Frequency drift compensation system and method based on phase carrier modulation, program, equipment and storage medium

Abstract

The invention provides a frequency drift compensation system and method based on phase carrier modulation, a program, equipment and a storage medium, the phase modulation depth of an auxiliary interferometer is combined with the peak-to-peak value of a modulation signal of a laser, and the phase modulation depth of the auxiliary interferometer can be updated when the target object of the interferometer is measured to move. The method is suitable for large-dynamic-range displacement measurement; based on the phase drift amount caused by drifting of the center frequency of the laser and obtained by the auxiliary interferometer, an error signal is obtained by comparing a real-time phase demodulation value of the auxiliary interferometer with an initial phase demodulation value, the center frequency of the laser is controlled, and it can be guaranteed that the output center frequency of the laser is stable; the influence of direct current offset, unequal amplitude and non-orthogonal errors on the demodulation result of the measurement interferometer is eliminated through the peak detection corrector, and the nonlinear error of the demodulation result of the measurement interferometer is effectively reduced. The method is low in calculation complexity and good in system compatibility, and can be widely applied to a high-precision optical fiber displacement measurement system.

Description

Technical Field

[0001] This invention belongs to the field of fiber optic interferometer phase demodulation technology, specifically relating to a frequency drift compensation system, method, program, device, and storage medium based on phase carrier modulation. Background Technology

[0002] Displacement, as a fundamental physical quantity, has significant applications in gravitational wave detection, precision manufacturing, drag-free satellite control, and geophysical exploration. Breakthroughs in displacement sensing technology have not only enabled precise measurement of sub-nanometer displacements but also provided innovative solutions for the coupled measurement of multiple physical quantities. Through electromechanical conversion mechanisms, dynamic changes in physical quantities such as pressure, velocity, and acceleration can be transformed into displacement quantities for characterization and measurement, greatly expanding the application dimensions of displacement sensors. Fiber optic displacement sensors have attracted widespread attention due to their inherent advantages, such as low cost, small footprint, fast response speed, high sensitivity, and resistance to electromagnetic interference.

[0003] In interferometric measurement systems, the choice of phase demodulation technique directly affects the fidelity of signal reconstruction and the robustness of the system. Currently, mainstream phase demodulation methods include digital IQ demodulation, the 3×3 coupler method, and phase-generated carrier (PGC) demodulation. Among these, PGC demodulation has been widely used in fiber optic sensing systems due to its advantages such as simple structure, high sensitivity, wide dynamic range, and good linearity. Classical PGC demodulation methods typically include differential cross-multiplication (PGC-DCM) and arctangent (PGC-Arctan). PGC-DCM demodulation is directly affected by optical interference, carrier phase delay, the non-ideal performance of the low-pass filter, and the drift of the phase modulation depth C, leading to nonlinear distortion in the demodulation results. The later-proposed PGC-Arctan demodulation method can eliminate the influence of optical interference; however, other factors such as carrier phase delay and the drift of the phase modulation depth C still contribute to nonlinear distortion. When the target object moves, the C value changes accordingly. When the C value deviates from 2.63 rad, the PGC-Arctan demodulation method will produce severe harmonic distortion. Previous studies have shown that the carrier phase delay can be derived and calculated mathematically, thus achieving compensation. Applying peak detection correction methods can achieve real-time correction of periodic nonlinear errors, thereby obtaining accurate demodulation results. Furthermore, when the target object moves, the peak-to-peak value of the laser modulation signal can be controlled by PID control, thereby changing the laser's tuning range and stabilizing the C value around 2.63 rad, enabling large dynamic range displacement measurement.

[0004] The laser center frequency is the measurement reference for fiber optic displacement sensors, determining their measurement accuracy. Currently, laser frequency stabilization techniques include phase-locked loop (PLL) technology, external cavity feedback technology, absorption line frequency locking technology, and offset frequency locking technology. These techniques are difficult to apply to interferometric measurement systems with cost and size constraints; therefore, using an auxiliary reference interferometer to compensate for the impact of frequency drift on demodulation results remains essential. For demodulation systems, eliminating the impact of laser center frequency drift on demodulation results at low cost is of great significance and practical value. Summary of the Invention

[0005] The purpose of this invention is to provide a frequency drift compensation system, method, program, device, and storage medium based on phase carrier modulation, which can be used for displacement measurement with a large dynamic range. It uses an auxiliary interferometer to obtain the influence of laser center frequency drift on demodulation results, and then controls the DC quantity of the laser modulation signal to ensure the stability of the laser center frequency, thereby significantly reducing the influence of frequency drift on demodulation results.

[0006] A frequency drift compensation system based on phase carrier modulation includes a light source module and a swept frequency interference optical path module. The swept frequency interference optical path module includes a first coupler, an optical fiber circulator, an optical fiber probe, and a reference interferometer. The optical signal output by the light source module is split into two paths after passing through the first coupler. One path passes through the optical fiber circulator and is transmitted to the target object through the optical fiber probe. The other path is input to the reference interferometer.

[0007] Furthermore, the light source module includes a laser and an optical fiber isolator, the optical fiber isolator being used to protect the optical signal output by the laser from unidirectional transmission.

[0008] Furthermore, the reference interferometer includes a second coupler and a third coupler. The second coupler splits the input optical signal into two paths: one path is transmitted to the third coupler through a normal line, and the other path is transmitted to the third coupler through an optical fiber delay line.

[0009] Furthermore, it also includes a photoelectric detection module, a laser modulator, and a data acquisition unit; the photoelectric detection module is used to convert optical signals into electrical signals, the laser modulator is used to generate the modulation signal of the laser, and the data acquisition unit is used to acquire the reference signal output by the reference interferometer, as well as the signal reflected back to the fiber optic circulator by the target object, that is, the displacement measurement signal between the target object and the fiber optic probe.

[0010] A method for frequency drift compensation based on phase carrier modulation includes the following steps:

[0011] Step 1: Initialize the modulation signal of the laser, including the DC component and the sinusoidal component;

[0012] Step 2: The laser outputs an optical signal, and the reference signal output by the reference interferometer is acquired. The reference signal is then mixed with the fundamental frequency carrier and the second harmonic carrier in the laser's modulation signal, respectively. High-frequency components are filtered out by a low-pass filter, and correction is performed to obtain two orthogonal signals. and ; Calculate the phase noise caused by the laser center frequency drift. ;

[0013]

[0014] Step 3: Adjust the DC component of the laser modulation signal, and repeat Step 2 until the calculated phase noise is obtained. If the value is less than the threshold, frequency drift compensation is achieved.

[0015] At this point, the displacement measurement signal between the target object and the fiber optic probe is acquired; the displacement measurement signal is then mixed with the fundamental frequency carrier and the second harmonic carrier in the modulation signal of the laser, respectively. High-frequency components are filtered out by a low-pass filter and corrected to obtain two orthogonal signals. and ; Calculate the phase demodulation result after frequency drift compensation ;

[0016]

[0017] Step 4: Based on the phase demodulation results after frequency drift compensation Calculate the displacement measurement results between the target object and the fiber optic probe. ;

[0018]

[0019] In the formula, The center wavelength of the laser output by the laser. denoted as the refractive index of the medium.

[0020] Furthermore, the reference signal is mixed with the fundamental frequency carrier and the second harmonic carrier of the laser's modulation signal, respectively, and the high-frequency components are filtered out by a low-pass filter to obtain two non-strictly orthogonal signals. and ;

[0021] For two non-strictly orthogonal signals and The specific method for correction is as follows:

[0022] Based on the sinusoidal component of the laser modulation signal Calculate the phase modulation depth of the reference interferometer Thus we obtain and The ratio between Furthermore, for two non-strictly orthogonal signals and The correction is performed to obtain two orthogonal signals. and :

[0023]

[0024]

[0025] Furthermore, the displacement measurement signal is mixed with the fundamental frequency carrier and the second harmonic carrier of the laser modulation signal, respectively, and the high-frequency components are filtered out by a low-pass filter to obtain two non-strictly orthogonal signals. and ;

[0026] For two non-strictly orthogonal signals and The correction was performed using a peak detection correction method:

[0027]

[0028] .

[0029] A computer device includes a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the frequency drift compensation method based on phase carrier modulation described above.

[0030] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the frequency drift compensation method based on phase carrier modulation described above.

[0031] A computer program product includes computer instructions that, when executed by a processor, implement the steps of the frequency drift compensation method based on phase carrier modulation described above.

[0032] The beneficial effects of this invention are as follows:

[0033] This invention combines the phase modulation depth of an auxiliary interferometer with the peak-to-peak value of the laser modulation signal. The phase modulation depth of the auxiliary interferometer is updated as the target object moves during interferometry measurement, making it suitable for displacement measurements with a large dynamic range. Based on the phase drift caused by laser center frequency drift obtained from the auxiliary interferometer, an error signal is obtained by comparing the real-time phase demodulation value of the auxiliary interferometer with the initial phase demodulation value, and the laser center frequency is controlled to ensure the stability of the laser output center frequency. A peak detection corrector eliminates the influence of DC offset, unequal amplitude, and non-orthogonal errors on the demodulation results of the measurement interferometer, effectively reducing the nonlinear errors in the demodulation results. This invention has low computational complexity, good system compatibility, and can be widely applied in high-precision fiber optic displacement measurement systems. Attached Figure Description

[0034] Figure 1 This is a device system block diagram of a frequency drift compensation method based on phase carrier modulation in this invention.

[0035] Figure 2 This is a diagram of the optical path of a frequency drift compensation system based on phase carrier modulation in this invention.

[0036] Figure 3 This is a graph showing the displacement demodulation results of a measurement interferometer without frequency drift compensation.

[0037] Figure 4 This is a graph showing the displacement demodulation results of the interferometer after frequency drift compensation.

[0038] Figure 5 This is a graph showing the displacement demodulation result of the reference interferometer after frequency drift compensation. Detailed Implementation

[0039] The present invention will now be further described with reference to the accompanying drawings.

[0040] like Figure 2 As shown, the present invention provides a frequency drift compensation system based on phase carrier modulation, comprising:

[0041] The photoelectric detection module 20 is used to convert optical signals into electrical signals;

[0042] Light source module 21: Laser 211, fiber optic isolator 212

[0043] Frequency sweeping interferometric optical path module 22: first coupler 221, fiber optic circulator 222, fiber optic probe 223, reference interferometer; the reference interferometer includes second coupler 224, fiber optic delay line 225 and third coupler 226;

[0044] Signal acquisition and processing module 23: laser modulator 232, computer 234, data acquisition unit 236;

[0045] Lines 231, 233, 235, and 237 are all data transmission lines;

[0046] The optical signal output by the laser 211 is split into two paths after passing through the fiber optic isolator 212 and the first coupler 221. One path passes through the fiber optic circulator 222 and is transmitted to the target object through the fiber optic probe 223. The target object reflects the optical signal back to the fiber optic circulator 222. The other path is input to the reference interferometer.

[0047] A frequency drift compensation method based on phase carrier modulation includes the following steps:

[0048] Step 1: Initialize the modulation signal of laser 211, including the DC component. Sine component ;

[0049] Step 2: Laser 211 outputs an optical signal to acquire the reference signal output by the reference interferometer. , reference signal The signals are mixed with the fundamental frequency carrier and the second harmonic carrier in the modulation signal of laser 211, respectively, and the high-frequency components are filtered out by a low-pass filter to obtain two non-strictly orthogonal signals. and ;

[0050] Based on the sinusoidal component of the modulation signal of laser 211 Calculate the phase modulation depth of the reference interferometer Thus we obtain and The ratio between Furthermore, for two non-strictly orthogonal signals and The correction is performed to obtain two orthogonal signals. and :

[0051]

[0052]

[0053] Calculate the phase noise caused by the center frequency drift of laser 211 ;

[0054]

[0055] Step 3: Adjust the DC component of the modulation signal of laser 211 using a PID controller. Repeat step 2 until the calculated phase noise is obtained. Less than the threshold, i.e. To achieve frequency drift compensation;

[0056] At this time, the signal reflected back to the fiber optic circulator 222 by the target object is acquired, which is the displacement measurement signal between the target object and the fiber optic probe 223. ; Displacement measurement signal The signals are mixed with the fundamental frequency carrier and the second harmonic carrier in the modulation signal of laser 211, respectively, and the high-frequency components are filtered out by a low-pass filter to obtain two non-strictly orthogonal signals. and ;

[0057] A peak detection correction method is used for two non-strictly orthogonal signals. and The correction is performed to obtain two orthogonal signals. and ;

[0058]

[0059]

[0060] Based on two orthogonal signals and Calculate the phase demodulation result after frequency drift compensation. ;

[0061]

[0062] Multiplying the phase demodulation result above by the phase-displacement coefficient yields the displacement demodulation result after frequency drift compensation. :

[0063]

[0064] In the formula, The center wavelength of the laser output by the laser. denoted as the refractive index of the medium.

[0065] Example 1:

[0066] like Figure 1 As shown, a frequency drift compensation system based on phase carrier modulation includes a signal modulation module 10, a phase demodulation module 11, a reference interferometer phase demodulation module 12, a measurement result calculation module 13, and a frequency drift compensation module 14.

[0067] The signal modulation module 10 includes a data acquisition module 102 and a modulation output module 103. The data acquisition module 102 is used to acquire the measurement interferometer interference signal and the reference interferometer interference signal output by the interferometer. After photoelectric conversion, the interference signal is converted from an optical signal into an electrical signal. The modulation output module 103 outputs a sine wave to the laser modulator 231 to modulate the laser 211. The modulated light is injected into the interferometer 22. The modulation frequency is set in the range of 1 kHz to 100 kHz to ensure a certain measurement speed.

[0068] The phase demodulation module 11 of the measurement interferometer sends the signal of the modulation output 103 to the first multiplier 112, then to the first frequency multiplier 111, and finally to the second multiplier 113. The outputs of the first multiplier 112 and the second multiplier 113 are then sent to the first low-pass filter 114 and the second low-pass filter 115, respectively. The cutoff frequency of the low-pass filter is selected between 0.5 kHz and 50 kHz according to the carrier signal frequency. The signals output from the first low-pass filter 114 and the second low-pass filter 115 are then sent to the peak detection corrector 116, and the corrected signal is sent to the first arctangent 117 to obtain the phase to be measured.

[0069] The reference interferometer phase demodulation module 12 sends the signal from the modulation output 103 to the third multiplier 122, then to the second frequency multiplier 121, and finally to the fourth multiplier 123. The outputs of the third multiplier 122 and the fourth multiplier 123 are then sent to the third low-pass filter 124 and the fourth low-pass filter 125, respectively. The cutoff frequency of the low-pass filter is selected between 0.5 kHz and 50 kHz according to the carrier signal frequency. Finally, the signals output from the third low-pass filter 124 and the fourth low-pass filter 125 are sent to the second arctangent 126 to obtain the phase to be measured.

[0070] The measurement result calculation module 13 sends the phase to be measured obtained from the first arctangent 117 into the fifth multiplier 131 and multiplies it with the phase-displacement coefficient to obtain the displacement demodulation result 133.

[0071] The frequency drift compensation module 14 sends the phase drift amount caused by the laser center frequency drift obtained by the second inverse cutter 126 to the PID controller 141. Based on the comparison between the real-time phase demodulation value in the second inverse cutter 126 and the initial phase demodulation value, the error signal is obtained and the laser center frequency is controlled by PID to ensure the stability of the laser output center frequency.

[0072] After filtering out the DC component and normalizing the AC component of the interference signal obtained by the detector, the measured signals of the measuring interferometer and the reference interferometer are respectively... and .

[0073]

[0074]

[0075] in, To measure the phase modulation depth of the interferometer, For reference interferometer phase modulation depth, The phase change caused by the displacement of the target object.

[0076] The interference signals from the measuring interferometer and the reference interferometer are independent of each other. Taking the measuring interferometer as an example, the interference signal is independent of the fundamental frequency carrier. and second harmonic carrier Multiply them separately. Then, pass them through two low-pass filters to remove high-frequency signals, obtaining a pair of non-strictly orthogonal components. and .

[0077]

[0078]

[0079] Reference interferometer signal By processing in the same way, a pair of non-strictly orthogonal components can also be obtained. and .

[0080]

[0081]

[0082] in, , and , These are the first and second order Bessel functions, respectively. The signals exhibit some amplitude variation, which affects the accuracy of the demodulation results. This error needs to be eliminated using a peak detection correction method. The reference interferometer does not require measuring a large dynamic range of displacement, therefore, the peak detection correction method was not used. The signal after interferometer correction was measured. and It can be represented as:

[0083]

[0084] Typically, the phase modulation depth is generated by the modulation source. The relationship between the phase modulation depth and the frequency modulation range and the working distance of the measuring interferometer is as follows:

[0085]

[0086] in, To measure the refractive index of the medium, The working distance of the interferometer, The frequency modulation range of the laser. The relevant modulation coefficients for the current corresponding to the laser output frequency modulation range. The amplitude of the applied signal. When At that time, the corresponding phase modulation depth The value is 2.630. In actual measurement, the target object moves the corresponding working distance of the interferometer. The amplitude of the modulated signal voltage can be changed by PID control, thereby altering the amplitude of the signal applied to the laser. This makes the phase modulation depth The value stabilized around 2.630.

[0087] The result of comparing the two orthogonal components of the measuring interferometer and the reference interferometer, and then applying the arctangent function, can be expressed as:

[0088]

[0089]

[0090] The phase noise caused by the center frequency drift of the laser can be expressed as:

[0091]

[0092]

[0093] in, The center wavelength of the laser. This represents the random drift of the laser's center wavelength. To measure the refractive index of the spatial optical path environment in the interferometer, To measure the working distance of the interferometer, To reference the arm length difference of the interferometer, The refractive index of the fiber in the reference interferometer is considered. In the designed scheme, light from the same laser has the same refractive index in different interferometers. . and These are the phase noise generated by the laser center frequency drift in the measuring interferometer and the reference interferometer, respectively.

[0094] The output wavelength of the laser after applying the modulation signal is:

[0095]

[0096] in, The effective refractive index of the medium inside the cavity. The piezoelectric coefficient of lead zirconate titanate (PZT) is... The order of the longitudinal modulus (integer). The DC component in the modulated signal. This refers to the sinusoidal component in the modulated signal.

[0097] The laser output center wavelength is:

[0098]

[0099] The DC component in the modulation signal is controlled by PID control. , making This ensures the stability of the laser's output center frequency. Correspondingly, the phase noise of the measurement interferometer and reference interferometer caused by the laser's center frequency drift... , The phase demodulation result of the measurement interferometer after frequency drift compensation can be expressed as:

[0100]

[0101] Multiplying the above phase demodulation result by the phase-displacement coefficient yields the displacement demodulation result of the measurement interferometer after frequency drift compensation.

[0102] Measurement compensation device such as Figure 2 As shown, the component selection and parameters of the interferometer measurement device are as follows:

[0103] (1) Laser 211 is a tunable external cavity semiconductor laser with a center wavelength of 1550 nm and an output power of 15 mW;

[0104] (2) The fiber optic isolator 212 operates at a wavelength of 1550 nm ± 5 nm, with an insertion loss ≤ 1.0 dB and a return loss ≥ 55 dB;

[0105] (3) Coupler 1 221 has a center wavelength of 1550 nm and a splitting ratio of 90% / 10%; Coupler 2 224 has a center wavelength of 1550 nm and a splitting ratio of 50% / 50%; Coupler 3 226 has a center wavelength of 1550 nm and a splitting ratio of 50% / 50%.

[0106] (4) Fiber circulator 222 center wavelength 1550 nm, insertion loss ≤1.0 dB, return loss ≥55 dB;

[0107] (5) Fiber optic probe 223 is a custom fiber optic probe with a center wavelength of 1550 nm;

[0108] (6) The photoelectric detection module 20 is an integrated photoelectric detector, which has four photoelectric detectors. The connection mode is fiber optic FC / APC, the working wavelength is 900 nm~1700 nm, the light intensity responsivity R=0.9 A / W, and the common mode rejection ratio ≥25dB.

[0109] (7) The data acquisition module 237 is an NI-USB-6353 acquisition card with a sampling rate of 1.25 MS / s and a sampling clock that is the internal clock of the acquisition card;

[0110] like Figure 3 As shown, the displacement demodulation result of the measurement interferometer without frequency drift compensation is 70.9 nm within 60 s due to the drift of the laser center frequency.

[0111] like Figure 4 As shown, the demodulation result of the interferometer displacement after frequency drift compensation is stable within 20 nm.

[0112] like Figure 5 As shown, the demodulation result of the reference interferometer displacement after frequency drift compensation is stable within 2 nm.

[0113] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A frequency drift compensation system based on phase carrier modulation, characterized in that: It includes a light source module (21) and a frequency sweeping interference optical path module (22). The frequency sweeping interference optical path module (22) includes a first coupler (221), an optical fiber circulator (222), an optical fiber probe (223), and a reference interferometer. The optical signal output by the light source module (21) is split into two paths after passing through the first coupler (221). One path passes through the optical fiber circulator (222) and is transmitted to the target object through the optical fiber probe (223). The other path is input to the reference interferometer.

2. The frequency drift compensation system based on phase carrier modulation according to claim 1, characterized in that: The light source module (21) includes a laser (211) and an optical fiber isolator (212). The optical fiber isolator (212) is used to protect the optical signal output by the laser (211) from unidirectional transmission.

3. The frequency drift compensation system based on phase carrier modulation according to claim 1, characterized in that: The reference interferometer includes a second coupler (224) and a third coupler (226). The second coupler (224) splits the input optical signal into two paths: one path is transmitted to the third coupler (226) through a normal line, and the other path is transmitted to the third coupler (226) through an optical fiber delay line (225).

4. The frequency drift compensation system based on phase carrier modulation according to claim 1, characterized in that: It also includes a photoelectric detection module (20), a laser modulator (232), and a data acquisition unit (236); the photoelectric detection module (20) is used to convert optical signals into electrical signals, the laser modulator (232) is used to generate the modulation signal of the laser (211), and the data acquisition unit (236) is used to acquire the reference signal output by the reference interferometer and the signal reflected back to the fiber optic circulator (222) by the target object, that is, the displacement measurement signal between the target object and the fiber optic probe (223).

5. A method for frequency drift compensation based on the phase carrier modulation-based system as described in claim 1, characterized in that: Step 1: Initialize the modulation signal of the laser (211), including the DC component and the sinusoidal component; Step 2: The laser (211) outputs an optical signal, and the reference signal output by the reference interferometer is obtained. The reference signal is mixed with the fundamental frequency carrier and the second harmonic carrier in the modulation signal of the laser (211) respectively. The high-frequency components are filtered out by a low-pass filter and corrected to obtain two orthogonal signals. and ; Calculate the phase noise caused by the center frequency drift of the laser (211). ; Step 3: Adjust the DC component of the modulation signal of the laser (211), and repeat Step 2 until the calculated phase noise is obtained. If the value is less than the threshold, frequency drift compensation is achieved. At this time, the displacement measurement signal between the target object and the fiber optic probe (223) is acquired; the displacement measurement signal is mixed with the fundamental frequency carrier and the second harmonic carrier in the modulation signal of the laser (211), the high frequency components are filtered out by a low-pass filter, and the signal is corrected to obtain two orthogonal signals. and ; Calculate the phase demodulation result after frequency drift compensation. ; Step 4: Based on the phase demodulation results after frequency drift compensation Calculate the displacement measurement results between the target object and the fiber optic probe (223). ; In the formula, The center wavelength of the laser output by the laser (211) is... denoted as the refractive index of the medium.

6. The frequency drift compensation method based on phase carrier modulation according to claim 5, characterized in that: The reference signal is mixed with the fundamental frequency carrier and the second harmonic carrier in the modulation signal of the laser (211), and the high-frequency components are filtered out by a low-pass filter to obtain two non-strictly orthogonal signals. and ; For two non-strictly orthogonal signals and The specific method for correction is as follows: Based on the sinusoidal component of the modulation signal of the laser (211) Calculate the phase modulation depth of the reference interferometer Thus we obtain and The ratio between Furthermore, for two non-strictly orthogonal signals and The correction is performed to obtain two orthogonal signals. and : 。 7. The frequency drift compensation method based on phase carrier modulation according to claim 5, characterized in that: The displacement measurement signal is mixed with the fundamental frequency carrier and the second harmonic carrier in the modulation signal of the laser (211), and the high-frequency components are filtered out by a low-pass filter to obtain two non-strictly orthogonal signals. and ; For two non-strictly orthogonal signals and The correction was performed using a peak detection correction method: 。 8. A computer device, comprising a memory, a processor, and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When executed by a processor, the computer program implements the steps of the method according to any one of claims 1 to 7.

10. A computer program product comprising computer instructions, characterized in that: When executed by a processor, the computer instructions implement the steps of the method according to any one of claims 1 to 7.

Images