89 results about "Reflectometry" patented technology

The invention discloses an optical fiber three-dimensional shape sensor based on an optical frequency domain reflection technology and an application method of the optical fiber three-dimensional shape sensor, the optical fiber three-dimensional shape sensor comprises a base material and more than three optical fibers, and all the optical fibers are spirally wound and fixed on the surface of the base material at equal intervals and constant screw pitches to form distributed sensing units; according to the application method, measurement signals of all the optical fibers are obtained, and axial strain and strain are calculated; calculating the total curvature vector of the reconstruction curve of the measured object; calculating a bending direction angle and a curvature of the reconstruction curve of the measured object; performing differential calculation on the bending direction angle to obtain the torsion rate of the reconstructed curve of the measured object; and reconstructing the three-dimensional shape of the measured object according to the curvature and the torsion of the reconstructed curve of the measured object. The invention aims to realize synchronous measurement of bending, torsion and axial strain by using a distributed sensing unit formed by a multi-fiber structure which is spirally wound at the same interval and at a constant screw pitch.

The invention belongs to the technical field of distributed optical fiber sensing, and relates to a phase-frequency noise suppression optical frequency domain reflection measurement method and system without an auxiliary interferometer. The measurement method comprises the following steps: acquiring positive and negative double-sideband sweep-frequency light with the same sweep-frequency range and opposite sweep-frequency directions; dividing the positive and negative double-sideband sweep frequency light into double-sideband detection light and double-sideband local oscillation light according to a preset proportion; configuring a pseudo-random noise code, and modulating the pseudo-random noise code to the double-sideband probe light to obtain spread spectrum double-sideband probe light; the spread spectrum double-sideband detection light enters the sensing optical fiber and is reflected back to the backward Rayleigh scattering light, and the backward Rayleigh scattering light and the spread spectrum double-sideband local oscillation light interfere with each other to output up-down sweep frequency beat frequency signals; separating the upper and lower sweep-frequency beat-frequency signals to obtain an upper sweep-frequency beat-frequency signal and a lower sweep-frequency beat-frequency signal; and after the upper sweep frequency beat frequency signal and the lower sweep frequency beat frequency signal are respectively decoded, a beat frequency signal is separated through band-pass filtering, the beat frequency signal is subjected to frequency mixing processing to obtain a frequency mixing signal after phase frequency noise suppression, and the frequency spectrum of the frequency mixing signal is analyzed.

Systems and methods for measuring wellhead displacement include receiving a speckle interferogram from an imaging sensor based on infrared light transmitted to and reflected from a portion of a wellhead; correlating the speckle interferogram with a reference speckle interferogram, the reference speckle interferogram indicating a previous position of the portion of the wellhead; and measuring a displacement of the wellhead based on the correlation of the speckle interferogram and the reference speckle interferogram.

The invention provides an optical frequency domain reflectometer grating array multiplexing demodulation method based on peak position estimation, and the method comprises the steps: in quasi-distributed sensing based on optical frequency domain reflectometer grating array multiplexing, in order to obtain an acceptable grating spectral measurement resolution ratio, carrying out peak position estimation; in the prior art, dense interpolation needs to be carried out on a spectrum of which the spectral resolution is lower than a threshold value required by demodulation, but the data volume is greatly increased, so that the calculation rate is slowed down, and the demodulation efficiency is low. According to the method, peak position estimation is carried out on the cross-correlation spectrum of the grating spectrum of which the spectral resolution is lower than the threshold required by demodulation, so that dense interpolation is avoided, and the problem of low demodulation efficiency caused by dense interpolation is improved; meanwhile, in order to overcome the problems of spectrum distortion caused by grating inscribing defects and spectrum splitting caused by gaps between gratings in the traditional demodulation process, the robustness of system demodulation is ensured to the maximum extent on the basis of improving the system demodulation efficiency.

Using “in-situ on-die time-domain reflectometry (TDR)” with data signal paths of integrated circuits, printed circuit boards, and data processing equipment and systems allows testing, verification and troubleshooting of data channel signal path impedance variations including the package, escape routing, socket, board, and cable / connectors provides fast characterization thereof. Operation of “in-situ on-die TDR” uses existing analog-to-digital converter (ADC) and data transmitter (TX) drivers of an integrated circuit to act as a TDR sampling head by performing a user interface-based TDR sampling with a step-waveform generated by an integrated circuit TX driver. Then sampling the step-waveform with the ADC of the integrated circuit using spline interpolation to obtain the over-sampled waveform. Once the sampled step-waveform is obtained, the TDR profile of the sampled data channels may be calculated. Large amounts of impedance variation data may thus be collected during either integrated circuit manufacturer or customer-built data communications channel testing.

The invention discloses a laser phase noise compensation device and method for an optical frequency domain reflectometer, and relates to the technical field of distributed optical fiber sensing, and the compensation device comprises a sweep frequency laser source module which is used for outputting a first beam of sweep frequency laser and a second beam of sweep frequency laser; the main interferometer module is used for receiving the first beam of sweep frequency laser and generating a first beat frequency signal related to the scattering point position of the sensing optical fiber; the auxiliary interferometer module is used for receiving the second beam of frequency sweeping laser and generating a second beat frequency signal related to the weak reflection point position of the auxiliary optical fiber; and the signal processing module is used for acquiring the first beat frequency signal and the second beat frequency signal and respectively extracting phase terms of the sensing optical fiber and the auxiliary optical fiber so as to realize phase noise compensation. According to the compensation method, the function of the compensation device is achieved, namely phase noise compensation is achieved, then the frequency spectrum of compensation information is analyzed, and strain information along the sensing optical fiber is demodulated. According to the invention, uniform compensation of phase noise is realized, and the system measurement distance, the spatial resolution and the strain precision are improved.

A metrology system includes an illumination source generating illumination beams. Illumination optics direct the beams to a sample surface at non-zero incidence angles. Detectors collect light from the sample surface, with collection optics directing this light to the detectors. A controller with processors executes program instructions to receive metrology data from detectors based on collected light. The metrology data includes measurements at multiple tilt angles based on non-zero incidence. The processors determine a bottom critical dimension value at zero-degree incidence by extrapolating measurement data collected at the multiple tilt angles.

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.

A metrology system includes an illumination source generating illumination beams. Illumination optics direct the beams to a sample surface at non-zero incidence angles. Detectors collect light from the sample surface, with collection optics directing this light to the detectors. A controller with processors executes program instructions to receive metrology data from detectors based on collected light. The metrology data includes measurements at multiple tilt angles based on non-zero incidence. The processors determine a bottom critical dimension value at zero-degree incidence by extrapolating measurement data collected at the multiple tilt angles.

The invention relates to a cable fault identification method based on a frequency domain reflection method, and belongs to the technical field of detecting faults in a cable by adopting a pulse reflection method in electrical variable measurement. The method comprises the following steps: setting interval time for increasing sine wave signal frequency to divide moments; calculating an initial frequency f0, and transmitting a sine wave signal with the frequency f0 and the phase of 0 degree into the cable; and then calculating the phase offset at each moment, taking four times of the sine wave signal frequency as the lower limit frequency of the frequency domain reflection method at the moment when the phase offset is equal to 180 degrees for the first time, and further carrying out cable fault identification. According to the method, the lower limit frequency of the frequency domain reflection method is accurately set according to the actual characteristics of the to-be-detected cable, so that omission of cable fault key characteristics is avoided, and the identification accuracy is greatly improved.

To provide an X-ray reflection analysis system and X-ray reflection analysis method utilizing multi-order mode signals.SOLUTION: An X-ray reflection analysis system includes an X-ray generator, an X-ray optical element group, an X-ray detector and a processing device. The X-ray generator generates a measurement X-ray beam (S10). The X-ray optical element group guides the measurement X-ray beam to a to-be-measured sample (S11). The X-ray detector receives the to-be-measured X-ray signal generated by the measurement X-ray beam irradiating the to-be-measured sample (S12). The processing device collects the to-be-measured X-ray signal and extracts mode signals (S13); performs a first fitting analysis process on the mode signals whose order is less than a predetermined order to generate initial parameter ranges (S14); and based on the initial parameter ranges, performs a second fitting analysis process on the mode signals whose order is greater than or equal to the predetermined order, to generate parameter fitting results (S15).SELECTED DRAWING: Figure 5

This invention relates to the field of optical time-domain reflectometry (OTDR) technology, and provides a method and apparatus for detecting multipath-multiplexed OTDR signals. Once an abnormal OTDR reflection signal is detected at the common reflection output of a DWDM device, the optical path to be detected corresponding to the current OTDR detection signal period is identified. Based on the pre-calculated ideal detection time for each optical path to be detected, one or more optical paths covered by the acquired OTDR reflection signal are selected. For the selected one or more optical paths to be detected, their respective preset initial periods are adjusted to their corresponding ideal detection times, thus performing a second round of OTDR detection based on the selected results, thereby accurately locating the optical path where the OTDR detection anomaly occurred. This invention automatically adapts by setting different numbers of wavelengths and the period of the emitted signal from a tunable wavelength laser.

This invention belongs to the field of distributed optical fiber sensing technology and relates to a method for synergistic suppression of phase noise and distortion in optical frequency domain reflection using coded differential methods. The method includes: acquiring upper and lower sweep beat frequency signals; separating the upper and lower sweep beat frequency signals to obtain an upper sweep beat frequency signal and a lower sweep beat frequency signal; acquiring the upper and lower sweep beat frequency electrical signals; delaying the upper sweep beat frequency electrical signal by a spatial resolution and then mixing it with the lower sweep beat frequency electrical signal, or delaying the lower sweep beat frequency electrical signal by a spatial resolution and then mixing it with the upper sweep beat frequency electrical signal, to obtain a mixed signal with phase noise and frequency domain distortion suppressed, and analyzing the Fourier frequency domain spectrum of the mixed signal. This invention also provides a system for synergistic suppression of phase noise and distortion in optical frequency domain reflection using coded differential methods, including a positive and negative double-sideband sweep frequency acquisition device, a beam splitter, a spread spectrum device, an interferometer, a beat frequency signal acquisition device, and an electrical delay unit. This invention can effectively suppress phase noise and frequency domain distortion noise.

The invention relates to a computer-implemented method (100) for a time-domain reflectometry analysis of an object, wherein the analysis comprises measuring the object using a measurement signal and a reflection signal based on the interaction of the measurement signal with the object, the method (100) comprising: providing (110) a first actual impedance profile characterizing the reflection signal over time; determining (120) a frequency-dependent line impedance of the object based on the first actual impedance profile; providing (130) the frequency-dependent line impedance.

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 application discloses a dynamic sweep frequency range compensation method of an optical frequency domain reflectometry system, comprising the following steps: reading an actual beat frequency sequence of a main interferometer and an auxiliary interferometer, wherein the actual beat frequency sequence is obtained by primary sampling of an actual beat frequency sequence of the main interferometer and the auxiliary interferometer under a preset sweep frequency range, and the preset sweep frequency range is greater than a theoretical sweep frequency range required by the optical frequency domain reflectometry system under a target application scenario; determining a mapping relationship between time and wave number according to the actual beat frequency sequence of the auxiliary interferometer; mapping a resampling wave number sequence with equal wave number intervals to a time domain according to the mapping relationship between time and wave number, to obtain a resampling time sequence, wherein the resampling wave number sequence is constructed according to the theoretical sweep frequency range; and resampling the actual beat frequency sequence of the main interferometer according to the resampling time sequence, to obtain a theoretical beat frequency sequence of the main interferometer under the theoretical sweep frequency range. The dynamic sweep frequency range compensation method can adapt to the dynamic change of the sweep frequency range for compensation. The application further discloses an optical frequency domain reflectometry system and a demodulation method based on the above dynamic sweep frequency range compensation method.

This invention discloses a device for locating vibration events on power transmission lines. The device includes a pulsed laser module, an optical pulse amplifier, an optical fiber circulator, an optical fiber polarizer, a sensing optical fiber, a photodetector, a data acquisition card, and a data processing and control unit. It utilizes the optical fiber inherent in the power transmission line or a separately laid optical fiber as the sensing fiber. While the optical pulse propagates in the sensing fiber, it generates a Rayleigh scattering signal. Vibration events on the power transmission line disturb the polarization state and phase of the Rayleigh scattering signal, resulting in a significant difference in noise convergence in the obtained optical time-domain reflectometry curve before and after the location of the induced vibration on the sensing fiber. Therefore, the location is determined by identifying the convergence start point. This device is suitable for locating external vibration sources on quasi-static power transmission lines and has advantages such as long monitoring coverage distance, high positioning accuracy, and low false alarm rate.

The invention relates to a facility (1) for cable assembly and a test method, the facility having a conductor support (30) which is provided for transporting and holding at least one conductor (40), a time-domain reflectometry measuring device (10) which is provided for performing a high-frequency measurement, and a contact device (20) which is movable relative to the conductor (40) and the time-domain reflectometry measuring device (10) and which is connected to the time-domain reflectometry measuring device (10) via a high-frequency connection (12), wherein the contact device (20) is designed to contact the conductor (40) in a high-frequency manner. The invention also relates to a test method for cable assembly at the facility (1).

This invention discloses an automated inspection system for semiconductor packaging wire bonding quality, relating to the field of semiconductor packaging technology. It includes: a multi-frequency signal transmitting module for sequentially transmitting high-frequency, mid-frequency, and low-frequency electrical signals to the wire bonding; a receiving module for receiving the multi-frequency electrical signals transmitted by the wire bonding and acquiring the signal strength of each frequency band in real time; a thermal noise detection module for detecting the thermal noise level in the wire bonding; a time-domain reflectometry module for transmitting high-frequency pulse signals to the wire bonding, detecting the reflection time and waveform characteristics of the signals in the wire bonding, and identifying physical defects in the wire bonding; and a data analysis module for comprehensively analyzing the multi-frequency signal strength, thermal noise level, and time-domain reflectometry waveform characteristics after temperature compensation to determine the wire bonding quality. In the comprehensive data analysis, all detection data are integrated and analyzed to achieve comprehensive inspection of wire bonding quality, significantly improving the accuracy and reliability of the inspection.

A plasma processing chamber has an upper window with a coil disposed above the upper window. A coil connection enclosure is disposed above the coil. A metrology enclosure is disposed above the coil connection enclosure. A spectral reflectometry system is disposed within the metrology enclosure. The spectral reflectometry system includes an optical collimator positioned to direct a beam of light through an opening in the metrology enclosure, an opening in the coil connection enclosure, and the upper window into the plasma processing chamber. The optical collimator is also configured to receive reflected light from within the plasma processing chamber, where the reflected light passes through the upper window and through the opening in the coil connection enclosure and through the opening in the metrology enclosure. A tip angle and a tilt angle of the optical collimator are remotely adjusted to optimize an orientation of the optical collimator.

In a surgical system, an endoscope can extend distally toward a target site. A sensing fiber extending to a distal end portion of the endoscope may include a fiber Bragg grating disposed at a distal end portion of the sensing fiber. The sensing controller may direct the sensing light distally along the sensing fiber such that at least some of the sensing light is reflected from the fiber Bragg grating as reflected light. The sensing controller may perform an optical frequency domain reflection measurement on the reflected light to determine a parameter value at the fiber Bragg grating, such as a pressure value or a temperature value. Processing circuitry may analyze the parameter value to determine that a parameter, such as pressure or temperature, at the target site satisfies a specified condition, such as too high, and in response, generate an alarm data signal or perform an appropriate task.

The application discloses a compensation device and method for laser phase noise of an optical frequency domain reflectometer, and relates to the technical field of distributed optical fiber sensing. The compensation device comprises a sweep laser source module, a main interferometer module, an auxiliary interferometer module and a signal processing module. The sweep laser source module is used for outputting a first sweep laser beam and a second sweep laser beam. The main interferometer module receives the first sweep laser beam and generates a first beat frequency signal related to the position of a scattering point of a sensing optical fiber. The auxiliary interferometer module receives the second sweep laser beam and generates a second beat frequency signal related to the position of a weak reflection point of an auxiliary optical fiber. The signal processing module collects the first beat frequency signal and the second beat frequency signal, extracts phase terms of the sensing optical fiber and the auxiliary optical fiber respectively, and realizes phase noise compensation. The compensation method realizes the function of the compensation device, that is, realizes phase noise compensation, analyzes the spectrum of compensation information again, and demodulates strain information along the sensing optical fiber. The application realizes uniform compensation of phase noise, and improves the system measurement distance, spatial resolution and strain accuracy.

In one implementation, a method of monitoring film thickness on a substrate, comprises: generating light from a light source; collimating the light from the light source to form a collimated beam; reflecting the collimated beam off of a surface to be measured to produce a reflected beam; splitting the reflected beam with a dichroic mirror, wherein the reflected beam splits into a first beam and a second beam; receiving, by a pyrometer, the first beam from the dichroic mirror; receiving, by a spectrometer, the second beam from the dichroic mirror; and analyzing data derived from the pyrometer and the spectrometer to determine one or more characteristics of the surface to be measured.

A temperature increase detection system (300) for an environment consisting of several distinct zones (Z1-Z10), the system comprising a branched cable network with several branches (CS1-CS10), each intended to be deployed in one of the zones, and at least one reflectometry device (DR1) connected to one end of at least one branch of the network and configured to: Acquire an initial reflectometry measurement corresponding to an initial state of said branched cable network; Acquire a current reflectometry measurement corresponding to a current state of said branched cable network; Compare the current reflectometry measurement to the initial reflectometry measurement to infer a temperature increase on one of the branches of said network. Figure 3

This application discloses a predictive maintenance system, method, sensor network, and storage unit for belt conveyors. It includes a multi-core optical cable and several silicon photonic triaxial accelerometers connected to different fiber branches therein. The application feeds detection light into the silicon photonic triaxial accelerometers via a silicon photonic demodulation and control unit. Based on the reflection of the detection light, it calculates the acceleration at each sensor's location to obtain the vibration state changes in the time domain along the belt conveyor in three orthogonal directions. Correspondingly, it extracts features, identifies faults, and generates predictive maintenance strategies. This application can proactively and in real-time assess the risk of abnormal belt conveyor faults and provide early warnings. Its sensing nodes are completely passive and intrinsically safe; it has a wide frequency response and high sensitivity; it uses a multi-point triaxial synchronous acquisition method to obtain equipment attitude information; it is suitable for long-distance, large-scale deployment with controllable costs; and it can also support predictive maintenance based on big data and artificial intelligence.

An electric wire inspection system and method that can sensitively detect damage on an electric wire, and an electric wire capable of being inspected using the same. The electric wire inspection system includes: an inspection unit which performs electric wire inspection wherein a characteristic impedance between two conductive members of the electric wire is obtained as a response signal by time domain or frequency domain reflectometry; a storage unit which stores the response signal obtained at a first time point; and an analysis unit which retrieves the response signal obtained at the first time point from the storage unit, compares it with the response signal obtained at a second time point later than the first time point, and, if a difference exists between the two response signals, correlates a region in which the difference exists in the response signals with a position along an axial direction of the electric wire.

This invention relates to the fields of optical fiber communication and sensing technology, and discloses a method and system for submarine optical fiber communication and vibration monitoring based on distributed sensors. The method includes: simultaneously conducting forward communication via submarine optical fiber as a distributed optical fiber sensing medium for reverse vibration monitoring based on optical time-domain reflectometry (OTDR); acquiring real-time sensing data through multiple distributed sensor nodes set along the optical fiber; acquiring real-time vibration signals during reverse vibration monitoring; matching the real-time sensing data with historical data; generating confidence scores for the real-time sensing data based on the matching results; constructing and solving a vibration monitoring model based on sparse dictionary matching of vibration events based on the real-time vibration signals; obtaining the event type corresponding to the real-time vibration signals based on the solution results; and using confidence scores to improve the event matching and search efficiency during vibration monitoring. This invention can perform vibration monitoring while ensuring communication, improving the accuracy, positioning precision, and efficiency of vibration monitoring.

This invention specifically relates to a method for assessing the severity of cable faults based on the frequency domain reflection method, belonging to the field of distribution network cable fault detection technology. This invention only optimizes and adjusts the software level based on the existing FDR method, without requiring redevelopment or modification of the hardware system, thus possessing the technical advantages of low cost and easy implementation. Taking into account both transmission line theory and the theoretical principles of FDR, it innovatively proposes a cable anomaly peak identification method based on multi-parameter constraints. This method automatically identifies and locates reflection peaks in the spectrum and performs a graded assessment of the severity of defects, effectively filling the gap in existing cable detection technologies for intelligent FDR defect identification.