65 results about "Phase sensitive" patented technology

The invention discloses a phi-OTDR (Optical Time Domain Reflectometer) vibration signal classification method based on multi-scale residual convolution and a bidirectional long-short-term memory network, relates to the technical field of phase-sensitive optical time domain reflectometer vibration sensing, and solves the problems of insufficient feature extraction, single model fusion mechanism, poor system real-time performance and the like of an existing phi-OTDR vibration signal classification method. The method is realized through the steps of a multi-scale deep convolutional network, a bidirectional long-short term memory network, a cross attention fusion module, a learnable gating mechanism and the like. A cross attention fusion module is adopted, association between spatial features and time sequence features is dynamically established in a double-path network, feature interaction and information coupling are deepened, and the sensing ability of the model to key information is remarkably improved. Meanwhile, the fusion proportion of the multi-path features is adaptively adjusted according to the actual distribution of the input features, background noise interference is effectively suppressed, and the robustness and discrimination performance of the model are enhanced. Accurate identification and classification of external vibration signals are realized.

The invention provides a phase-sensitive optical time domain reflectometer system and method, and the system comprises a first polarization-maintaining coupler which is used for dividing laser generated by a DC laser, and obtaining first laser and second laser; the optical fiber measurement front-end module is used for processing the random signal through pulse shaping and multi-carrier modulation technologies to generate an electric signal, and sequentially performing modulation, amplification, Rayleigh scattering and amplification on the first laser after the electric signal is generated to obtain amplified Rayleigh backscattered light; the second polarization-maintaining coupler is used for dividing the second laser to obtain third laser and local oscillation light; the delay optical fiber is used for processing the third laser to obtain delay light; the third polarization-maintaining coupler is used for combining the delayed light and the amplified Rayleigh backscattered light to obtain combined light; the receiver is used for processing the combined light and the local oscillation light to obtain multiple paths of target electric signals; and the oscilloscope is used for processing multiple paths of target electric signals through low-pass and high-pass filters and a phase noise compensation algorithm so as to determine power and phase distribution. The system cost can be reduced.

The invention discloses a composite hose structure for fuel gas transmission, and relates to the technical field of fuel gas transmission and distribution equipment, the composite hose structure comprises a dual-mode quick sealing assembly, dual-mode monitoring is formed by an FBG sensor, a phase-sensitive optical time domain reflectometer and a carbon tube composite filament, the FBG sensor can capture fine strain of a reinforced fiber layer in real time, and the phase-sensitive optical time domain reflectometer can capture the fine strain of the reinforced fiber layer in real time; the phase-sensitive optical time domain reflectometer detects and captures stress waves generated by crack propagation in a material through broadband sound waves, early recognition of millimeter-level damage in a pipe is achieved, grids woven by carbon tube composite filaments are utilized, continuity of the grids is monitored in real time through alternating-current impedance measurement, and the detection accuracy of the millimeter-level damage in the pipe is improved. When local grid resistance is increased due to breakage of the reinforced fiber layer, a micro-damage area can be accurately positioned, when leakage occurs, the memory alloy spring receives an electric signal monitored by a dual-mode, then axial thrust is generated to push the outer side of the fluororubber sealing ring, the fluororubber sealing ring expands in the radial direction under the thrust action of the memory alloy spring, and the leakage is prevented. And rapid and effective mechanical hard sealing is realized.

The application provides a phase-sensitive optical time domain reflectometer, a measurement method and a readable storage medium, wherein a signal generation circuit of the phase-sensitive optical time domain reflectometer is configured to generate a radio frequency signal to drive an optical intensity modulator to modulate probe light, so that two groups of frequency division multiplexing sequences with differences can be used to synchronously detect a sensing optical fiber to be measured, a differential unfolding algorithm is combined to accurately solve a phase change amount in adjacent sampling intervals, and then demodulation results corresponding to different frequency parts are respectively unfolded to obtain unfolded phase results, so that the problem of large strain phase folding is solved and a large strain range is recovered, and further, the unfolded phase results are rearranged and combined in time sequence through time sequence interleaving processing of the unfolded phase results, so that a high sampling rate and a distortion-free reconstruction result are reconstructed, and therefore, the application can realize accurate measurement of high frequency response and large strain range dynamic strain.

The application discloses a phase-sensitive pre-amplification method based on an electro-absorption modulated laser, and is applied to a star-ground laser communication system receiving end. A distributed feedback laser in the electro-absorption modulated laser amplifies weak pump light after long distance transmission, and generates idler light under the nonlinear effect of a laser cavity; an electro-absorption modulator in the electro-absorption modulated laser detects phase error information between signal light, pump light and idler light, and constructs an optical injection phase-locked loop through a feedback loop, so that stable control of the three-wave phase relationship is realized. Under the phase stability condition, the output light of the electro-absorption modulated laser is fed into a later-stage nonlinear medium to complete phase-sensitive pre-amplification. The phase-sensitive pre-amplification method based on the electro-absorption modulated laser has the advantages of simple structure and easy integration, can realize pump light amplification, idler light generation and phase error suppression under the condition of weak pump light, and effectively improves the receiving sensitivity performance of the star-ground laser communication system.

The invention discloses a carrier roller fault diagnosis method and system based on coupled vibration analysis, and the method specifically comprises the steps: separating a phase-sensitive optical time domain reflection signal based on a physical parameter of a conveying system, separating the phase-sensitive optical time domain reflection signal into a direct vibration signal and a conveying belt conduction vibration signal, recording the direct vibration signal as a first frequency band signal, and recording the second frequency band signal as a second frequency band signal; recording the conveying belt conduction vibration signal as a second frequency band signal; calculating a feature vector of the first frequency band signal to obtain a first feature vector set; calculating a feature vector of the second frequency band signal to obtain a second feature vector set; and carrying out feature fusion on the first feature vector set and the second feature vector set, and obtaining probability distribution of fault categories based on fused features. According to the method, the physical phenomenon of'conveying belt-carrier roller coupling vibration 'is systematically utilized for the first time, the defects that an existing method is single in dimension and prone to being interfered are overcome through double-channel feature fusion analysis, and the accuracy and robustness of early fault diagnosis of the carrier roller of the long-distance belt conveyor are remarkably improved.

The invention relates to the technical field of capacitance detection circuits, in particular to a capacitance digital conversion circuit based on phase-sensitive integration. The circuit comprises a phase shift circuit unit, a capacitance detection unit, a phase control unit and a digital processing unit. According to the invention, an excitation signal is converted into an excitation signal which is 90 degrees ahead by using a phase shift circuit through a phase shift circuit unit, a capacitance detection unit controls a single-pole double-throw switch S1 to alternately access the excitation signal and an inversion signal to a to-be-detected capacitor Cx and a reference capacitor C0, and a phase control unit utilizes integration-deintegration double stages in an integration stage. Phase signals are converted into high and low levels through a comparator so as to control overturning of a capacitor CF pole plate, the digital processing unit carries out phase sampling counting at 0 degree and 180 degrees, the capacitance value is calculated according to the ratio of the number of integration cycles to the number of deintegration half cycles, the influence of stray capacitance is reduced, and the measurement precision is improved.

An electromagnetic induction (EMI) system for characterizing geophysical (e.g. subterranean) environments, includes: (a) a transmitter module including a transmission coil and signal transmission electronics; and (b) at least one receiver module including a receiver coil and signal reception electronics wherein the at least one receiver module is physically separated from the transmitter module without a wired signal connection between them, wherein phase information of signals sent by the transmitter module and those received by at least one receiver module are preserved such that phase information of received signals may be determined and used in characterizing the geophysical environment. In some systems, signal preservation uses a pair of correlated, stable, high frequency clocks.

The invention relates to the technical field of light atmosphere, and discloses a light atmosphere effect generation method, which comprises the following steps: generating an initial wave function according to an intensity field, deducing on the basis of a potential energy field to obtain a first wave function, performing intensity calculation and phase extraction from the first wave function to obtain a second wave function, updating the direction field based on the second wave function to obtain an updated direction field and an enhanced optical flow field; three core advantages of light atmosphere generation are realized, firstly, deep coupling of quantum optics and neurocognition is realized, real response of human eyes is simulated through a phase-sensitive light response model, and light atmosphere distribution is enabled to conform to quantum propagation rules and human visual cognition characteristics in combination with a cognition attention focusing mechanism of a DQN model; and 2, a dynamic self-adaptive mechanism runs through the whole process, and a light current coefficient and object motion data are adjusted in real time through the pupil diameter to feed back a new light flow field so as to ensure that the environment change can be quickly responded.

This optical transmission system comprises: a phase conjugate conversion device (200) that performs optical parametric amplification in a first optical parametric amplification unit (238) and in a second optical parametric amplification unit (244), monitors electric power of a first polarized component and a second polarized component of first pilot light, controls the phase of higher harmonic wave excitation light by means of phase shifters (218, 224) so as to maximize the optical power of first pilot light to thereby synchronize the phase of the higher harmonic wave and the first pilot light, and controls a phase shifter (264) disposed in at least one path so as to maximize interference waveforms of respective components of second pilot light, which is different from the first pilot light in terms of the wavelength or the optical power and which has passed through from a pilot light source (270) in a reverse direction, to thereby match the optical length of the path of the first optical parametric amplification unit (238) and the path of the second optical parametric amplification unit (244); and a phase sensitive amplification device (400) for performing phase sensitive amplification on idler light and on an optical signal included in an optical transmission signal through optical parametric amplification using the excitation light controlled by using the first pilot light included in the optical transmission signal.

In the present invention, a second harmonic generator (103) generates pump light and local oscillator light from input light that is input to a second input section (102). A first demultiplexer (104) demultiplexes the pump light and the local oscillator light generated by the second harmonic generator (103). A combiner (105) combines the pump light demultiplexed by the first demultiplexer (104) with measurement light, and an amplifier (106) inputs the pump light and the measurement light combined by the combiner (105) and amplifies the measurement light through optical phase-sensitive amplification. An interferometer (108) causes 50 / 50 interference between the local oscillator light demultiplexed by the first demultiplexer (104) and the measurement light demultiplexed by a second demultiplexer (107).

The application discloses a kind of multi-modal partial discharge signal's adaptive filtering and intelligent separation method, and the application is related to power equipment insulation state monitoring and signal processing technical field, comprising the following steps: step S1: real-time acquisition power equipment partial discharge signal, and synchronously obtain equipment operating parameter and environmental noise signal.The multi-modal partial discharge signal's adaptive filtering and intelligent separation method, by dynamic coupling degree modeling and the synergistic mechanism of double-channel confrontation type decoupling, effectively solves the mode aliasing and feature distortion problem caused by signal and noise time-frequency coupling in dynamic noise environment in traditional method.Dynamic coupling path perception module quantifies the interactive characteristics of noise and signal in real time, combined with the double-channel architecture of complex domain phase-sensitive filtering and vibration trajectory matching filtering, realizes the accurate suppression of high-frequency transient interference and low-frequency periodic noise.

A kind of distributed multi-parameter sensing system based on multi-core optical fiber, including laser, laser light source is sent to the signal generator input trigger pulse drive respectively with the signal input end of phase-sensitive optical time domain reflectometer based on Rayleigh scattering and its demodulation device, Raman optical time domain reflectometer based on Raman scattering and its demodulation device, Brillouin optical time domain reflectometer based on Brillouin scattering and its demodulation device are connected, the signal output end of phase-sensitive optical time domain reflectometer and its demodulation device, Raman optical time domain reflectometer and its demodulation device, Brillouin optical time domain reflectometer and its demodulation device is connected with the signal input end of multi-core optical fiber through multi-core optical fiber fan-in fan-out module;The present application utilizes the principle of space division multiplexing, each fiber core in optical cable as separate sensing channel carries out measurement and signal transmission;Multi-core optical fiber fuses three kinds of distributed optical fiber sensing systems together, realizes in-situ measurement and mutual compensation decoupling of temperature, strain and vibration, improves the measurement precision of sensing system.

The application discloses a phase-sensitive optical receiving system for enhancing inter-satellite laser pointing measurement, comprising: an optical transceiver unit for receiving an input laser signal to be measured, collimating and beam-reducing the laser signal to be measured, obtaining a beam-reduced laser signal and outputting the same; a phase-sensitive amplification unit for receiving the input beam-reduced laser signal and pump laser, processing the beam-reduced laser signal and the pump laser, obtaining a power amplified signal and outputting the same; an optical receiver unit for receiving an optical amplified signal and a local oscillation laser, processing the optical amplified signal and the local oscillation laser, obtaining four electronic signals and outputting the same; and a data processing unit for receiving the four electronic signals, demodulating the four electronic signals, obtaining laser pointing information and outputting the same. The application implements noiseless amplification on an incident laser pointing signal through the phase-sensitive optical receiving system, and improves the detection sensitivity of a spacecraft laser pointing system.

The invention relates to a vehicle-type-based traffic flow monitoring DAS system and a signal processing method, and belongs to the technical field of intelligent traffic monitoring. A DAS system for monitoring traffic flow based on different vehicle types is characterized by comprising a sensing module based on a phase-sensitive optical time domain reflection technology and a self-adaptive signal processing module, according to the system, firstly, road vibration data are collected by using an optical fiber distributed acoustic sensing technology, vehicle vibration characteristics are selectively enhanced and background interference is suppressed in a key frequency band of 10-80 Hz through DAS-PCSE based on enhanced ultra-wavelet transform, and high-stability input characterization is generated; then, the preprocessed data are input into a lightweight DAS Trajectory Net, the network takes an encoder-decoder as a skeleton and introduces an adaptive feature enhancement module, and accurate recognition of a vehicle track is achieved; and finally, through a DAS Veple Classifier Net, a double-current signal processing module and lightweight convolution are utilized to efficiently fuse spatio-temporal information, and vehicle type discrimination is completed. According to the invention, the influence of low signal-to-noise ratio and complex background disturbance can be effectively overcome, and wide-area and all-weather vehicle-type-based traffic flow and vehicle speed monitoring can be realized with low calculation cost.

The invention relates to a magnetic resonance image reconstruction method and device, computer equipment and a storage medium, and the method comprises the steps: applying a phase-sensitive inversion recovery pulse sequence to a to-be-imaged object, collecting a magnetic resonance signal of the to-be-imaged object, and obtaining a to-be-processed image according to the magnetic resonance signal; removing a background first-order phase in the to-be-processed image to obtain a first dephasing image; according to the first dephasing image and a preset recognition model, removing a target background zero-order phase in the first dephasing image to obtain a second dephasing image; and extracting a real part component of the second dephasing image to obtain a target magnetic resonance image. By using the magnetic resonance image reconstruction method provided by the invention, the quality of the obtained target magnetic resonance image can be improved.

The invention relates to the technical field of optical fiber event detection, and discloses a phi-OTDR event detection method, system and device and a medium, and the method comprises the steps: obtaining the optical fiber signal data of an original phase-sensitive optical time domain reflectometer, and carrying out the first processing; constructing a deep learning model based on the residual network, training the deep learning model by using the training set, evaluating the performance through the verification set, and adjusting hyper-parameters according to an evaluation result to optimize the model; and inputting the data after the first processing into a trained deep learning model based on a residual network to extract high-level features of the optical fiber signals, and performing event identification and classification according to the high-level features. According to the method, the problems that the current OTDR event detection signal is interfered in noise, the model is insufficient in tiny event extraction capability, and the deep learning model is slow in convergence speed and poor in generalization capability are solved, automatic and accurate identification of the optical fiber event is realized, and the efficiency and reliability of optical fiber fault diagnosis are greatly improved.

A distributed acoustic sensing (DAS) system may include an optical fiber, a phase-sensitive OTDR (ϕ-OTDR) coupled to the optical fiber, and a processor cooperating with the ϕ-OTDR. The processor may be configured to train a plurality of machine learning networks with DAS data from the ϕ-OTDR based upon different respective optimizers, select a trained machine learning network from among the plurality thereof based upon a game theoretic model, and generate an acoustic event report from the DAS data using the selected trained machine learning network.

The invention relates to an urban underground pipeline external force damage and road collapse supervision method and device, and belongs to the technical field of pipeline external force damage and road collapse supervision, and the method comprises the steps: an improved high-sensitivity phase-sensitive optical time domain reflectometer monitoring system senses a vibration signal, and processes and converts the vibration signal into a time-frequency spectrogram; inputting the time-frequency spectrogram into a pre-trained abnormal vibration signal classification identification and risk determination model to obtain a diagnosis result, and outputting the diagnosis result in a structured format; the diagnosis result, the occurrence time and the geographic position are uploaded to an intelligent management and control platform in real time, the intelligent management and control platform dynamically labels a GIS map according to the event type and the risk level, and a structured electronic maintenance work order is generated; and the intelligent management and control platform monitors the maintenance progress in real time and ensures a work order closed loop. The system can effectively sense, diagnose and warn underground pipeline external force damage and road collapse in a low-cost, high-safety and easy-to-operate manner.

This invention relates to a phase-sensitive optical time-domain reflectometer based on orthogonal frequency division multiplexing (OFDM) pulse coding. A continuous laser beam is split into a local path and a probe path via an optical coupler. The probe path, driven by a radio frequency signal, generates multiple frequency-orthogonal intensity-coded pulse sequences through an optical intensity modulator. These sequences are arranged sequentially in time, possessing the same symbol information but different chip sequences. The Rayleigh backscattered light generated by the pulse sequences entering the sensing fiber under test undergoes coherent interference with the local light in an optical bridge and polarization diversity module. The signal acquisition circuit utilizes an unmatched filter to achieve pulse compression and Rayleigh scattering signal separation, and synthesizes the results of the pulse coding sequences at each frequency to obtain the strain signal. Compared with existing technologies, this invention achieves pulse compression by designing an unmatched filter, improving the signal-to-noise ratio while maintaining spatial resolution. Furthermore, by synthesizing the results of orthogonal frequency pulse sequences, coherent fading is eliminated, achieving fading-free, high signal-to-noise ratio strain measurement.

The atom magnetometer based on homodyne and differential detection is provided for the first time, detection light is divided into signal light and reference light through a 1 * 2 polarization-maintaining optical fiber coupler, and the signal light enters a gas chamber and interacts with polarized alkali metal atoms to induce magnetic field information; the reference light is subjected to high-frequency phase modulation and then subjected to homodyne coherent frequency mixing with the signal light to generate orthogonal phase signals, magnetic field information is extracted from the two paths of orthogonal signals through a homodyne and differential fusion detection mechanism, response signals are improved, low-frequency noise is suppressed, and the measurement precision, signal response and low-frequency sensitivity of the atom magnetometer are improved. Compared with a traditional single differential detection method, the phase sensitivity characteristic of homodyne detection and the common-mode noise suppression capability of differential detection are innovatively combined, and enhancement and high-fidelity extraction of detection signals and suppression of low-frequency noise are achieved through coherent demodulation and differential processing of double-path polarization modulation signals.

The invention discloses a fault monitoring electric control stop valve, belongs to the technical field of electric control stop valves, and solves the problems that the failure root of the electric control stop valve is caused by that cavitation bubbles are generated when fluid flows through a slit at a high speed and shock waves generated by bubble collapse erode a valve seat and a valve core under the extremely high pressure difference at the moment of opening and closing, and the microscopic progressive internal damage cannot be perceived by conventional electrical inspection; and corrosion pits and scouring traces on the sealing surface can be found only by disassembling. Comprising a valve body, an electric actuator fixedly connected to the valve body through a connecting frame, and a valve element arranged in the valve body. When the device works, modulation electromagnetic field induction eddy current is applied to the surface of the valve body, the microcosmic thermal characteristics of cavitation corrosion in a material are accurately extracted by utilizing the thermal response characteristic difference of a damaged area and combining a synchronous infrared thermal imaging and phase sensitive detection technology, and early damage identification and early warning without disassembly are realized; the problem that recessive material degradation cannot be detected through traditional inspection is solved.

This invention discloses an adaptive filtering method for phase-sensitive optical time-domain reflectometry (OTDR) signals. The method evaluates the quality of non-local mean filtering results by calculating correlation coefficients, and the filtering quality can be used to optimize the filtering parameters of the image filtering method. These parameters are first verified using a hypothetical standard signal and then applied to denoising a real signal from a phase-sensitive OTD instrument. Comparison of the correlation-optimized filtering parameters with those optimized using traditional peak signal-to-noise ratio (PSNR) and structural similarity methods shows that, except for slight differences in the neighborhood window size, the optimized filtering parameters are almost identical. This method is also applicable to image filtering of other two-dimensional periodic signals.

A distributed acoustic sensing (DAS) system may include an optical fiber, a phase-sensitive OTDR (φ-OTDR) coupled to the optical fiber, and a processor cooperating with the φ-OTDR. The processor may be configured to generate a series of covariance matrices for DAS data from the φ-OTDR, and determine an acoustic event based upon comparing the series of covariance matrices with a corresponding Toeplitz matrix.

The present application belongs to the field of optical fiber sensing technology, and particularly relates to a phase-sensitive distributed optical fiber temperature measuring device and method based on a tunable laser, which comprises a tunable laser, a pulse modulation module, a sensing module and a temperature measuring module, and is characterized in that: the tunable laser is used to calibrate different absolute temperatures corresponding to different center wavelengths by using the variable wavelength characteristics of the tunable laser, and the actual temperature to be measured is demodulated through a correlation demodulation module and a temperature calibration module; the injection locking technology is adopted to eliminate the wavelength drift problem of the tunable laser, suppress the harmonics generated in the frequency sweeping light modulation process of the tunable laser, and improve the measurement accuracy of the system. The present application solves the problem that the phase-sensitive optical fiber measurement method cannot measure the absolute temperature, and can be widely used in the field of high-precision distributed optical fiber temperature measurement.

The application provides an optical phase measurement method based on phase-sensitive non-Hermitian four-wave mixing, comprising generating a phase-sensitive non-Hermitian four-wave mixing process; detecting signal light and idler light emitted in the four-wave mixing process to obtain measurement results of a type-1 entanglement criterion and a type-2 entanglement criterion, and using the measurement results of the type-1 entanglement criterion and the type-2 entanglement criterion to realize measurement of an optical phase. The application uses a principle mechanism of the phase-sensitive non-Hermitian four-wave mixing process, and through non-Hermitian characteristics and optical phase sensitivity of the phase-sensitive non-Hermitian four-wave mixing process, measurement of a type-1 entanglement criterion is used to realize high-sensitivity optical phase measurement, and the application has the advantages of high robustness and higher sensitivity. The optical phase measurement method based on the phase-sensitive non-Hermitian four-wave mixing process has the advantage of high feasibility in realizing high-sensitivity optical phase measurement in combination with existing homodyne detection technology.

The invention provides a front low-noise light amplification method and system for a coherent detection laser radar, and the system comprises a continuous laser receiving and transmitting module which is used for transmitting detection light and receiving an echo signal, and the echo signal serves as first signal light; the double-pump generation module is used for generating second signal light and idler frequency light having a relative phase relation with the second signal light, and the second signal light and the idler frequency light serve as first pump light and second pump light respectively; the phase sensitive light amplification module is used for performing phase sensitive light parametric amplification after the first signal light is combined with the first pump light and the second pump light; the phase locking module is used for locking the relative phase between the double-pump light and the first signal light in the phase sensitive light amplification module; and the coherent detection module is used for detecting the first signal light amplified by the phase-sensitive optical parameter and demodulating information in the target. Weak optical signals can be amplified in a high-gain mode, amplification of same-frequency background noise can be restrained, and the signal-to-noise ratio and coherent detection efficiency of echo signals can be improved.

This invention relates to the field of fiber optic sensing, specifically providing a method and system for suppressing frequency drift in phase-sensitive optical time-domain reflectometry (OTDR) devices. The suppression method involves dividing an optical cable into several sampling intervals according to a preset length; acquiring the spatial phase difference of each sampling interval; acquiring the spatiotemporal phase difference of each sampling interval; acquiring a target optical cable segment and its frequency drift phase difference; acquiring the minimum spatial phase difference corresponding to the frequency drift pulse time based on the spatial and spatiotemporal phase differences; and correcting the frequency drift phase difference of the target optical cable segment based on the minimum spatiotemporal phase difference. Compared to existing technologies, this invention extracts the minimum spatiotemporal phase difference from the spatiotemporal phase information. The minimum spatiotemporal phase difference represents the frequency drift of the optical cable at the corresponding pulse time caused solely by the laser's influence. Therefore, the frequency drift phase difference can be corrected based on the minimum spatiotemporal phase difference, ensuring the normal operation of the optical cable.

The invention discloses a laser phase noise elimination method and system for a phi-OTDR (Optical Time Domain Reflectometer), solves the problem of dependence of a phase-sensitive optical time domain reflectometer on a high-cost narrow-linewidth laser in the prior art, and realizes reduction of the influence of the phase noise of the laser in combination with a signal processing algorithm. Therefore, the requirement of the system on the line width of the laser is relaxed, the system cost is greatly reduced, and the compatibility of a sensing system and a communication system is improved; the method comprises the following steps: injecting a composite detection pulse into a to-be-detected optical fiber to obtain backscattered light; performing coherent beat frequency on the backscattered light and the local oscillation light to obtain a synthesized complex amplitude electric signal; processing and synthesizing the complex amplitude electric signal, and separating a scattering signal component corresponding to each sub-pulse through a frequency domain filtering or decoding mode; calculating an instantaneous phase difference between the at least one pair of scattered signal components to obtain a spatial differential phase; wherein the space differential phase eliminates common phase noise introduced by the local oscillation light.

The invention provides a phase-sensitive optical time domain reflectometer, a measurement method and a readable storage medium, and a signal generation circuit of the phase-sensitive optical time domain reflectometer is configured to generate a radio frequency signal to drive a light intensity modulator to modulate detection light. Therefore, synchronous detection can be carried out on the sensing optical fiber to be detected by utilizing two groups of frequency division multiplexing sequences with difference, the phase variation in adjacent sampling intervals can be accurately solved by combining a differential de-folding algorithm, then demodulation results corresponding to different frequency parts are respectively de-folded to obtain de-folded phase results, and the detection accuracy of the sensing optical fiber to be detected is improved. Therefore, the problem of large-strain phase folding is solved, the large-strain range is recovered, further time sequence interleaving processing is carried out on the unfolded phase results, the unfolded phase results are rearranged and combined according to the time sequence, and therefore a high-sampling-rate and undistorted reconstruction result is reconstructed. According to the invention, accurate measurement of high-frequency response and large-strain-range dynamic strain can be realized.