correcting the phase and the frequency of the beat frequency electric signal according to the phase and the frequency of the reference signal so as to generate an error correction signal;
the phase-locked loop module is internally provided with a differential unit, the differential unit is used for receiving the error correction signal and converting the error correction signal into two paths of differential signals, and the phase-locked loop module time-sharing gates the two paths of differential signals and converts the two paths of differential signals into modulated voltage signals with positive and negative slopes.
In one embodiment, the phase-locked loop module further comprises:
the phase discrimination unit is electrically connected with the photoelectric conversion module and the differential unit and is used for receiving the beat frequency electric signal, generating a phase discrimination signal according to the phase difference between the beat frequency electric signal and the reference signal, and filtering a high-frequency signal in the phase discrimination signal to generate the error correction signal;
the signal processing unit is electrically connected with the differential unit and the light source module and is used for receiving the differential signal and converting the differential signal into the modulation voltage signal.
In one embodiment, the phase discrimination unit includes:
the phase discriminator is electrically connected with the photoelectric conversion module and is used for receiving the beat frequency electric signal and outputting a phase discrimination signal according to the phase difference between the beat frequency electric signal and the reference signal;
the filter is electrically connected with the phase discriminator and the differential amplifying unit, and is used for receiving the phase discriminator signal and filtering burr signals in the phase discriminator signal to generate the error correction signal.
In one embodiment, the differential unit includes a differential amplifier, and the differential amplifier is connected to the filter;
the differential amplifier is used for receiving the error correction signal and converting 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.
In one embodiment, the signal processing unit includes a direction selecting unit, and the direction selecting unit is electrically connected to the differential amplifier;
the differential amplifier is provided with a first output end and a second output end, and the direction selection unit is provided with a first access point and a second access point;
the direction selection unit is used for generating a first switching signal, and gating the first access point and the first output end at a first time sequence according to the first switching signal so that the first differential signal is output to the first access point from the first output end;
the direction selection unit is further configured to generate a second switching signal, and gate the second access point and the second output end at a second timing sequence according to the second switching signal, so that the second differential signal is output to the second access point from the second output end;
wherein the first timing sequence and the second timing sequence are alternately connected in turn.
In one embodiment, the direction selecting unit includes:
a selection switch having the first access point and the second access point;
the direction selection controller is used for generating the first switching signal, gating the first access point and the first output end at the first time sequence according to the first switching signal, and generating the second switching signal, and gating the second access point and the second output end at the second time sequence according to the second switching signal.
In an embodiment, the signal processing unit further includes an integrator, and the integrator is electrically connected to the selection switch;
the integrator is configured to receive the first differential signal and convert the first differential signal into a first error correction voltage signal having a positive slope at the first timing;
the integrator is used for receiving the second differential signal and converting the second differential signal into a second error correction voltage signal with a negative slope at the second time sequence;
the integrator is further configured to convert the first error correction voltage signal and the second error correction voltage signal into continuously output error correction voltage signals;
the error correction voltage signal comprises a first error correction voltage signal and a second error correction voltage signal which are sequentially and alternately continuous along a time sequence, and the time sequence comprises the first time sequence and the second time sequence.
In an embodiment, the signal processing unit further comprises:
the waveform generator is electrically connected with the direction selection controller; the waveform generator is used for generating a first pre-correction signal with a positive slope and a second pre-correction signal with a negative slope, controlling the direction selection controller to generate the first switching signal according to the first pre-correction signal, and controlling the direction selection controller to generate the second switching signal according to the second pre-correction signal;
the adder is electrically connected with the waveform generator, the integrator and the light source module; the adder is configured to superimpose the first pre-correction signal and the first error correction voltage signal at the first timing, and to superimpose the second pre-correction signal and the second error correction voltage signal at a second timing to generate the modulated voltage signal.
In one embodiment, the light source module includes:
a laser for emitting a laser beam;
the laser driver is electrically connected with the adder and the laser and is used for generating a modulation current signal according to the modulation voltage signal and exciting the laser to emit the laser beam according to the modulation current signal;
the optical coupler is arranged on the optical path of the laser beam and is used for receiving the laser beam and splitting the laser beam into a detection beam and a reference beam;
the optical interferometer is arranged on the optical path of the reference beam and is used for receiving the reference beam and converting the reference beam into a beat frequency beam;
the photoelectric conversion unit is arranged on the optical path of the beat frequency light beam and is used for receiving the beat frequency light beam and converting the reference light beam into the beat frequency electric signal.
The photoelectric phase-locked loop linearity correction system provided by the application has the beneficial effects that: compared with the prior art, the photoelectric phase-locked loop linear correction system comprises a light source module, a photoelectric conversion module and a phase-locked loop module which form a closed loop, wherein the photoelectric conversion module converts a laser beam into a beat frequency electric signal, the phase-locked loop module is used as a feedback system and is used for correcting the frequency and the phase of the beat frequency electric signal according to the frequency and the phase of a reference signal, and eliminating high-frequency signals in the beat frequency electric signal so as to generate a modulated voltage signal with good linearity, then the phase-locked loop module transmits the modulated voltage signal to the light source module, and the light source module transmits a corresponding light source according to the modulated voltage signal, so that the phase-locked loop module realizes high-speed and high-precision correction of the light source module; the error correction signal is converted into two paths of differential signals through the differential amplification unit, and the two paths of differential signals are time-division gated, so that the consistency of time delay of the two paths of differential signals is ensured, and the correction precision of the photoelectric phase-locked loop linear correction system is improved; meanwhile, the error correction signal is converted into two paths of differential signals through the differential amplification unit, and the structure of the linear correction system of the photoelectric phase-locked loop can be optimized.
In another aspect, the present application provides a ranging device, including an electro-optical phase-locked loop linearity correction system as described in any of the above.
The distance measuring device provided by the application has the beneficial effects that: compared with the prior art, the ranging device comprises the photoelectric phase-locked loop linear correction system, wherein the phase-locked loop module in the photoelectric phase-locked loop linear device corrects the frequency and the phase of the beat frequency electric signal through the frequency and the phase of the reference signal, eliminates the high-frequency signal in the beat frequency signal to generate a modulation voltage signal with good linearity, and enables the light source module to emit a light source corresponding to the modulation voltage signal according to the modulation voltage signal, so that the phase-locked loop module realizes high-speed and high-precision correction of the light source module, and the measurement precision of the ranging device is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of a ranging device according to an embodiment of the present application;
fig. 2 is a schematic structural diagram of an optical-electrical phase-locked loop linearity correction system according to an embodiment of the present application;
FIG. 3 is a schematic diagram of an optical interferometer according to an embodiment of the present application;
fig. 4 is a schematic structural diagram of an optical interferometer of the ranging apparatus according to an embodiment of the present application.
Wherein, each reference sign in the figure:
10. a light source module; 11. A laser driver; 12. A laser;
13. an optical coupler; 14. An optical interferometer; 15. An optical isolator;
20. a photoelectric conversion module; 21. A balance detector; 30. A phase-locked loop module;
31. a phase discrimination unit; 32. A signal processing unit; 33. A direction selection unit;
40. a lens; 50. An object to be measured;
141. a first coupler; 142. A reference light path; 143. A second coupler;
311. a phase detector; 312. A loop filter; 321. A differential amplifier;
322. an integrator; 323. A waveform generator; 324. An adder;
331. a selection switch; 332. A direction selection controller.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.
It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are merely for convenience in describing and simplifying the description based on the orientation or positional relationship shown in the drawings, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the application.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
Referring to fig. 1 to 2, an embodiment of an electro-optical phase locked loop linearity correction system according to the present application will now be described.
A first aspect of the present application provides a system for linear correction of an optical-to-electrical phase-locked loop, which includes a light source module 10, an optical-to-electrical conversion module 20, and a phase-locked loop module 30. Wherein the light source module 10 is used for adjusting the voltage signal U according to the pre-correction signal t Outputting the emitted laser beam. The photoelectric conversion module 20 is disposed on the optical path of the laser beam for receiving the laser beamAnd converts the laser beam into a beat signal. The phase-locked loop module 30 is electrically connected to the photoelectric conversion module 20 and the light source module 10, and the phase-locked loop module 30, the light source module 10 and the photoelectric conversion module 20 form a feedback loop, and the phase-locked loop module 30 is configured to receive the beat signal and correct the phase and frequency of the beat signal according to the phase and frequency of the reference signal to generate an error correction signal U 0 The method comprises the steps of carrying out a first treatment on the surface of the The phase-locked loop module 30 is provided with a differential unit for receiving the error correction signal U 0 And error correction signal U 0 Is converted into two differential signals, and the phase-locked loop module 30 time-division gates the two differential signals and converts the two differential signals into a modulated voltage signal U with positive and negative slopes t 。
Compared with the prior art, the photoelectric phase-locked loop linear correction system of the application,
comprises a light source module 10 forming a closed loop, a photoelectric conversion module 20 and a phase-locked loop module 30, wherein the photoelectric conversion module 20 converts a laser beam into a beat signal, the phase-locked loop module 30 is used as a feedback system for correcting the frequency and the phase of the beat signal according to the frequency and the phase of a reference signal and eliminating high-frequency signals in the beat signal so as to generate a modulation voltage signal U with good linearity t The phase-locked loop module 30 then modulates the voltage signal U t Is transmitted to the light source module 10, and the light source module 10 modulates the voltage signal U according to the modulation voltage signal t The corresponding light source is emitted, thereby enabling the phase-locked loop module 30 to achieve high-speed and high-precision correction of the light source module 10. Error correction signal U by differential amplifying unit 0 The two paths of differential signals are converted into two paths of differential signals, and the two paths of differential signals are subjected to time-sharing gating, so that the consistency of time delay of the two paths of differential signals is ensured, and the correction precision of the linear correction system of the photoelectric phase-locked loop is improved; at the same time, the error correction signal U is amplified by the differential amplifying unit 0 The system can be converted into two paths of differential signals, and the structure of the photoelectric phase-locked loop linear correction system can be optimized.
Specifically, in the present application, referring to fig. 1 and 2, the light source module 10, the photoelectric conversion module 20 and the phase-locked loop module 30 form a feedback loop, and the light source module 10 generates a laser beam according to the pre-correction signal. The photoelectric conversion module 20 converts one part of the laser beam into a probe beam, and the other part of the laser beam into a reference beam, and the ratio of the part of the laser beam converted into the reference beam to the part of the laser beam converted into the probe beam is 10:90. The photoelectric conversion module 20 receives the reference beam, converts the reference beam into a beat signal, and transmits the beat signal to the phase-locked loop module 30.
The phase-locked loop module 30 compares the frequency and phase of the beat signal with the frequency and phase of the reference signal after receiving the beat signal. Generating a phase discrimination signal according to the phase difference between the beat frequency electric signal and the reference signal, then identifying a burr signal in the phase discrimination signal according to the frequency difference between the phase discrimination signal and the reference signal, and filtering the burr signal to generate an error correction signal U 0 . Subsequently, the phase-locked loop module 30 corrects the error correction signal U 0 Converted into a first differential signal U with the same amplitude and opposite polarity 1 And a second differential signal U 2 Then to the first differential signal U 1 And a second differential signal U 2 Integrating to generate an error correction voltage signal U with positive and negative slopes d Then the error correction voltage signal U d Superimposed on the pre-correction signal to generate a modulated voltage signal U with correction information t The light source module 10 then receives the modulated voltage signal U t And according to the modulated voltage signal U t The emitted laser beam.
In one embodiment of the present application, the phase-locked loop module 30 includes a phase discrimination unit 31 and a signal processing unit 32. Wherein the phase detection unit 31 is electrically connected to the photoelectric conversion module 20, and is configured to receive the beat signal, generate a phase detection signal according to a phase difference between the beat signal and the reference signal, and filter a glitch signal in the phase detection signal to generate an error correction signal U 0 . The signal processing unit 32 is electrically connected to the phase detection unit 31 for receiving the error correction signal U 0 And error correction signal U 0 Converted into a modulated voltage signal U t 。
In particular, please refer to fig. 1 and fig2 in an embodiment of the application, the phase detection unit 31 comprises a phase detector 311 and a filter. The phase detector 311 is electrically connected to the photoelectric conversion module 20, and is configured to receive the beat signal, and output a phase detection signal according to a phase difference between the beat signal and the reference signal, so that the beat signal locks the phase of the reference signal. The filter is electrically connected to the phase detector 311 and the signal processing unit 32, and is configured to receive the phase detection signal and filter the glitch signal in the phase detection signal to generate an error correction signal U 0 Thereby making the error correction signal U 0 Is synchronized with the frequency of the reference signal.
In one embodiment of the present application, the signal processing unit 32 includes a differential amplifier 321, and the differential amplifier 321 is connected to the phase discrimination unit 31 for receiving the error correction signal U 0 And error correction signal U 0 Converting first differential signals U with same amplitude and opposite polarity 1 And a second differential signal U 2 。
Specifically, referring to fig. 1 and 2, in the implementation of the present application, the differential amplifier 321 is electrically connected to the loop filter 312 and is configured to receive the error correction signal U generated by the loop filter 312 0 And error correction signal U 0 Converted into a first differential signal U 1 And a second differential signal U 2 And time-sharing gating, wherein the first differential signal U 1 And a second differential signal U 2 Is the same in amplitude and opposite in polarity.
Error correction signal U is passed through differential amplifier 321 0 Converted into a first differential signal U with the same amplitude and opposite polarity 1 And a second differential signal U 2 And a first differential signal U 1 And a second differential signal U 2 Time-sharing gating ensures the first differential signal U 1 And a second differential signal U 2 The consistency of time delay is improved, so that the correction precision of the photoelectric phase-locked loop linear correction system is improved. At the same time, the error correction signal U is passed through the differential amplifier 321 0 Converted into a first differential signal U with the same amplitude and opposite polarity 1 And a second differential signal U 2 It is also possible to optimize the linearity correction system of the electro-optic phase-locked loopAnd (5) the structure of the system.
In one embodiment of the application, the signal processing unit 32 further comprises a direction selection unit 33. The direction selection unit 33 is electrically connected to the differential amplifier 321, the differential amplifier 321 has a first output terminal and a second output terminal, and the direction selection unit 33 has a first access point and a second access point. The direction selecting unit 33 is used for generating a first switching signal, and the direction selecting unit 33 gates the first access point and the first output terminal at a first time according to the first switching signal to make the first differential signal U 1 And outputting the first signal to a ground first access point through a first output end. The direction selecting unit 33 is further configured to generate a second switching signal, and the direction selecting unit 33 gates the second access point and the second output terminal at a second timing according to the second switching signal to enable the second differential signal U 2 And outputting the signal to the second access point through the second output end. Wherein the first timing sequence and the second timing sequence are alternately connected in turn.
Specifically, in the embodiment of the present application, referring to fig. 1 and 2, the direction selecting unit 33 includes a selecting switch 331 and a direction selecting controller 332. Wherein 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 the direction selection controller 332 is configured to generate a first switching signal at a first timing and a second switching signal at a second timing.
The direction selection controller 332 controls the selection switch 331 to gate the first access point and the first output terminal at the first timing through the first switching signal for the first differential signal U 1 Output from the first output terminal and pass through the first access point in a first time sequence. The direction selection controller 332 controls the selection switch 331 to gate the second access point and the second output terminal at the second timing sequence for the second differential signal U by the second switching signal 2 Output from the second output terminal and pass through the second access point in the second time sequence. Wherein the first time sequence and the second time sequence are alternately connected in turn, so that the change-over switch continuously outputs the first differential signal U 1 And a second differential signal U 2 。
In one embodiment of the application, the signal processing unit 32 further comprises an integrator 322. The integrator 322 is electrically connected to the selection switch 331.
In particular, in the implementation of the present application, please refer to fig. 1 and 2, due to the first differential signal U 1 And a second differential signal U 2 The first differential signal U is continuously output by the change-over switch 1 And a second differential signal U 2 The square wave signals are broken in each other, and the current signals for controlling the light source module 10 to generate the laser beams are triangular waves. Therefore, the integrator 322 is required to be used for the first differential signal U 1 And a second differential signal U 2 And (5) processing.
Error correction voltage signal U d The method comprises the steps of sequentially and alternately setting a first error correction voltage signal and a second error correction voltage signal along 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.
Integrator 322 is configured to receive a first differential signal U 1 And at a first timing sequence, the first differential signal U 1 Into a first error correction voltage signal having a positive slope. The integrator 322 is further configured to receive a second differential signal U 2 And at a second timing sequence, the second differential signal U 2 Into a second error correction voltage signal having a negative slope. And the integrator 322 is also used for converting the first error correction voltage signal and the second error correction voltage signal into a continuously output error correction voltage signal U d Wherein the timing sequence includes a first timing sequence and a second timing sequence.
Error correction voltage signal U d Corresponding error correction signal U of upper sweep frequency 0 The positive slope part of (a), the error correction voltage signal U d Corresponding error correction signal U of lower sweep frequency 0 Is included in the negative slope portion of (a). First differential signal U 1 Is positive in polarity, the second differential signal U 2 Is negative, the first differential signal U is provided at the integrator 322 1 And a second differential signal U 2 Converted into an error correction voltage signal U d After that, the first differential signal U 1 Corresponding error correction signal U 0 Upper sweep of (2) second differenceDivide signal U 2 Corresponding error correction signal U 0 Is used for the frequency sweep.
In one embodiment of the present 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 for generating a pre-correction signal. Adder 324 is electrically connected to integrator 322 and light source module 10 for adding the pre-correction signal and error correction voltage signal U d To form a modulated voltage signal U t . Wherein the waveform generator 323 generates a pre-correction signal as a synchronization trigger for the switching signal generated by the direction selection controller 332.
Specifically, in the embodiment of the present application, referring to fig. 1 and 2, the pre-correction signal includes a first pre-correction signal having a positive slope and a second pre-correction signal having a negative slope. The waveform generator 323 is electrically connected to the direction selection controller 332, and the adder 324 is electrically connected to the waveform generator 323, the integrator 322 and the light source module 10.
The waveform generator 323 generates a first pre-correction signal at a first timing and a second pre-correction signal at a second timing. And the waveform generator 323 controls the direction selection controller 332 to generate the first switching signal at a first timing by the first pre-correction signal, and controls the direction selection controller 332 to generate the second switching signal at a second timing by 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 at a first timing and the second pre-correction signal and the second error correction voltage signal at a second timing to generate modulated voltage signal U t And output.
The waveform generator 323 is added in the phase-locked loop module 30, and the waveform generator 323 generates a pre-correction signal by inputting a pre-correction parameter into the waveform generator 323, so that the phase difference between the beat frequency electric signal and the reference signal at the initial time is reduced, and the speed of locking the phase of the reference signal by the beat frequency electric signal is improved.
In one embodiment of the application, the lightThe source module 10 comprises a laser driver 11, a laser 12 and an optical coupler 13 and an optical interferometer 14. Wherein the laser driver 11 is electrically connected to the adder 324 and the laser 12 for modulating the voltage signal U t Generating a modulated current signal I t . The laser 12 is electrically connected to the laser driver 11, and the laser driver 11 modulates the current signal I according to t The excitation laser 12 emits a laser beam.
An optical coupler 13 is provided on an optical path of the laser beam for receiving the laser beam and splitting the laser beam into a probe beam and a reference beam, and an optical interferometer 14 is provided on an optical path of the reference beam for receiving the reference beam and converting the reference beam into a beat beam. The photoelectric conversion module 20 is disposed on the optical path of the beat frequency beam, and is configured to receive the beat frequency beam and convert the reference beam into a beat frequency signal.
Specifically, in the embodiment of the present application, referring to fig. 2 and 3, the optical interferometer 14 is a mach-zehnder interferometer, the photoelectric conversion module 20 is a balance detector 21, the reference beam is received by the balance detector 21, and the balance detector 21 is used to convert the reference beam into a beat signal.
An optical isolator 15 is provided between the optical interferometer 14 and the laser 12 for blocking the laser beam emitted from the laser 12 in the direction opposite to that of the laser beam. The optical interferometer 14 comprises in order a first coupler 141, a reference light path 142 and a second coupler 143, wherein the reference light path 142 is an optical fiber.
The optical interferometer 14, upon receiving the laser beam, the optical coupler splits the laser beam into a reference beam and a probe beam in a ratio of 10:90.
Wherein the probe beam irradiates on the object 50 to be measured, for measuring the distance between the object 50 to be measured and the linear correction system of the photoelectric phase-locked loop, and the reference beam irradiates on the optical interferometer 14. The reference light path 142 has two light paths for light beam conduction, the reference light beam is split into a long-wave beat frequency light beam and a short-wave beat frequency light beam by the first coupler 141 with a beam splitting ratio of 50:50, then the long-wave beat frequency light beam and the short-wave beat frequency light beam are respectively conducted by the two light paths, then the long-wave beat frequency light beam and the short-wave beat frequency light beam are output in the respective light paths through the second coupler 143 with a beam splitting ratio of 50:50 to generate beat frequency light beams, and the beat frequency light beams generate beat frequency signals on the photosensitive surface of the balance detector 21, so that the balance detector 21 outputs beat frequency electric signals.
On the other hand, the embodiment of the application provides a ranging device, which comprises the photoelectric phase-locked loop linearity correction system provided by the embodiment.
Compared with the prior art, the distance measuring device comprises the photoelectric phase-locked loop linear correction system provided by the embodiment, wherein the phase-locked loop module 30 in the photoelectric phase-locked loop linear device corrects the frequency and the phase of the beat signal by the frequency and the phase of the reference signal, and eliminates the high-frequency signal in the beat signal to generate the modulated voltage signal U with good linearity t The light source module 10 is made to respond to the modulated voltage signal U t The corresponding light source is emitted, so that the phase-locked loop module 30 realizes high-speed and high-precision correction of the light source module 10 to improve the measurement precision of the distance measuring device.
Specifically, referring to fig. 1 and 4, in the embodiment of the present application, an optical coupler in the linear correction system of the electro-optical phase-locked loop is disposed on an optical path of a laser beam, and is used for receiving the laser beam and splitting the laser beam into a probe beam and a reference beam, and the optical coupler is connected with a lens 40. The laser 12 employs a tunable laser 12 so that the frequency of the laser beam can be linearly modulated.
Wherein, by injecting a proper driving current into the tunable laser 12 to output a laser signal swept by a time linear triangular wave, the laser signal is divided into a reference beam and a probe beam by an optical coupler with a split ratio of 10:90 after passing through an isolator, the probe beam is emitted to free space by a lens 40 for irradiating an object 50 to be measured, and the reflected light of the probe beam is received by the lens 40 to determine the distance between the distance measuring device and the object 50 to be measured, and at the same time, the reference beam is converted into a beat beam by an optical interferometer 14, the beat beam is converted into a beat signal by a balance detector 21, and then the phase-locked loop module 30 is based on the phase and frequency of the reference signalRate correcting the phase and frequency of the beat signal to generate a modulated voltage signal U with good linearity t And will modulate the voltage signal U t To the light source module 10 so that the light source module 10 can modulate the voltage signal U according to the modulation voltage signal t The laser light source is emitted to realize the phase-locked loop module 30 to realize the high-speed and high-precision correction of the light source module 10.
The foregoing description of the preferred embodiments of the application is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the application.
Claims (10)
1. An electro-optic phase-locked loop linearity correction system, comprising:
the light source module is used for emitting laser beams according to the modulated voltage signals;
the photoelectric conversion module is arranged on the optical path of the laser beam 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 with the photoelectric conversion module and the light source module, and the phase-locked loop module, the light source module and the photoelectric conversion module form a feedback loop; the phase-locked loop module is used for receiving the beat frequency electric signal and correcting the phase and the frequency of the beat frequency electric signal according to the phase and the frequency of the reference signal so as to generate an error correction signal;
the phase-locked loop module is internally provided with a differential unit, the differential unit is used for receiving the error correction signal and converting the error correction signal into two paths of differential signals, and the phase-locked loop module time-sharing gates the two paths of differential signals and converts the two paths of differential signals into modulated voltage signals with positive and negative slopes.
2. The electro-optic phase-locked loop linearity correction system of claim 1, wherein said phase-locked loop module further comprises:
the phase discrimination unit is electrically connected with the photoelectric conversion module and the differential unit and is used for receiving the beat frequency electric signal, generating a phase discrimination signal according to the phase difference between the beat frequency electric signal and the reference signal, and filtering a high-frequency signal in the phase discrimination signal to generate the error correction signal;
the signal processing unit is electrically connected with the differential unit and the light source module and is used for receiving the differential signal and converting the differential signal into the modulation voltage signal.
3. The electro-optic phase locked loop linearity correction system of claim 2, wherein said phase discrimination unit includes:
the phase discriminator is electrically connected with the photoelectric conversion module and is used for receiving the beat frequency electric signal and outputting a phase discrimination signal according to the phase difference between the beat frequency electric signal and the reference signal;
the filter is electrically connected with the phase discriminator and the differential amplifying unit, and is used for receiving the phase discriminator signal and filtering burr signals in the phase discriminator signal to generate the error correction signal.
4. The electro-optic phase locked loop linearity correction system of claim 3, wherein said differential unit includes a differential amplifier, said differential amplifier being connected to said filter;
the differential amplifier is used for receiving the error correction signal and converting 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.
5. The system of claim 4, wherein the signal processing unit comprises a direction selection unit, the direction selection unit being electrically connected to the differential amplifier;
the differential amplifier is provided with a first output end and a second output end, and the direction selection unit is provided with a first access point and a second access point;
the direction selection unit is used for generating a first switching signal, and gating the first access point and the first output end at a first time sequence according to the first switching signal so that the first differential signal is output to the first access point from the first output end;
the direction selection unit is further configured to generate a second switching signal, and gate the second access point and the second output end at a second timing sequence according to the second switching signal, so that the second differential signal is output to the second access point from the second output end;
wherein the first timing sequence and the second timing sequence are alternately connected in turn.
6. The electro-optic phase locked loop linearity correction system of claim 5, wherein said direction selection unit includes:
a selection switch having the first access point and the second access point;
the direction selection controller is used for generating the first switching signal, gating the first access point and the first output end at the first time sequence according to the first switching signal, and generating the second switching signal, and gating the second access point and the second output end at the second time sequence according to the second switching signal.
7. The electro-optic phase locked loop linearity correction system of claim 6, wherein said signal processing unit further comprises an integrator, said integrator being electrically connected to said selector switch;
the integrator is configured to receive the first differential signal and convert the first differential signal into a first error correction voltage signal having a positive slope at the first timing;
the integrator is used for receiving the second differential signal and converting the second differential signal into a second error correction voltage signal with a negative slope at the second time sequence;
the integrator is further configured to convert the first error correction voltage signal and the second error correction voltage signal into continuously output error correction voltage signals;
the error correction voltage signal comprises a first error correction voltage signal and a second error correction voltage signal which are sequentially and alternately continuous along a time sequence, and the time sequence comprises the first time sequence and the second time sequence.
8. The electro-optic phase locked loop linearity correction system of claim 7, wherein said signal processing unit further comprises:
the waveform generator is electrically connected with the direction selection controller; the waveform generator is used for generating a first pre-correction signal with a positive slope and a second pre-correction signal with a negative slope, controlling the direction selection controller to generate the first switching signal according to the first pre-correction signal, and controlling the direction selection controller to generate the second switching signal according to the second pre-correction signal;
the adder is electrically connected with the waveform generator, the integrator and the light source module; the adder is configured to superimpose the first pre-correction signal and the first error correction voltage signal at the first timing, and to superimpose the second pre-correction signal and the second error correction voltage signal at a second timing to generate the modulated voltage signal.
9. The electro-optic phase locked loop linearity correction system of claim 8, wherein said light source module comprises:
a laser for emitting a laser beam;
the laser driver is electrically connected with the adder and the laser and is used for generating a modulation current signal according to the modulation voltage signal and exciting the laser to emit the laser beam according to the modulation current signal;
the optical coupler is arranged on the optical path of the laser beam and is used for receiving the laser beam and splitting the laser beam into a detection beam and a reference beam;
the optical interferometer is arranged on the optical path of the reference beam and is used for receiving the reference beam and converting the reference beam into a beat frequency beam;
the photoelectric conversion unit is arranged on the optical path of the beat frequency light beam and is used for receiving the beat frequency light beam and converting the reference light beam into the beat frequency electric signal.
10. A ranging apparatus, comprising: an electro-optical phase locked loop linearity correction system as claimed in any of claims 1 to 9.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210134112.0A CN116626655A (en) | 2022-02-14 | 2022-02-14 | Photoelectric phase-locked loop linearity correction system and distance measuring device |
| PCT/CN2023/088471 WO2023151706A1 (en) | 2022-02-14 | 2023-04-14 | Photoelectric phase-locked loop linear correction system, and ranging apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202210134112.0A CN116626655A (en) | 2022-02-14 | 2022-02-14 | Photoelectric phase-locked loop linearity correction system and distance measuring device |
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| CN202210134112.0A Pending CN116626655A (en) | 2022-02-14 | 2022-02-14 | Photoelectric phase-locked loop linearity correction system and distance measuring device |
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| US5289252A (en) * | 1992-12-08 | 1994-02-22 | Hughes Aircraft Company | Linear frequency modulation control for FM laser radar |
| CN104833380A (en) * | 2015-04-22 | 2015-08-12 | 江苏骏龙电力科技股份有限公司 | Light frequency scanning non-linear calibration system |
| US11119213B2 (en) * | 2019-02-27 | 2021-09-14 | Aeva, Inc. | Method for generating a linear chirp from a laser light source |
| CN111025268A (en) * | 2019-12-27 | 2020-04-17 | 北京航天计量测试技术研究所 | Frequency modulation continuous wave laser ranging nonlinear correction method, device and storage medium |
| WO2021155567A1 (en) * | 2020-02-07 | 2021-08-12 | 华为技术有限公司 | Frequency modulation nonlinear correction-based ranging method and related device |
| CN111404006B (en) * | 2020-03-20 | 2021-02-02 | 北京理工大学 | Noise suppression method based on phase continuous frequency sweeping fiber laser |
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