113 results about "Time-domain reflectometer" 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 circuit board high-frequency characteristic detection analysis method and system based on a stub test platform, and the method comprises the steps: obtaining an S parameter of a PCB signal network based on a vector network analyzer (VNA), judging whether the signal transmission loss caused by a stub meets a detection requirement or not, and outputting the length of the stub and carrying out the TDR detection when a VNA detection result is unqualified; the size of a reflected signal of the PCB signal network is obtained based on a time domain reflectometer TDR, whether impedance change caused by a stub in a TDR curve is qualified or not is judged, and when a TDR detection result is not qualified, the specific position of the stub is output, and backdrill capacitance characteristic detection is carried out; capacitance characteristic parameters of the abnormal back drilling via hole are obtained based on back drilling capacitance characteristic detection, and the specific form of the stub is determined. The method and the system are specially used for detecting the stubs in the PCB high-density multilayer board, not only have the remarkable advantages of high precision, high speed and high reliability, but also provide solid technical support for accurate evaluation and strict quality control of product performance.

The invention relates to the technical field of elevator equipment detection, and discloses an elevator traveling cable dynamic fault detection method, system and device and a medium, and the method comprises the following steps: obtaining multi-mode state data of each line of a traveling cable and elevator operation state data; inputting the operation state data into a preset electromechanical coupling model to obtain a corresponding multi-dimensional health reference signal vector; performing time alignment on the multi-modal state data and the reference vector, and performing subtraction to obtain a multi-dimensional signal residual sequence; inputting the residual error sequence into a pre-training deep learning classification model to obtain a preliminary fault judgment result; a final result is confirmed through causal analysis; and if the fault exists, target fault information is obtained through the time domain reflectometer, and visual information is generated and sent to the human-computer interaction interface. According to the embodiment of the invention, the electrical characteristics of the cable and the mechanical motion state of the elevator are dynamically coupled, and high-precision and high-efficiency fault early warning and diagnosis are realized.

The invention provides an optical fiber detection method and system for an optical time domain reflectometer, and relates to the technical field of power grids. According to the invention, the multi-wavelength backscattering signal of the optical fiber link to be detected is acquired, preprocessed and converted into the sample to be detected containing the multi-wavelength one-dimensional waveform data and the multi-wavelength two-dimensional diagram data at the same time, so that the sequence characteristic of the light intensity of each wavelength changing along with time is reserved; and spatial features of correlation and structural information between wavelengths can be reflected through data conversion construction, and multi-dimensional and structured representation of optical fiber events is realized. And combined analysis and recognition are carried out by combining a fault recognition model, and a time sequence rule in a one-dimensional waveform and a spatial distribution mode in a two-dimensional diagram are cooperatively mined, so that deep fusion and intelligent analysis of optical fiber fault spatial-temporal characteristics are realized, and the recognition capability of a complex fault mode is improved. The technical problem of low accuracy of optical fiber fault detection with a single wavelength at present is solved, and the accuracy and reliability of optical cable line fault detection are improved.

An Optical Time-Domain Reflectometer (OTDR) trace correction method, an electronic device, and a storage medium are disclosed. The method may include: establishing a parameter decoupling equation according to a fiber loss coefficient and a Stimulated Raman Scattering (SRS) transfer coefficient in response to ignoring an SRS transfer amount amplified or absorbed by an OTDR wavelength in an Optical Transport Network (OTN) service; disabling a service wavelength of an OTN of an optical fiber transmission system, and acquiring, according to the parameter decoupling equation, a first OTDR trace of an OTDR simulation wavelength in the optical fiber transmission system when the service wavelength of the OTN is in a disabled state; determining a fiber loss coefficient according to the first OTDR trace.

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 provides a double-end optical lightning stroke positioning method and system applied to power overhead optical cables, and relates to the technical field of optical fiber sensing; the basic principle of positioning is to realize single-end lightning stroke positioning based on the obvious change of the polarization state of optical signals after the optical signals encounter lightning strokes; the application first uses counter-transmitted pulse polarized light to detect a single-end lightning stroke positioning point, then establishes a double-end positioning equation set to solve an actual lightning stroke positioning point, so that accurate lightning stroke positioning is realized; the application uses the Faraday optical rotation effect of lightning strokes on optical signals to realize lightning stroke positioning based on a polarized light time domain reflectometer; compared with traditional lightning stroke positioning, the application has low operation and maintenance cost, high precision, does not need wide-area accurate time synchronization, has a simple system, is convenient to install, and reduces the blind area of lightning stroke positioning.

A system and method for distributed temperature and strain sensing using Chirp-Pulse Coherent Optical Time-Domain Reflectometry (CP-COTDR) utilizes optical flow processing. The method involves constructing a two-dimensional (2-D) waterfall data array from collected CP-COTDR frames. Optical flow processing is applied directly to the 2-D data to estimate the local shift of features caused by external perturbations. The optical flow is preferably calculated using a weighted least squares method with an adaptive analysis window based on the local flatness of signal derivatives. This approach provides versatile and high spatial resolution, reduces accumulative errors, and enables efficient data processing compared to conventional cross-correlation techniques.

The invention discloses an in-operation OPGW icing tension monitoring method based on a micrometeorological temperature demodulation BOTDR. The method comprises the following steps: measuring through a Brillouin optical time domain reflectometer to obtain OPGW Brillouin frequency shift data; calibrating a Brillouin frequency shift temperature sensitivity coefficient and a Brillouin frequency shift tension sensitivity coefficient of the OPGW by using the data of the microclimate icing monitoring terminal; according to the Brillouin scattering principle, all Brillouin frequency shifts are converted into Brillouin equivalent temperatures; the external environment temperature of the OPGW is measured through the micro-meteorological icing monitoring terminal and is defined as temperature data of the micro-meteorological icing monitoring terminal; calculating a difference value between the Brillouin equivalent temperature and the temperature data of the microclimate icing monitoring terminal; and when the temperature difference value is greater than or equal to the temperature measurement precision of the Brillouin optical time domain reflectometer, the icing tension is calculated. According to the invention, the Brillouin frequency shift temperature sensitivity coefficient and the Brillouin frequency shift tension sensitivity coefficient can be directly calibrated on line, and the calibration result and the icing tension monitoring result are more accurate.

In some examples, high speed bidirectional OTDR-based testing may include transmitting data from a first end of a device under test (DUT) towards an optical time-domain reflectometer (OTDR) that is operatively connected to a second opposite end of the DUT. Further data that is transmitted by the OTDR may be received from the second opposite end of the DUT towards the first end of the DUT. Based on an amplitude of the further data, a direction of receiving of the further data may be adjusted towards a first receiver or towards a second receiver.

The invention relates to a signal noise suppression system based on an optical time domain reflectometer, and the system comprises a transmitting unit which is used for generating an optical time domain reflection pulse signal with preset parameters according to control information; the testing unit is connected with the transmitting unit and the optical fiber to be tested and is used for injecting the received pulse signal into the optical fiber to be tested and guiding the reflected echo optical signal into the receiving unit; the receiving unit is connected with the testing unit and is used for receiving the echo optical signal and converting the echo optical signal into a digital signal, so that the data processing unit can receive and process the digital signal conveniently; and the data processing unit is respectively connected with the receiving unit and the transmitting unit and is used for carrying out range dynamic filtering processing according to the data signal transmitted by the receiving unit, storing the filtered signal and transmitting control information to the transmitting unit, so that the transmitting unit generates a pulse signal with a preset parameter according to the signal. The technical problems of signal broadening deformation and time delay, slow system operation, increased test blind area and the like in the prior art are solved.

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 an IC carrier board testing method and system, mainly relates to the technical field of IC carrier board, to solve the problem of single detection dimension, insufficient positioning accuracy and low test efficiency of the existing scheme. Including: screening out test points with contact resistance value exceeding threshold value or not conducting as detection objects; using TDR time domain reflectometer to perform impedance test under 1GHz frequency band, identifying impedance abnormal area; monitoring the temperature distribution of the IC carrier board, obtaining monitoring temperature points exceeding the preset temperature; determining the monitoring temperature points coinciding with the detection objects or the impedance abnormal area as the abnormal heat conduction points between the multilayer circuits, recording the temperature gradient data of the abnormal heat conduction points; using a preset torque to perform a preset micro stress loading on the IC carrier board; comparing the resistance value change rate of the IC carrier board before and after stress application, and determining the defect type of the carrier board according to the specific preset defect interval where the resistance value change rate falls.

1. Name of the product in this design: Optical Time Domain Reflectometer (Simplified Version). 2. Purpose of this design: For testing fiber optic signals. 3. The key design feature of this product is its shape. 4. The image or photograph that best illustrates the design's key points: a 3D model.

The invention belongs to the field of distributed optical fiber sensing and coding and decoding, and provides a Brillouin optical time domain reflection signal decoding method and system based on rising edge assistance. The rising edge assistance-based Brillouin optical time domain reflection signal decoding method comprises the following steps: acquiring a time domain coding response signal corresponding to a coding pulse sequence injected into an optical fiber by a Brillouin optical time domain reflectometer; performing discrete Fourier transform on the time domain coding response signal to obtain a frequency domain coding response signal; according to the signal increment and the duration of the rising edge of the time domain coding response signal, reconstructing a decoding function and replacing the decoding function in the frequency domain coding response signal with the reconstructed decoding function; the decoding function is a sequence formed by a decoding weight corresponding to each code element; and performing inverse discrete Fourier transform on the frequency domain coding response signal to obtain a decoded signal. According to the method, the signal-to-noise ratio of the decoded SpBS signal can be remarkably improved, and the Brillouin frequency shift (BFS) extraction precision is enhanced.

The invention relates to the field of optical fiber pipeline monitoring, in particular to a safety monitoring method and equipment for an optical fiber pipeline and a medium, and the method comprises the steps that an unmanned aerial vehicle carries an optical time domain reflectometer and environment monitoring equipment to fly along the pipeline, and reflected light information and environment parameters such as temperature, humidity, air pressure and flight relative height are synchronously obtained. And after an initial leakage position is determined based on the reflected light information, an adaptive leakage position correction model is selected from a preset reference table according to the environmental parameters corresponding to the position. And the offset is calculated by substituting the environmental parameters into the correction model, and the target leakage position is obtained. According to the method, multi-source data fusion and a precise correction model are utilized, interference of environmental factors on positioning is effectively eliminated, the precision and reliability of optical fiber pipeline leakage positioning are remarkably improved, and the method is suitable for a pipeline safety monitoring scene in a complex environment.

An object of the present invention is to provide an optical transmission line test apparatus and a test method capable of measuring a cumulative crosstalk of an optical transmission line in which a plurality of uncoupled multi-core fibers are connected in series from one end side with an OTDR.An optical transmission line test apparatus 301 according to the present invention measures a cumulative crosstalk of an optical transmission line 50 in which a plurality of uncoupled multi-core fibers 50-i are connected in series. The optical transmission line test apparatus 301 includes a test light input unit 10 that inputs optical pulses to each of cores of the uncoupled multi-core fiber 50-1 at one end 50a of the optical transmission line 50; a reception unit 20 that receives backscattered light for each of the cores output from one end 50a; and a calculation unit 30 that acquires a loss distribution occurring in each of the cores from the backscattered light, and calculates the cumulative crosstalk from a connection loss at a connection point zj of the uncoupled multi-core fiber obtained from the loss distribution and a known inter-core mode coupling of each of the uncoupled multi-core fibers 50-i.

The invention relates to an optical fiber link fault diagnosis method and device, computer equipment, a readable storage medium and a program product. The method comprises the following steps: acquiring a time domain power fluctuation characteristic of the optical fiber link through an intelligent optical module, and acquiring a space domain performance fluctuation characteristic of the optical fiber link through an optical time domain reflectometer; fusing the time domain power fluctuation feature and the space domain performance fluctuation feature to obtain a fused fluctuation feature; and determining a fault diagnosis result of the optical fiber link according to the fusion fluctuation characteristics. By adopting the method, the fault diagnosis efficiency of the optical fiber link can be improved.

The application provides a blind person discrimination device, system and method based on a distributed optical fiber sensing device.The device comprises an optical time domain reflectometer module, a signal preprocessing module, a signal cutting module, a signal feature extraction module and a signal classification module.The method provides a high recognition rate without video monitoring equipment and wearable sensing equipment, more comprehensively and effectively provides application support for the field of security and blind person travel, enhances the adaptability for different human body recognition, and identifies the source of the human body walking signal accepted by the current device, whether it is a visually impaired user or a normal user, so as to provide related services for the visually impaired user in the future.The long-time and short-time feature joint recognition mode is adopted in the feature extraction algorithm, and the accuracy is further improved.

An optical fiber measurement system includes an optical time-domain reflectometer, a wavelength division multiplexer, and a signal generator. The signal generator sends a signal light ray to the wavelength division multiplexer. The optical time-domain reflectometer sends two measurement light rays whose wavelengths are respectively longer than and shorter than a wavelength of the signal light ray to the wavelength division multiplexer. The wavelength division multiplexer combines the two measurement light rays and the signal light ray, sends a combined light ray to an optical fiber, and sends a light ray returned by the optical fiber to the optical time-domain reflectometer, so that the optical time-domain reflectometer determines performance of the optical fiber based on the returned light ray.

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.

Aspects of the subject disclosure may include, for example, determining distinct timing offsets between an input port and output ports of a multiport optical device. An optical signal is injected at an input port of the device to obtain output signals at the output ports, which are injected into downstream fibers. An optical multipath return signal is received via the input port of the device, including a combination of measured events including reflections, backscatter, or both. A number of similar events expected in the number of downstream optical fibers is calculated to obtain an expected multipath signature based on configuration data. Results of the optical multipath return signal are then compared to the expected multipath signature to obtain comparison results. One of the measured events is distinguished from the others based on the first comparison results and the distinct timing offsets. Other embodiments are disclosed.

The embodiment of the invention provides a substrate wiring open-circuit defect positioning method and device and a medium, and the method comprises the steps: respectively testing the same test ends of a target signal line of a bad product and a target signal line of a corresponding good product through a time domain reflectometer when it is determined that the target signal line of the bad product has an open-circuit defect; obtaining a first reflection time corresponding to the cut-off of the target signal line routing of the defective product and a second reflection time corresponding to the cut-off of the target signal line routing of the good product; and according to the first reflection time, the second reflection time and the total wiring length of the target signal line, determining the position of the open circuit defect in the defective product. According to the method, rapid positioning and focusing of substrate wiring open circuit defects are achieved, defect loss in the analysis process is avoided, the analysis process is greatly shortened, a large amount of analysis time is saved, and a timely improvement basis is provided for the technological process.

The invention discloses a track zero calibration method of an optical time domain reflectometer and a related product, and the method comprises the steps that the optical time domain reflectometer emits a short pulse signal which sequentially passes through a reference optical fiber and an optical fiber to be measured, an original track curve corresponding to the short pulse signal is obtained, the reference optical fiber is arranged in the optical time domain reflectometer, and the reference optical fiber is arranged in the optical time domain reflectometer; the length of the reference optical fiber is greater than the spatial resolution of short pulse signal scanning; based on the original trajectory curve, determining reflected light power corresponding to the reference optical fiber; obtaining a first translation amount of the original trajectory curve based on the reflected light power corresponding to the reference optical fiber; and translating the original trajectory curve based on the first translation amount, completing calibration of a zero point, and obtaining an absolute loss trajectory curve corresponding to the to-be-measured optical fiber. Therefore, after zero calibration, the longitudinal axis value of the absolute loss trajectory curve can directly correspond to the absolute loss of each position of the optical fiber to be measured, and the trajectory curves of the same optical fiber at different moments can be conveniently compared, so that the readability of the trajectory curve is improved.

A method and system of measuring the PMD of an optical fiber under test (FUT). A polarization-sensitive optical time domain reflectometer (POTDR) is used to inject into the FUT and from a proximal end thereof, a test signal comprising a series of repeated light pulses and detecting a corresponding polarization-analyzed return light signal coming back from the optical fiber and representing back-reflected light from a light reflector connected to a distal end of the FUT. The plurality of polarization-sensitive acquisitions defines at least one pair of acquisitions performed with mutually different but closely-spaced wavelengths and substantially the same state of polarization (SOP). The process may be repeated for a plurality of pairs of acquisitions performed with at least one of a plurality of mutually-different center wavelengths and a plurality of mutually-different SOPs, and a value of the PMD for the FUT is calculated therefrom.

The application discloses a kind of distributed optical fiber monitoring sensing optical cable damage location method, it is related to distributed optical fiber monitoring technical field.The method includes: using OTDR optical time domain reflectometer to carry out preliminary measurement to sensing optical cable, it is judged whether optical cable exists damage and the preliminary measurement distance of damage point when existing damage;According to distance threshold value, it is judged whether bare optical fiber is fused, and OTDR secondary measurement is carried out, according to the measurement result record optical fading and the secondary measurement distance of each damage point;According to the optical fading, damage point is divided into two categories of " serious attenuation or broken fiber damage " and " moderate and below attenuation damage ", and the position of final damage point is positioned specifically.The application can be monitored by combined use of existing equipment of distributed optical fiber monitoring project itself, without separately purchasing other equipment.And, the optical cable damage location precision of the application can reach one meter, the positioning cost is low, the effect is good, and it is also applicable to the damage location of other communication optical cable.

A kind of weak reflection grating array reflectivity measurement method, using optical time domain reflectometer OTDR, including direct current light source, modulator, erbium-doped fiber amplifier, circulator, photoelectric detector, data acquisition card, data analysis processing module and display module;1) weak reflection grating array is accessed to above-mentioned measurement system, the weak reflection grating array to be measured is accessed to the second port of circulator;2) the output port of laser is connected with the input port of modulator;Laser output direct current light signal is modulated into probe light pulse by modulator, is amplified after being amplified by erbium-doped fiber amplifier, forms probe signal by entering the weak reflection grating array to be measured through circulator;3) the input port of photoelectric detector is connected with the third port of circulator;The input port of data acquisition card is connected with the output port of photoelectric detector;It is sent to data acquisition card by photoelectric detector output port;4) the output port of data acquisition card is connected with data analysis processing module.

The embodiment of the invention provides an optical fiber fault positioning method, system and device, a readable storage medium and a product. The method comprises the following steps: acquiring optical time domain reflectometer OTDR data of a target optical fiber link; identifying a fault reflection peak in the OTDR data, and calculating the linear distance between the optical line terminal and the breakpoint according to the propagation speed of the light in the optical fiber and the time difference between the light in the OTDR data and the fault reflection peak; matching the linear distance with a distance interval of each optical cable sub-segment in a pre-constructed bidirectional topological graph of the optical fiber network, and determining a target optical cable sub-segment where the breakpoint is located; acquiring a starting point coordinate, an end point coordinate and a length of the target optical cable sub-segment; and based on a coordinate interpolation algorithm, according to the starting point coordinate, the end point coordinate, the length and the linear distance of the target optical cable sub-segment, calculating the physical position of the breakpoint. According to the embodiment of the invention, automatic positioning of the optical fiber fault can be realized, the timeliness of fault discovery is improved, and manual intervention and field operation time are reduced.

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 disclosure relates to the optical fiber sensing technology, and more particularly to an optical time-domain reflectometer and an interference fading rejection method, and includes a laser device, a frequency division multiplex modulator, a circulator and a signal processing device, wherein the frequency division multiplex modulator includes a first modulator, a second modulator, a first attenuator and a second attenuator, the laser device is used to acquire a coherent light source, the coherent light source passes sequentially through the first modulator and the first attenuator to acquire the first pulsed optical signal, the coherent light source passes sequentially through the first modulator and the second modulator to acquire the second pulsed optical signal, the coherent light source passes sequentially through the second attenuator and the second modulator to acquire the third pulsed optical signal, and the output of multiple pulsed optical signals can be realized by different combinations of the first modulator, the second modulator, the first attenuator and the second attenuator, saving hardware costs compared to existing technologies.