CN114050867B

CN114050867B - Signal compensation method, device, equipment and storage medium

Info

Publication number: CN114050867B
Application number: CN202210013750.7A
Authority: CN
Inventors: 刘德良; 蔡俊; 陈雄颖; 罗丁元; 刘振河; 李英乐; 谢金声; 陆志
Original assignee: Qualsen International Technologies Co Ltd
Current assignee: Qualsen International Technologies Co Ltd
Priority date: 2022-01-07
Filing date: 2022-01-07
Publication date: 2022-04-22
Anticipated expiration: 2042-01-07
Also published as: CN114050867A

Abstract

The invention relates to the technical field of optical fiber sensing, and discloses a signal compensation method, a signal compensation device, signal compensation equipment and a storage medium. The method comprises the following steps: obtaining backward scattering light in an optical cable to be detected, and converting the backward scattering light into a high-frequency electric signal; demodulating the high-frequency electric signal, and filtering the demodulated high-frequency electric signal to obtain a component signal group; estimating the imbalance value in the component signal group by adopting a preset imbalance estimation algorithm to obtain a compensation parameter; and performing signal compensation on the high-frequency electric signal based on the compensation parameter to obtain a compensation signal. The signal compensation is carried out on the signal to be analyzed returned in the optical cable detection, so that the environment parameter in the signal can be restored in a near-fidelity manner finally.

Description

Signal compensation method, device, equipment and storage medium

Technical Field

The present invention relates to the field of optical fiber sensing technologies, and in particular, to a signal compensation method, apparatus, device, and storage medium.

Background

With the continuous development of the optical fiber sensing technology, the optical fiber sensor has the advantages of light weight, electromagnetic interference resistance, high sensitivity, safety, reliability, corrosion resistance, strong multiplexing capability, long-distance distributed application and the like, so that the distributed application of the optical fiber sensor becomes a hotspot of research and engineering application in recent years, and related optical fiber sensing technology products are also widely applied. Such as in oil well temperature and pressure measurements, oil pipeline monitoring, well logging techniques, seismic wave monitoring, bridge and building monitoring, and the like.

At present, in a coherent detection system based on IQ quadrature demodulation and phase-sensitive optical time domain reflection, an optical signal is used as a carrier for reading external environment changes, a corresponding optical signal is input into an optical fiber, and the external environment changes by changing the parameters of the optical fiber to change the intensity, phase or polarization state of the input optical signal, so as to realize data acquisition and transmission. However, when the environmental parameters are extracted in the system demodulation, the environmental parameters are easily affected by external signals, and the extracted signals have errors caused by unbalance of phases and gains, so that the fidelity of the recovery of the extracted environmental parameters is affected. Especially, on the premise of higher requirement for accuracy of the detection data, the existing system cannot meet the requirement for high-precision restoration of the detection data, and the acquisition of the related environment parameter data is influenced.

Disclosure of Invention

The invention mainly aims to solve the problem that the existing phase-sensitive optical time domain reflection coherent detection system has distortion on the environment parameters extracted from the detection optical signals.

The invention provides a signal compensation method applied to a phase-sensitive optical time domain reflection coherent detection system in a first aspect, which is characterized by comprising the following steps: obtaining backward scattering light in an optical cable to be detected, and converting the backward scattering light into a high-frequency electric signal; demodulating the high-frequency electric signal, and filtering the demodulated high-frequency electric signal to obtain a component signal group; estimating the imbalance value in the component signal group by adopting a preset imbalance estimation algorithm to obtain a compensation parameter; and performing signal compensation on the high-frequency electric signal based on the compensation parameter to obtain a compensation signal.

Optionally, in a first implementation manner of the first aspect of the present invention, the component signal group includes an in-phase component signal and a quadrature component signal, and the demodulating the high-frequency electrical signal and performing filtering processing on the demodulated high-frequency electrical signal to obtain the component signal group includes: carrying out signal frequency conversion processing on the high-frequency electric signal to obtain a zero-frequency signal; obtaining a local oscillator signal generated by the phase sensitive optical time domain reflection coherent detection system, and performing signal mixing processing on the zero-frequency signal and the local oscillator signal to obtain a zero intermediate-frequency signal; and carrying out low-pass filtering processing on the zero intermediate frequency signal to obtain an in-phase component signal and an orthogonal component signal.

Optionally, in a second implementation manner of the first aspect of the present invention, the zero intermediate frequency signal includes a subband signal; the estimating the imbalance value in the component signal group by using a preset imbalance estimation algorithm to obtain a compensation parameter includes: calculating the sub-band phase and the unbalance gain of the in-phase component signal and the quadrature component signal by adopting a preset signal unbalance calculation formula; and calculating the compensation parameters of the high-frequency electric signal according to the sub-band phase and the unbalance degree gain of the in-phase component signal and the quadrature component signal.

Optionally, in a third implementation manner of the first aspect of the present invention, the calculating the subband phase and the imbalance gain of the in-phase component signal and the quadrature component signal by using a preset signal imbalance calculation formula includes: selecting the in-phase component signal as a reference component signal; calculating a subband phase offset and a subband gain offset of the orthogonal component signal relative to the reference component signal by using a preset signal imbalance calculation formula based on the reference component signal; and calculating the sub-band phase and the unbalance gain of the in-phase component signal and the orthogonal component signal according to the sub-band phase offset and the sub-band gain offset.

Optionally, in a fourth implementation manner of the first aspect of the present invention, the zero intermediate frequency signal includes at least two subband signals; the estimating the imbalance value in the component signal group by using a preset imbalance estimation algorithm to obtain a compensation parameter includes: carrying out unbalance compensation calculation on the in-phase component signal and the quadrature component signal in each subband signal by adopting a signal unbalance calculation formula to obtain the subband phase and the unbalance gain of the in-phase component signal and the quadrature component signal of each subband signal; sequencing the subband phase and the unbalance gain of each subband signal according to the order of monotone increasing of subband frequency to obtain a subband phase sequence and an unbalance gain sequence, and constructing a binary sequence based on the subband phase sequence and the unbalance gain sequence; dividing the binary group sequence into a plurality of binary groups, and calculating sub-band phase compensation vectors and unbalance degree gain compensation vectors of the binary groups; performing inverse Fourier transform on the subband phase sequence and the unbalancedness gain sequence according to the subband phase compensation vector and the unbalancedness gain compensation vector to obtain compensation coefficients of the subband phase and the unbalancedness gain; and calculating a compensation parameter based on the compensation coefficient, the subband phase and the unbalance gain.

Optionally, in a fifth implementation manner of the first aspect of the present invention, the calculating a subband phase compensation vector and an imbalance gain compensation vector of the binary packet includes: respectively calculating the maximum value of the phase difference and the maximum value of the gain difference of each binary group according to the sub-band phase and the imbalance gain in each binary group, and respectively judging whether the maximum value of the phase difference and the maximum value of the gain difference are smaller than a preset threshold value; if the maximum phase difference value is smaller than a preset corresponding threshold value, combining sub-band phases in the corresponding binary groups, and replacing a combined result with a preset first compensation value to obtain a sub-band phase compensation vector; and if the maximum gain difference value is smaller than a preset corresponding threshold value, combining the unbalanced gain corresponding to the binary groups, and replacing the combined result with a preset second compensation value to obtain an unbalanced gain compensation vector.

Optionally, in a sixth implementation manner of the first aspect of the present invention, the signal imbalance calculation formula is:

；

where I 'is a reference signal, w is the angular frequency of a component signal, t is time, Q' is a quadrature component signal, m is the subband gain offset of the quadrature component signal relative to the reference signal,

the subband phase offsets of the quadrature component signals relative to the reference signal.

A second aspect of the present invention provides a signal compensation apparatus, comprising: the conversion module is used for acquiring the backward scattering light in the optical cable to be detected and converting the backward scattering light into a high-frequency electric signal; the demodulation module is used for demodulating the high-frequency electric signal and filtering the demodulated high-frequency electric signal to obtain a component signal group; the estimation module is used for estimating an imbalance value in the component signal group by adopting a preset imbalance estimation algorithm to obtain a compensation parameter; and the compensation module is used for performing signal compensation on the high-frequency electric signal based on the compensation parameter to obtain a compensation signal.

Optionally, in a first implementation manner of the second aspect of the present invention, the demodulation module includes: the frequency conversion unit is used for carrying out signal frequency conversion processing on the high-frequency electric signal to obtain a zero-frequency signal; the frequency mixing unit is used for acquiring a local oscillator signal generated by the phase sensitive optical time domain reflection coherent detection system and performing signal frequency mixing processing on the zero-frequency signal and the local oscillator signal to obtain a zero intermediate-frequency signal; and the filtering unit is used for carrying out low-pass filtering processing on the zero intermediate frequency signal to obtain an in-phase component signal and an orthogonal component signal.

Optionally, in a second implementation manner of the second aspect of the present invention, the estimation module includes: the component calculation unit is used for calculating the subband phase and the unbalance gain of the in-phase component signal and the quadrature component signal by adopting a preset signal unbalance calculation formula; and the parameter calculation unit is used for calculating the compensation parameters of the high-frequency electric signal according to the subband phase and the unbalance gain of the in-phase component signal and the quadrature component signal.

Optionally, in a third implementation manner of the second aspect of the present invention, the component calculation unit includes: selecting the in-phase component signal as a reference component signal; calculating a subband phase offset and a subband gain offset of the orthogonal component signal relative to the reference component signal by using a preset signal imbalance calculation formula based on the reference component signal; and calculating the sub-band phase and the unbalance gain of the in-phase component signal and the orthogonal component signal according to the sub-band phase offset and the sub-band gain offset.

Optionally, in a fourth implementation manner of the second aspect of the present invention, the estimation module further includes: the component calculation unit is used for carrying out unbalance compensation calculation on the in-phase component signal and the quadrature component signal in each subband signal by adopting a signal unbalance calculation formula to obtain the subband phase and the unbalance gain of the in-phase component signal and the quadrature component signal of each subband signal; the ordering unit is used for ordering the subband phase and the unbalancedness gain of each subband signal according to the order of monotone increasing of the subband frequency to obtain a subband phase sequence and an unbalancedness gain sequence, and constructing a binary sequence based on the subband phase sequence and the unbalancedness gain sequence; the dividing unit is used for dividing the binary group sequence into a plurality of binary groups and calculating sub-band phase compensation vectors and unbalance degree gain compensation vectors of the binary groups; the integral transformation unit is used for carrying out Fourier inversion on the subband phase sequence and the unbalance gain sequence according to the subband phase compensation vector and the unbalance gain compensation vector to obtain compensation coefficients of the subband phase and the unbalance gain; and the parameter calculation unit is used for calculating a compensation parameter based on the compensation coefficient, the subband phase and the unbalance gain.

Optionally, in a fifth implementation manner of the second aspect of the present invention, the dividing unit includes: respectively calculating the maximum value of the phase difference and the maximum value of the gain difference of each binary group according to the sub-band phase and the imbalance gain in each binary group, and respectively judging whether the maximum value of the phase difference and the maximum value of the gain difference are smaller than a preset threshold value; if the maximum phase difference value is smaller than a preset corresponding threshold value, combining sub-band phases in the corresponding binary groups, and replacing a combined result with a preset first compensation value to obtain a sub-band phase compensation vector; and if the maximum gain difference value is smaller than a preset corresponding threshold value, combining the unbalanced gain corresponding to the binary groups, and replacing the combined result with a preset second compensation value to obtain an unbalanced gain compensation vector.

Optionally, in a sixth implementation manner of the second aspect of the present invention, the component calculation unit further includes: the signal imbalance calculation formula is as follows:

；

A third aspect of the present invention provides a signal compensation apparatus comprising: a memory and at least one processor, the memory having instructions stored therein; the at least one processor invokes the instructions in the memory to cause the signal compensation device to perform the various steps of the signal compensation method described above.

A fourth aspect of the present invention provides a computer-readable storage medium having stored therein instructions, which, when run on a computer, cause the computer to perform the steps of the signal compensation method described above.

According to the technical scheme provided by the invention, the backward scattering light in the optical cable to be detected is obtained and converted into a high-frequency electric signal; demodulating the high-frequency electric signal, and filtering the demodulated high-frequency electric signal to obtain a component signal group; estimating the imbalance value in the component signal group by adopting a preset imbalance estimation algorithm to obtain a compensation parameter; and performing signal compensation on the high-frequency electric signal based on the compensation parameter to obtain a compensation signal. Compared with the prior art, the method and the device have the advantages that the component signal group after demodulation and filtering is subjected to sub-band unbalance value estimation and combined multi-sub-band broadband unbalance value estimation, and the compensation parameters are calculated according to the corresponding estimation values, so that the compensation parameters are used for compensating the signals to be analyzed returned by the detection optical cable, and the compensation signals with high reduction fidelity on the environment parameters are obtained. The estimation and compensation of IQ imbalance in a phase-sensitive optical time domain reflection coherent detection system are realized, the method has the advantage of real-time compensation of signals to be analyzed, is wide in applicable scene, can search similar imbalance areas based on a coefficient array and combine the areas, further reduces the calculated amount and improves the efficiency of compensation calculation.

Drawings

FIG. 1 is a schematic diagram of a first embodiment of a signal compensation method according to an embodiment of the present invention;

FIG. 2 is a block diagram of a phase sensitive optical time domain reflectometry coherent detection system according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of an IQ quadrature distortion circuit model of a signal compensation method according to an embodiment of the present invention;

FIG. 4 is a flow chart of an imbalance estimation algorithm of the signal compensation method according to the embodiment of the present invention;

FIG. 5 is a diagram of a second embodiment of a signal compensation method according to an embodiment of the present invention;

FIG. 6 is a diagram of a third embodiment of a signal compensation method according to an embodiment of the present invention;

FIG. 7 is a flowchart illustrating IQ imbalance calculation of a signal compensation method according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of an embodiment of a signal compensation apparatus according to an embodiment of the present invention;

fig. 9 is a schematic diagram of another embodiment of a signal compensation device according to an embodiment of the present invention;

fig. 10 is a schematic diagram of an embodiment of a signal compensation device in an embodiment of the present invention.

Detailed Description

The embodiment of the invention provides a signal compensation method, a device, equipment and a storage medium, wherein the method comprises the following steps: obtaining backward scattering light in an optical cable to be detected, and converting the backward scattering light into a high-frequency electric signal; demodulating the high-frequency electric signal, and filtering the demodulated high-frequency electric signal to obtain a component signal group; estimating the imbalance value in the component signal group by adopting a preset imbalance estimation algorithm to obtain a compensation parameter; and performing signal compensation on the high-frequency electric signal based on the compensation parameter to obtain a compensation signal. The signal compensation is carried out on the signal to be analyzed returned in the optical cable detection, so that the environment parameter in the signal can be restored in a near-fidelity manner finally.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims, as well as in the drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that the embodiments described herein may be practiced otherwise than as specifically illustrated or described herein. Furthermore, the terms "comprises," "comprising," or "having," and any variations thereof, are intended to cover non-exclusive inclusions, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

For understanding, the following describes a specific flow of an embodiment of the present invention, and referring to fig. 1, a first embodiment of a signal compensation method according to an embodiment of the present invention includes:

101. obtaining the backward scattering light in the optical cable to be detected, and converting the backward scattering light into a high-frequency electric signal;

in the present embodiment, the backward scattering light refers to a method of determining the loss coefficient of the optical fiber by using the power of rayleigh scattering light in proportion to the power of transmitted light and by using the power of rayleigh scattering light in the opposite direction to the transmitted light, and is called a backward scattering method, and the corresponding backward scattering light is generated by transmitting a detection optical signal in a detection optical cable; the high frequency electrical signal herein refers to an electrical signal of a higher frequency (e.g., 200 MHz). By testing the optical fiber backscattering curve of the backward scattered light, the abnormal phenomena of whether the optical fiber attenuation on the optical cable line is uniformly distributed along the length direction, whether a micro-crack part exists on the whole length of the optical fiber, whether the optical fiber connection part is reliable or not, whether the abnormal phenomena exist or not, whether a non-joint part has a step or not and the like are found, and the detection of the target optical cable is realized. The phase-sensitive optical time domain reflection coherent detection system comprises an IQ quadrature demodulation circuit imbalance compensation required by optical sensing technologies such as DAS (distributed acoustic sensing system), DVS (distributed optical fiber vibration sensing system), OFDR (optical frequency domain reflection technology), BOTDR (optical time domain reflection), and the like, and is also applicable to the in-band gain fluctuation of a broadband hardware circuit and is also in the protection range of the application.

In practical application, a phase sensitive optical time domain reflection coherent detection system is adopted to perform optical cable detection on a target optical cable, and a narrow linewidth laser is used for generating a corresponding narrow linewidth continuous wave laser signal and outputting the signal to an optical coupler; the optical coupler divides the input narrow linewidth continuous wave laser signal into 2 paths for output, for example, the ratio is 1:9, 90% of power output is used as the output of a transmitting link to a pulse modulator, and 10% of power is used as a local oscillation optical signal to be output to a 2 x 2 coupler; the pulse modulator modulates the continuous optical signal input from the optical coupler into a pulse optical signal, improves the frequency of the pulse optical signal by 200MHz, and outputs the pulse optical signal to the erbium-doped optical fiber amplifier for optical power amplification; and then the pulse light signal after power amplification of the circulator is transmitted into the optical cable to be detected, and backward scattered light generated by a backward scattering method in the optical cable to be detected is received, namely the detection light signal and the backward scattered light are transmitted/received and separated, so that backward scattered light in the optical cable to be detected is obtained. And then, the backward scattered light output by the circulator and the local oscillator light signal from the optical coupler are subjected to optical interference by using a 2 x 2 coupler, and the resulting signal of the optical interference is subjected to photoelectric conversion and optical frequency mixing by using a double balanced detector (BPD), so that a high-frequency electric signal with a preset high frequency is obtained.

A schematic diagram of a frame of the phase-sensitive optical time-domain reflective coherent detection system is shown in fig. 2, and the phase-sensitive optical time-domain reflective coherent detection system includes a narrow-linewidth laser, an optical coupler, a pulse modulator array, an erbium-doped fiber amplifier, a circulator, a detection optical cable, a 2 × 2 coupler, a double-balanced detector, an IQ quadrature demodulator, a low-pass filter, an a/D converter, a signal processing unit, and the like.

102. Demodulating the high-frequency electric signal, and filtering the demodulated high-frequency electric signal to obtain a component signal group;

in this embodiment, the component signal group here refers to a signal composed of an in-phase component signal and a quadrature component signal; by adopting the IQ quadrature demodulator to directly shift the signal from the central frequency point W (MHz) (higher than high frequency) to the zero intermediate frequency baseband, the phase demodulation error caused by the clock frequency deviation between the hardware clock and the virtual clock of the signal processing unit can be avoided.

In practical application, 200MHz high-frequency electric signals carrying measurement signals obtained by processing of a double-balanced detector are demodulated and subjected to frequency conversion to obtain two paths of zero-frequency signals, local oscillation signals generated by a phase-sensitive optical time domain reflection coherent detection system are used, the zero-frequency signals and the local oscillation signals are subjected to signal frequency mixing processing to obtain zero intermediate-frequency signals, the obtained zero intermediate-frequency signals are subjected to low-pass filtering processing, and the signals obtained by the low-pass filtering processing are subjected to analog-to-digital conversion by using an A/D converter to obtain component signal groups.

Wherein, for the demodulation and filtering processing of the high-frequency electric signal, the corresponding IQ quadrature distortion circuit model is schematically shown in FIG. 3, including double balanceGain imbalance full link cumulant (gi, gq) and local frequency f of two branches of detector (BPD), branch circuit and I, Q₀The system comprises a zero intermediate frequency signal (X), a Low Pass Filter (LPF), an in-phase component signal (I), a quadrature component signal (Q) and an A/D converter.

103. Estimating the imbalance value in the component signal group by adopting a preset imbalance estimation algorithm to obtain a compensation parameter;

in this embodiment, the imbalance estimation algorithm is an algorithm that performs sub-band IQ imbalance estimation and joint multi-sub-band wideband IQ imbalance estimation processing on a component signal group to obtain compensation parameters of corresponding sub-band signals; the compensation parameters refer to phase imbalance full link accumulated values a of the I/Q two branches, and I, Q gain imbalance full link accumulated amounts gi and gq of the two branches. Assuming that the BPD output signal is X = cos (cos × pi × f × t), ideally, the corresponding I, Q value is:

；

in the case of IQ imbalance, the expression for I & Q will become as follows:

；

further, as gi and gq increase and a increase, the error of solving the signal phase B = arctan (Q/I) becomes larger, and particularly when the signal power is small (more influenced by an external signal), the error of the corresponding phase calculation value B fluctuates obviously. Based on the principle of a phase-sensitive optical time domain reflection coherent detection system, the phase information contained in the signal output by the BPD corresponds to the state of the external environment parameter, so that the phase error can bring direct influence on the extraction of the external environment parameter. Therefore, by taking a signal processing thought in wireless communication as a reference, aiming at the broadband characteristic of the frequency spectrum of the output signal of the double-balanced detector, the frequency correlation of IQ quadrature imbalance makes the processing defect that single coefficient cannot be adopted to realize imbalance compensation, so that a plurality of coefficients are adopted to form a coefficient vector, a zero intermediate frequency IQ digital signal output based on A/D adopts a two-stage algorithm to estimate a phase and gain calibration coefficient vector, and IQ imbalance compensation aiming at the A/D output signal is realized by using the compensation parameter obtained by processing.

In practical application, a component signal group obtained by processing the subband signals by using a preset imbalance estimation algorithm according to the number of the subband signals of the processed zero intermediate frequency signals is firstly subjected to subband phase and imbalance gain of in-phase component signals and quadrature component signals in the component signal group, then the subband phase and the imbalance gain are used for estimating the imbalance value of the subband signals by using the imbalance estimation algorithm, and then compensation parameters are calculated according to the imbalance estimation value.

The flowchart of the imbalance estimation algorithm is shown in fig. 4, and includes a/D converter, sub-band IQ imbalance estimation, joint multi-sub-band wideband IQ imbalance estimation, IQ imbalance compensation, and IQ calibrated signal composition.

104. And performing signal compensation on the high-frequency electric signal based on the compensation parameter to obtain a compensation signal.

In this embodiment, the compensation parameters obtained by processing are used to perform signal compensation on the zero intermediate frequency signal after the high-frequency electrical signal is processed, so as to obtain a compensation signal capable of performing high-fidelity restoration on the environmental parameters. The non-ideal characteristic of the IQ orthogonal demodulator, the accumulated non-ideal factors of each link between two paths of outputs of the IQ orthogonal demodulator and analog inputs of an A/D device can cause imbalance of phases and gains of two paths of signals (I & Q) after actual A/D conversion, an analysis result of errors during signal phase extraction is caused, compensation parameters obtained by processing and operation of an imbalance estimation algorithm are adopted, compensation processing of signals is carried out on the two paths of signals after A/D conversion, and then a signal processing unit is used for carrying out analysis processing on the compensated signals, so that high-fidelity restoration can be carried out on surrounding environment parameters of optical fibers contained in backward dispersed light, and a more accurate optical fiber detection analysis result is obtained.

In the embodiment of the invention, the backward scattering light in the optical cable to be detected is obtained and converted into a high-frequency electric signal; demodulating the high-frequency electric signal, and filtering the demodulated high-frequency electric signal to obtain a component signal group; estimating the imbalance value in the component signal group by adopting a preset imbalance estimation algorithm to obtain a compensation parameter; and performing signal compensation on the high-frequency electric signal based on the compensation parameter to obtain a compensation signal. Compared with the prior art, the method and the device have the advantages that the component signal group after demodulation and filtering is subjected to sub-band unbalance value estimation and combined multi-sub-band broadband unbalance value estimation, and the compensation parameters are calculated according to the corresponding estimation values, so that the compensation parameters are used for compensating the signals to be analyzed returned by the detection optical cable, and the compensation signals with high reduction fidelity on the environment parameters are obtained. The estimation and compensation of IQ imbalance in a phase-sensitive optical time domain reflection coherent detection system are realized, the method has the advantage of real-time compensation of signals to be analyzed, is wide in applicable scene, can search similar imbalance areas based on a coefficient array and combine the areas, further reduces the calculated amount and improves the efficiency of compensation calculation.

Referring to fig. 5, a second embodiment of the signal compensation method according to the embodiment of the present invention includes:

201. obtaining the backward scattering light in the optical cable to be detected, and converting the backward scattering light into a high-frequency electric signal;

202. carrying out signal frequency conversion processing on the high-frequency electric signal to obtain a zero-frequency signal;

in this embodiment, the frequency conversion processing refers to directly converting a high-frequency signal into a baseband signal without performing modulation and demodulation of an intermediate frequency; the high-frequency electric signal is subjected to frequency conversion processing of the signal by utilizing a zero intermediate frequency receiver architecture in an IQ quadrature demodulator, so that the high-frequency electric signal is converted into a required zero-frequency signal.

203. Acquiring a local oscillator signal generated by a phase sensitive optical time domain reflection coherent detection system, and performing signal mixing processing on the zero-frequency signal and the local oscillator signal to obtain a zero intermediate-frequency signal;

in this embodiment, the local oscillator signal refers to a local oscillator frequency, and in the phase-sensitive optical time domain reflection coherent detection system, there is a frequency generated by a corresponding LC oscillator unit, which is called a local oscillator frequency, and the local oscillator signal and the zero-frequency signal are demodulated by using a multiplexing correlation algorithm, so as to obtain a required zero intermediate frequency signal.

In practical application, the local oscillator signal generated by the phase sensitive optical time domain reflection coherent detection system is obtained, and then the zero-frequency signal and the obtained local oscillator signal are subjected to signal mixing processing, so that the required zero intermediate-frequency signal is obtained.

204. Carrying out low-pass filtering processing on the zero intermediate frequency signal to obtain an in-phase component signal and a quadrature component signal;

in this embodiment, the low-pass filtering processing refers to selecting a signal to be processed in a preset frequency range by using a low-pass filter in a phase-sensitive optical time domain reflection coherent detection system, so as to obtain a required low-pass signal to be processed, thereby implementing suppression of a near-end interference signal.

In practical applications, said set of component signals comprises an in-phase component signal and a quadrature component signal. And carrying out low-pass filtering processing on the zero intermediate frequency signal by using a low-pass filter in the phase-sensitive optical time domain reflection coherent detection system so as to obtain the required in-phase component signal and quadrature component signal.

205. Selecting the in-phase component signal as a reference component signal;

in this embodiment, when the zero intermediate frequency signal includes a subband signal, the in-phase component signal is selected as the reference component signal for calculating the compensation parameter. For IQ components of the same signal, there is a statistical cyclic symmetry property, in particular: the I component and the Q component are mutually orthogonal, namely the time integral of the product sum of the two components is a smaller value close to 0 (the time length has no fixed criterion and can be more than 4 times of the corresponding period of the minimum frequency); the power of the I component and the Q component is equal, namely the time integral values of the squares of the two components are almost equal (the time length has no fixed criterion and can be more than 4 times of the corresponding period of the minimum frequency); the in-phase component signal is selected as the reference component signal, and the calculation of the related parameters of the other component signal can be realized by utilizing the relation between the two components.

206. Calculating a subband phase offset and a subband gain offset of the orthogonal component signal relative to the reference component signal by using a preset signal imbalance calculation formula based on the reference component signal;

in this embodiment, the signal imbalance calculation formula refers to

；

Where I 'is the reference signal, w is the angular frequency of the component signal, t is time, Q' is the quadrature component signal, m is the subband gain offset of the quadrature component signal relative to the reference signal,

is the subband phase offset of the quadrature component signal relative to the reference signal. For the subband signals, the relative bandwidth is narrow, so the IQ imbalance can be approximately the same within the bandwidth, and therefore, for each subband, the actual IQ imbalance only needs to use one gain imbalance value and one phase imbalance value.

In practical applications, the subband phase offset and the subband gain offset of the quadrature component signal with respect to the reference component signal are calculated based on the reference component signal using a preset signal imbalance calculation formula, and the subband phase offset and the subband gain offset of the quadrature component signal with respect to the reference component signal are calculated using a signal imbalance calculation formula with the reference component signal I' = cos (w × t) and the ideal quadrature component signal Q = sin (w × t) in quadrature demodulation.

207. Calculating the sub-band phase and the unbalance gain of the in-phase component signal and the orthogonal component signal according to the sub-band phase offset and the sub-band gain offset;

in this embodiment, according to the subband phase offset and the subband gain offset obtained by processing, the current orthogonal component signal is compared with the ideal orthogonal signal to obtain the subband phase and the imbalance gain of the in-phase component signal and the orthogonal component signal.

208. Calculating compensation parameters of the high-frequency electric signal according to the sub-band phase and the unbalance gain of the in-phase component signal and the quadrature component signal;

in this embodiment, the subband phase and the imbalance gain are calculated and obtained by assuming x = tan ψ and y = 1/((1 + m) × cos ψ) according to the subband phase and the imbalance gain of the in-phase component signal and the quadrature component signal, and then the subsequent compensation for the IQ component signal can be realized by using the subband phase and the imbalance gain and using I = I ', Q = x × I ' + y × Q '.

209. And performing signal compensation on the high-frequency electric signal based on the compensation parameter to obtain a compensation signal.

In the embodiment of the invention, signal frequency conversion processing is carried out on the high-frequency electric signal to obtain a zero-frequency signal; acquiring a local oscillator signal generated by a phase sensitive optical time domain reflection coherent detection system, and performing signal mixing processing on the zero-frequency signal and the local oscillator signal to obtain a zero intermediate-frequency signal; and carrying out low-pass filtering processing on the zero intermediate frequency signal to obtain an in-phase component signal and a quadrature component signal. Calculating the sub-band phase and the unbalance gain of the in-phase component signal and the orthogonal component signal by adopting a preset signal unbalance calculation formula; and calculating the compensation parameters of the high-frequency electric signal according to the sub-band phase and the unbalance gain of the in-phase component signal and the quadrature component signal. Compared with the prior art, the in-phase component signal and the orthogonal component signal are obtained through IQ orthogonal demodulation processing, phase and gain imbalance estimation of each narrow sub-band in a frequency domain bandwidth is achieved based on the I/Q statistical cyclic symmetry characteristic, and compensation parameters corresponding to the sub-band phase and the imbalance gain are obtained. Therefore, IQ imbalance compensation vectors can be rapidly analyzed and solved, IQ imbalance rapid change under certain scenes is adapted, real-time compensation of signals to be compensated is achieved, and signals returned by optical cable detection with high fidelity are obtained.

Referring to fig. 6, a third embodiment of the signal compensation method according to the embodiment of the present invention includes:

301. obtaining the backward scattering light in the optical cable to be detected, and converting the backward scattering light into a high-frequency electric signal;

302. demodulating the high-frequency electric signal, and filtering the demodulated high-frequency electric signal to obtain a component signal group;

303. carrying out unbalance compensation calculation on the in-phase component signal and the orthogonal component signal in each subband signal by adopting a signal unbalance calculation formula to obtain the subband phase and unbalance gain of the in-phase component signal and the orthogonal component signal of each subband signal;

in this embodiment, the zero intermediate frequency signal includes at least two subband signals, and the in-phase component signal and the quadrature component signal in each subband signal are subjected to imbalance compensation calculation by using a signal imbalance calculation formula, so as to obtain the subband phase and the imbalance gain of the in-phase component signal and the quadrature component signal of each subband signal.

304. Sequencing the subband phase and the unbalancedness gain of each subband signal according to the monotonically increasing order of the subband frequency to obtain a subband phase sequence and an unbalancedness gain sequence, and constructing a binary sequence based on the subband phase sequence and the unbalancedness gain sequence;

in this embodiment, the binary group here refers to one tuple per row and another tuple per column. In a two-dimensional table, tuples are also referred to as rows, by forming a sequence of tuples from a plurality of tuples.

In practical application, based on the obtained subband phase and the unbalancedness gain of the plurality of subbands, sequencing the subband phase and the unbalancedness gain according to the monotone increasing sequence of the subband frequency to obtain a corresponding subband phase sequence and an unbalancedness gain sequence; and then constructing a binary sequence based on the subband phase sequence and the imbalance gain sequence. Wherein, assuming that the length of the x and y sequences is K, corresponding to K narrow sub-bands, corresponding x_m、y_mForming a doublet, thus obtaining a doublet sequence: [ x ] of_m，y_m]Wherein m is more than or equal to 1 and less than or equal to K.

305. Respectively calculating the maximum value of the phase difference and the maximum value of the gain difference of each binary group according to the phases of the sub-bands and the gain of the imbalance degree in each binary group, and respectively judging whether the maximum value of the phase difference and the maximum value of the gain difference are smaller than a preset threshold value;

in this embodiment, the binary sequence is divided into a plurality of binary groups according to the number of preset tuple elements, and then the maximum value of the phase difference and the maximum value of the gain difference of each binary group are respectively calculated according to the subband phase and the imbalance gain in each binary group, and whether the maximum value of the phase difference and the maximum value of the gain difference are smaller than a preset threshold value is respectively determined. For example, the tuple sequence is sequentially divided into a plurality of groups, each group comprising 6 tuples; the maximum value of the phase difference between the components corresponding to each tuple in the group is calculated, and if the maximum value of the phase difference between the components corresponding to each tuple in the group is smaller than the threshold T (T can be set in practical application, and is set to 0.1 in this example).

306. If the maximum phase difference value is smaller than a preset corresponding threshold value, combining the sub-band phases in the corresponding binary groups, and replacing a combined result with a preset first compensation value to obtain a sub-band phase compensation vector;

in this embodiment, the first compensation value refers to a compensation value uniformly set in advance or an average value of components of tuples in a group; and according to the result of judging whether the maximum value of the phase difference and the maximum value of the gain difference are smaller than a preset threshold value, if the maximum value of the phase difference is smaller than a preset corresponding threshold value, combining the sub-band phases in the corresponding binary groups, and replacing the combined result with a preset first compensation value to obtain a sub-band phase compensation vector. For example, if the maximum value of the phase difference is smaller than the preset corresponding threshold, the 6 tuples in each group are combined, i.e. 6 adjacent subbands are combined and replaced by the preset first compensation value.

307. If the maximum value of the gain difference is smaller than a preset corresponding threshold value, combining the gain of the imbalance degree in the corresponding binary groups, and replacing the combined result with a preset second compensation value to obtain a compensation vector of the gain of the imbalance degree;

in this embodiment, according to the result of determining whether the maximum value of the phase difference and the maximum value of the gain difference are smaller than the preset threshold, if the maximum value of the gain difference is smaller than the preset corresponding threshold, combining the imbalance gains in the corresponding binary groups, and replacing the combined result with the preset second compensation value, thereby obtaining the imbalance gain compensation vector.

308. Carrying out Fourier inversion on the subband phase sequence and the unbalance gain sequence according to the subband phase compensation vector and the unbalance gain compensation vector to obtain compensation coefficients of subband phase and unbalance gain;

in this embodiment, according to the processed subband phase compensation vector and the imbalance gain compensation vector, inverse fourier transform processing is performed on the subband phase sequence and the imbalance gain sequence, so as to obtain a compensation coefficient of the subband phase and the imbalance gain, where the compensation coefficient is a coefficient array.

309. Calculating a compensation parameter based on the compensation coefficient, the sub-band phase and the unbalance gain;

in this embodiment, the compensation parameter is calculated based on the calculated compensation coefficient, the subband phase, and the imbalance gain.

310. And performing signal compensation on the high-frequency electric signal based on the compensation parameter to obtain a compensation signal.

In this embodiment, the IQ imbalance calculation flowchart based on multi-subband signals, as shown in fig. 7, includes an in-phase component input signal (in-phase component signal), a quadrature component input signal (quadrature component signal), compensation parameters (compensation parameter 1, compensation parameter 2), and IQ calibrated signals (in-phase component output signal and quadrature component output signal); and multiplying and filtering the in-phase component signal and the orthogonal component signal by using the processed compensation parameters, and further obtaining a compensation signal which can restore the environmental parameters in a high fidelity manner through signal compensation processing.

In the embodiment of the invention, a signal imbalance calculation formula is adopted to carry out imbalance compensation calculation on the in-phase component signal and the quadrature component signal in each sub-band signal, so as to obtain the sub-band phase and the imbalance gain of the in-phase component signal and the quadrature component signal of each sub-band signal; sequencing the subband phase and the unbalancedness gain of each subband signal according to the monotonically increasing order of the subband frequency to obtain a subband phase sequence and an unbalancedness gain sequence, and constructing a binary sequence based on the subband phase sequence and the unbalancedness gain sequence; dividing the binary group sequence into a plurality of binary groups, and calculating sub-band phase compensation vectors and unbalance degree gain compensation vectors of the binary groups; carrying out Fourier inversion on the subband phase sequence and the unbalance gain sequence according to the subband phase compensation vector and the unbalance gain compensation vector to obtain compensation coefficients of subband phase and unbalance gain; and calculating a compensation parameter based on the compensation coefficient, the subband phase and the unbalance gain. Compared with the prior art, the compensation parameters are obtained by performing compensation calculation, grouping and parameter calculation processing on the multi-subband signals, so that flexible coefficient vector size cutting can be performed based on the characteristic of unbalanced frequency distribution of different board cards, better compromise between cost and performance is realized, the signals to be compensated can be compensated in real time, and the signals returned by the optical cable detection with high fidelity are obtained.

With reference to fig. 8, the signal compensation method in the embodiment of the present invention is described above, and a signal compensation apparatus in the embodiment of the present invention is described below, where an embodiment of the signal compensation apparatus in the embodiment of the present invention includes:

the conversion module 401 is configured to acquire backscattered light in an optical cable to be tested, and convert the backscattered light into a high-frequency electrical signal;

a demodulation module 402, configured to demodulate the high-frequency electrical signal and filter the demodulated high-frequency electrical signal to obtain a component signal group;

an estimation module 403, configured to estimate an imbalance value in the component signal group by using a preset imbalance estimation algorithm to obtain a compensation parameter;

and a compensation module 404, configured to perform signal compensation on the high-frequency electrical signal based on the compensation parameter to obtain a compensation signal.

Referring to fig. 9, another embodiment of the signal compensation apparatus according to the embodiment of the present invention includes:

Further, the demodulation module 402 includes:

the frequency conversion unit 4021 is configured to perform signal frequency conversion processing on the high-frequency electrical signal to obtain a zero-frequency signal;

the frequency mixing unit 4022 is configured to acquire a local oscillator signal generated by the phase-sensitive optical time domain reflection coherent detection system, and perform signal frequency mixing processing on the zero-frequency signal and the local oscillator signal to obtain a zero intermediate-frequency signal;

the filtering unit 4023 is configured to perform low-pass filtering on the zero intermediate frequency signal to obtain an in-phase component signal and an orthogonal component signal.

Further, the estimation module 403 includes:

a component calculating unit 4031, configured to calculate subband phases and imbalance gains of the in-phase component signal and the quadrature component signal by using a preset signal imbalance calculation formula;

a parameter calculating unit 4032, configured to calculate a compensation parameter of the high-frequency electrical signal according to the subband phase and the imbalance gain of the in-phase component signal and the quadrature component signal.

Further, the component calculation unit 4031 includes:

selecting the in-phase component signal as a reference component signal; calculating a subband phase offset and a subband gain offset of the orthogonal component signal relative to the reference component signal by using a preset signal imbalance calculation formula based on the reference component signal; and calculating the sub-band phase and the unbalance gain of the in-phase component signal and the orthogonal component signal according to the sub-band phase offset and the sub-band gain offset.

Further, the estimation module 403 further includes:

a component calculating unit 4033, configured to perform imbalance compensation calculation on the in-phase component signal and the quadrature component signal in each of the subband signals by using a signal imbalance calculation formula, so as to obtain a subband phase and an imbalance gain of the in-phase component signal and the quadrature component signal of each of the subband signals;

a sorting unit 4034, configured to sort the subband phase and the imbalance gain of each subband signal according to a monotonically increasing order of subband frequencies to obtain a subband phase sequence and an imbalance gain sequence, and construct a binary sequence based on the subband phase sequence and the imbalance gain sequence;

a dividing unit 4035, configured to divide the binary sequence into a plurality of binary groups, and calculate a subband phase compensation vector and an imbalance gain compensation vector of the binary group;

an integral transform unit 4036, configured to perform inverse fourier transform on the subband phase sequence and the unbalancedness gain sequence according to the subband phase compensation vector and the unbalancedness gain compensation vector, to obtain compensation coefficients of the subband phase and the unbalancedness gain;

a parameter calculating unit 4037, configured to calculate a compensation parameter based on the compensation coefficient, the subband phase, and the imbalance gain.

Further, the dividing unit 4035 includes:

respectively calculating the maximum value of the phase difference and the maximum value of the gain difference of each binary group according to the sub-band phase and the imbalance gain in each binary group, and respectively judging whether the maximum value of the phase difference and the maximum value of the gain difference are smaller than a preset threshold value; if the maximum phase difference value is smaller than a preset corresponding threshold value, combining sub-band phases in the corresponding binary groups, and replacing a combined result with a preset first compensation value to obtain a sub-band phase compensation vector; and if the maximum gain difference value is smaller than a preset corresponding threshold value, combining the unbalanced gain corresponding to the binary groups, and replacing the combined result with a preset second compensation value to obtain an unbalanced gain compensation vector.

Further, the component calculation unit 4031 or the component calculation unit 4033 further includes:

the signal imbalance calculation formula is as follows:

；

where I' is the reference signal, w is the angular frequency of the component signal, and t isTime, Q' is the quadrature component signal, m is the subband gain offset of the quadrature component signal relative to the reference signal,

In the embodiment of the invention, IQ imbalance estimation between the output of a double-balance detector and the sampling of an A/D converter is realized by adopting two-stage coefficient vector estimation, so that rapid analysis and solving of IQ imbalance compensation vectors can be realized, and the fast IQ imbalance estimation method is suitable for rapid change of IQ imbalance under certain scenes; the combination of similar unbalance degree areas is realized based on coefficient array search, the calculated amount of IQ unbalance compensation is reduced on the premise of no obvious performance influence, the real-time compensation of the signal to be compensated is realized, and the signal returned by the optical cable detection with high fidelity is obtained.

Fig. 8 and 9 describe the signal compensation apparatus in the embodiment of the present invention in detail from the perspective of the modular functional entity, and the signal compensation apparatus in the embodiment of the present invention is described in detail from the perspective of hardware processing.

Fig. 10 is a schematic structural diagram of a signal compensation apparatus 500 according to an embodiment of the present invention, where the signal compensation apparatus 500 may have a relatively large difference due to different configurations or performances, and may include one or more processors (CPUs) 510 (e.g., one or more processors) and a memory 520, and one or more storage media 530 (e.g., one or more mass storage devices) for storing applications 533 or data 532. Memory 520 and storage media 530 may be, among other things, transient or persistent storage. The program stored in the storage medium 530 may include one or more modules (not shown), each of which may include a series of instructions operating on the signal compensation device 500. Still further, the processor 510 may be configured to communicate with the storage medium 530 to execute a series of instruction operations in the storage medium 530 on the signal compensation device 500.

The signal compensation apparatus 500 may also include one or more power supplies 540, one or more wired or wireless network interfaces 550, one or more input-output interfaces 560, and/or one or more operating systems 531, such as Windows Server, Mac OS X, Unix, Linux, FreeBSD, and the like. Those skilled in the art will appreciate that the signal compensation device configuration shown in fig. 10 does not constitute a limitation of the signal compensation device and may include more or fewer components than those shown, or some components may be combined, or a different arrangement of components.

The present invention also provides a signal compensation device, which includes a memory and a processor, wherein the memory stores computer readable instructions, and the computer readable instructions, when executed by the processor, cause the processor to execute the steps of the signal compensation method in the above embodiments.

The present invention also provides a computer-readable storage medium, which may be a non-volatile computer-readable storage medium, and which may also be a volatile computer-readable storage medium, having stored therein instructions, which, when executed on a computer, cause the computer to perform the steps of the signal compensation method.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a read-only memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

The application is operational with numerous general purpose or special purpose computing system environments or configurations. For example: personal computers, server computers, hand-held or portable devices, tablet-type devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like. The application may be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The application may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A signal compensation method is applied to a phase-sensitive optical time domain reflection coherent detection system, and is characterized by comprising the following steps:

obtaining backward scattering light in an optical cable to be detected, and carrying out optical frequency mixing and photoelectric conversion processing on the backward scattering light to obtain a high-frequency electric signal with a preset high frequency;

demodulating the high-frequency electric signal to obtain a zero intermediate frequency signal, and filtering the zero intermediate frequency signal to obtain a component signal group, wherein the component signal group comprises an in-phase component signal and an orthogonal component signal;

carrying out unbalance compensation calculation on the in-phase component signal and the quadrature component signal of each corresponding subband signal in the zero intermediate frequency signal by adopting a signal unbalance calculation formula to obtain the subband phase and the unbalance gain of the in-phase component signal and the quadrature component signal of each subband signal;

sequencing the subband phase and the unbalance gain of each subband signal according to the order of monotone increasing of subband frequency to obtain a subband phase sequence and an unbalance gain sequence, and constructing a binary sequence based on the subband phase sequence and the unbalance gain sequence;

dividing the binary group sequence into a plurality of binary groups, and calculating sub-band phase compensation vectors and unbalance degree gain compensation vectors of the binary groups;

performing inverse Fourier transform on the subband phase sequence and the unbalancedness gain sequence according to the subband phase compensation vector and the unbalancedness gain compensation vector to obtain compensation coefficients of the subband phase and the unbalancedness gain;

calculating a compensation parameter based on the compensation coefficient, the subband phase and the unbalance gain;

and performing signal compensation on the high-frequency electric signal based on the compensation parameter to obtain a compensation signal.

2. The signal compensation method of claim 1, wherein the demodulating the high-frequency electrical signal and filtering the demodulated high-frequency electrical signal to obtain a component signal group comprises:

carrying out signal frequency conversion processing on the high-frequency electric signal to obtain a zero-frequency signal;

obtaining a local oscillator signal generated by the phase sensitive optical time domain reflection coherent detection system, and performing signal mixing processing on the zero-frequency signal and the local oscillator signal to obtain a zero intermediate-frequency signal;

and carrying out low-pass filtering processing on the zero intermediate frequency signal to obtain an in-phase component signal and an orthogonal component signal.

3. The signal compensation method of claim 1, wherein the calculating the subband phase compensation vector and the imbalance gain compensation vector for the binary group comprises:

respectively calculating the maximum value of the phase difference and the maximum value of the gain difference of each binary group according to the sub-band phase and the imbalance gain in each binary group, and respectively judging whether the maximum value of the phase difference and the maximum value of the gain difference are smaller than a preset threshold value;

if the maximum phase difference value is smaller than a preset corresponding threshold value, combining sub-band phases in the corresponding binary groups, and replacing a combined result with a preset first compensation value to obtain a sub-band phase compensation vector;

and if the maximum gain difference value is smaller than a preset corresponding threshold value, combining the unbalanced gain corresponding to the binary groups, and replacing the combined result with a preset second compensation value to obtain an unbalanced gain compensation vector.

4. The signal compensation method of claim 1, wherein the signal imbalance calculation formula is:

；

5. A signal compensation apparatus, characterized in that the signal compensation apparatus comprises:

the conversion module is used for acquiring the backward scattering light in the optical cable to be detected, and carrying out optical frequency mixing and photoelectric conversion processing on the backward scattering light to obtain a high-frequency electric signal with a preset high frequency;

the demodulation module is used for demodulating the high-frequency electric signal to obtain a zero intermediate frequency signal, and filtering the zero intermediate frequency signal to obtain a component signal group, wherein the component signal group comprises an in-phase component signal and an orthogonal component signal;

the estimation module is used for carrying out unbalance compensation calculation on the in-phase component signal and the quadrature component signal of each corresponding subband signal in the zero intermediate frequency signal by adopting a signal unbalance calculation formula to obtain the subband phase and the unbalance gain of the in-phase component signal and the quadrature component signal of each subband signal; sequencing the subband phase and the unbalance gain of each subband signal according to the order of monotone increasing of subband frequency to obtain a subband phase sequence and an unbalance gain sequence, and constructing a binary sequence based on the subband phase sequence and the unbalance gain sequence; dividing the binary group sequence into a plurality of binary groups, and calculating sub-band phase compensation vectors and unbalance degree gain compensation vectors of the binary groups; performing inverse Fourier transform on the subband phase sequence and the unbalancedness gain sequence according to the subband phase compensation vector and the unbalancedness gain compensation vector to obtain compensation coefficients of the subband phase and the unbalancedness gain; calculating a compensation parameter based on the compensation coefficient, the subband phase and the unbalance gain;

and the compensation module is used for performing signal compensation on the high-frequency electric signal based on the compensation parameter to obtain a compensation signal.

6. A signal compensation apparatus, characterized in that the signal compensation apparatus comprises: a memory and at least one processor, the memory having instructions stored therein;

the at least one processor invokes the instructions in the memory to cause the signal compensation device to perform the steps of the signal compensation method of any of claims 1-4.

7. A computer-readable storage medium having instructions stored thereon, which when executed by a processor implement the steps of the signal compensation method according to any one of claims 1-4.