154 results about "Reflectometry" patented technology

A method for retrieving tropospheric wet delay and atmospheric water vapor content over polar sea ice with TDS-1 satellite grazing angle spaceborne GNSS-R is provided, including: Si, obtaining TDS-1 GNSS-R raw intermediate frequency signal data, VMF3 grid data, GPT3 grid data and ERA5 data; S2, correcting an error of tropospheric wet delay estimation of grazing angle spaceborne GNSS-R; S3, constructing a grazing angle spaceborne GNSS-R tropospheric wet delay estimation model; S4, calculating grazing angle spaceborne GNSS-R ZWD; S5, calculating a Tm value of a target point based on GPT3 model, substituting the Tm value into a conversion factor II, and combining calculated GNSS-R ZWD to obtain a GNSS-R IWV estimated value; and S6, verifying inversion performance of GNSS-R ZWD and integrated water vapor (IWV) by using reference data.

Provided is a detection method of spaceborne GNSS-R original intermediate frequency coherent reflection signals in ocean, polar and inland water areas, including: acquiring spaceborne GNSS-R original intermediate frequency signal data of TDS-1 or CYGNSS and preprocessing the data; selecting coherent detection feature engineering; setting data labels of different scenes and coherent and incoherent reflected signals; dividing a training set and a test set; and training and testing a multimode-oriented hybrid model for coherent and incoherent detection and classification of spaceborne GNSS-R signals, using the training set to train a model, applying a trained detection model to a test data set, and comparing and evaluating obtained detection results with a classical coherent detection algorithm.

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 discloses a method for detecting the strain of a key part of a wind turbine generator based on a temperature compensation OFDR demodulation weak fiber bragg grating array, and relates to the technical field of wind turbine generator detection, and the method comprises the steps: installing a weak fiber bragg grating sensor array at the key strain part according to the structural characteristics of the wind turbine generator, a temperature reference grating is arranged in the non-strain area or the constant-temperature area so as to monitor the temperature change in real time; a tunable laser, an optical fiber coupler and a photoelectric detector are utilized to construct an optical frequency domain reflection demodulation system, and system calibration is completed; based on an optical frequency domain reflection demodulation system, reflection spectrum signals are collected, the relation between wind turbine generator strain and temperature change is analyzed through a temperature compensation mechanism, and strain information of key parts of the wind turbine generator is obtained. According to the method, the accuracy and reliability of strain detection are effectively improved, and the problem of measurement errors caused by neglecting the influence of temperature change in a traditional method is solved.

The invention belongs to the technical field of soil research equipment, and aims to solve the problem of measurement errors when a time domain reflection device is used for measuring the ice content of soil. The invention provides a method and a device for testing the ice content of a soil body based on an electrochemical impedance modulus value. The method comprises the following steps: setting test parameters of the ice content of the soil body through an electronic computer; a temperature control device is used for adjusting and controlling test conditions of the soil body sample, and a control module drives the temperature control device to perform stepped cooling on the soil body sample; applying a disturbance signal to the soil body sample through the test module, and synchronously collecting a response signal sent by the soil body sample; calculating an experimental value of an electrochemical impedance module value by using electrochemical impedance data analysis software, fitting by combining with the temperature signal to obtain a fitting value of the electrochemical impedance module value, and substituting the value and the initial water content into a soil mass ice content calculation model to obtain the ice content of the soil mass sample. According to the invention, the ice content of the soil body can be rapidly and accurately calculated based on the chemical-electrochemical impedance modulus value.

The invention discloses a soil nitrogen leaching capacity monitoring method based on a frequency domain reflectometry, and relates to the technical field of soil water environment monitoring, in particular to a nitrogen leaching online monitoring method based on the frequency domain reflectometry (FDR), the Darcy law and a Van Genuchten (VG) model. And a monitoring method with high precision and sensitivity, multi-parameter synchronous detection and low cost is provided for the soil nitrogen leaching capacity. Comprising the following steps: 1, collecting and pretreating a soil sample; 2, placing the treated soil sample in a soil experiment cylinder; 3, inserting the multi-parameter sensors into the soil experiment cylinder in a layered manner; 4, 1000 ml of water is injected, and data acquisition is carried out; and 5, realizing soil nitrogen leaching capacity monitoring in combination with a Darcy law and a VG model.

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.

The invention discloses a fault repairing method of a server single board and electronic equipment, and relates to the field of server hardware reliability, and the method comprises the steps: scanning a plurality of target signal links of the server single board through a time domain reflectometer, correspondingly comparing the new impedance value and the new reflection waveform characteristic in the scanning result with the initial impedance value and the initial reflection waveform characteristic, determining at least one fault link of the server single board when the comparison result is inconsistent, and performing multi-modal analysis by combining the operation state data of the server single board. And determining the fault level of at least one fault link in the server single board and correspondingly generating a fault repair strategy to switch the fault link to the standby link, thereby solving the problems of single detection dimension, complex fault monitoring blind area, high-frequency signal monitoring failure and the like in the related technology, and improving the detection accuracy. Through time domain reflectometer monitoring, multi-modal data fusion analysis and redundancy switching, fault prediction, accurate positioning and lossless self-repairing of a server single board target signal link are realized.

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 computer-implemented method for training an artificial intelligence model configured to characterize a fault on a transmission line, the method comprising the steps of: Receiving (501) a set of signals constituting a training signal base of the model, each signal corresponding to a simulation or measurement of a compressed reflectometry signal for a transmission line having a fault characterized by an impedance and / or a position, A compressed reflectometry signal resulting from the execution of the steps of: Injecting a predefined reflectometry signal into the transmission line, Carrying out a compressed acquisition of said signal comprising at least the multiplication of said signal taken from the line by a predefined pseudo-random sequence,Train (502) the artificial intelligence model from the training signal base to perform at least one task among: a task of classifying a type of fault present on the line, a task of predicting the position and / or the impedance of a fault present on the line. Figure 5,

The thickness of the film stack of the workpiece and the composition of the film stack are determined using x-ray technology, spectroscopic ellipsometry (SE) and / or spectroscopic reflectometry (SR) and multi-wavelength Raman spectroscopy. The measurements are combined to form combined measured data. The combining includes regressing the second measurement and the third measurement. The combined measured data is then used to determine the thickness of the film stack and the composition of the film stack.

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.

The invention relates to a method for determining an optical reflectivity of a curved surface (3) of an optical test object (2), in particular a mirror or lens, wherein the reflectivity (R) is determined using a reflectometer (4), in particular an EUV reflectometer, which comprises a light source (5) and a light sensor (6), and wherein, in order to determine the reflectivity, a light beam (7) from the light source (6) reflected on the surface (3) is captured by the light sensor (6) at least at a predetermined distance from the test object (2). According to the invention: the light sensor (6) is displaced at least once for a calibration process such that the reflected light beam (7) is captured at varying distances (x) from the surface (3) of the test object (2), and a reflectivity (R) is determined for each distance (x); and a baseline reflectivity of the surface (3) is determined depending on the captured reflectivities (R).

In an aspect, a user equipment (UE) may receive a reflectance schedule associated with a reconfigurable smart surface (RIS), where the reflectance schedule indicates one or more incident-reflectance angle pairs and an indication of a time at which the one or more incident-reflectance angle pairs are activated at the RIS. The UE may transmit one or more sensing signals for reflection by the RIS based on the reflection schedule, wherein the one or more sensing signals are transmitted at one or more occasions during which at least one of the one or more incidence-reflection angle pairs that reflects the one or more sensing signals from the RIS to the target area is activated.

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 application discloses a kind of distance gating anti-interference optical frequency domain reflection distributed measuring device and method, its device includes frequency-sweeping laser light source, first optical coupler, Mach-Zehnder modulator, circulator, detection optical fiber, polarization controller, second optical coupler, balanced photodetector and data measurement unit.Wherein, Mach-Zehnder modulator is configured as using pseudo-random spread spectrum coding technology to the input probe light is BPSK modulation.Through the above device and method, the application successfully solves the contradiction between long distance measurement and fast frequency sweep in traditional OFDR difficult to obtain.

Methods and systems for referencing an optical power loss measurement (OPLM) system, and methods and systems for measuring an optical insertion loss of an optical device under test (DUT) using an OPLM system referenced as such. The herein-provided reflectometric one-cord referencing method combines the capabilities of an OPLM system with that of an Optical Time Domain Reflectometer (OTDR). A first test unit comprises an optical source that is used as the light source in the OPLM. A second test unit comprises a power meter which is used as the power meter in the OPLM measurement. Either the first or the second test unit comprises an OTDR acquisition device. The reflectometric one-cord reference measures the connector loss along the reference link using OTDR capabilities of the test unit(s). Once the power reference of the OPLM devices is obtained, the reflectometric one-cord reference method may determine the optical insertion loss of the DUT while eliminating the measured connector loss.

The invention discloses a method and system for measuring the dielectric constant of a material, and the method comprises the steps: enabling a terahertz pulse signal to flow through a transmission line and generate reflection through growing a coplanar waveguide transmission line on the surfaces of an electro-optical crystal and a measured material; after femtosecond laser is processed, a terahertz signal is sampled, an optical polarization state analysis system reproduces an electric signal and extracts a peak moment, and a relative dielectric constant is calculated by combining transmission line structure parameters and a formula. According to the invention, electro-optical sampling and time domain reflection technologies are combined, high time resolution and structure adaptability are realized, and accurate measurement of the dielectric constant of the material is realized.

The present invention provides a noise-suppressed, loop-reference-structure frequency-division-multiplexed optical frequency domain reflectometer, belonging to the field of optical fiber testing. The device comprises a tunable laser source module, a main interferometer test module, an auxiliary interferometer module, a signal acquisition and analysis module, and a ring cavity frequency-division-multiplexing module. The device is characterized in that the ring cavity frequency-division-multiplexing module employs a ring cavity structure. After light is input into the ring cavity, a portion of the light is directly output, while the other portion circulates in the ring cavity before being output. Multiple cycles generate reference light with different time delays, which interfere with the test light. In a single laser scan, multiple groups of beat frequency signals are collected. After frequency sweep nonlinearity correction and frequency domain conversion, signal intensity correction and segmented interception are performed to achieve frequency division multiplexing of the optical signal in a single scan. After averaging processing, the signals are integrated into a group, effectively improving the sensitivity of optical frequency domain reflectometry measurements of short-distance optical fiber devices, suppressing noise influences, and maintaining a compact structure.

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.

Methods and systems for image measurement of semiconductor structures based on combined spectral reflectance measurement (SR) and pattern recognition (PR) at high throughput are presented herein. Large pitch targets and thick targets throughout a die are measured with improved fringe contrast, resolution, and spectral fidelity. The PR-based imaging subsystem generates illumination light in a range from visible light to short infrared wavelengths. The SR subsystem generates illumination light in the range from deep ultraviolet to short infrared wavelengths. The SR subsystem includes low numerical aperture (NA) optics to achieve relatively large size illumination and collection of light spots. The SR subsystem and the PR-based imaging subsystem share the same objective lens and distinguish signals from different depths of a measured structure. In some embodiments, a combined machine learning-based measurement model estimates values of one or more parameters of interest based on both SR and PR image signals.