97 results about "Waveform correlation" patented technology

The invention provides an identification method for transformer inrush current which belongs to power system main equipment relay protection technology field. The method has characteristics in that the method identifies inrush current and fault current base on waveform correlation degree. By comparison with each sampling point algebraic sum in dynamic differential current short data window, non-saturation region of transformer under inrush current and fault current is searched, two form standard sine waves are constituted of max value and position of sampling data in non-saturation region, then differential current sampling waveform in non-saturation region and two form standard sine waves correlation degrees are calculated respectively, inrush current and fault current are differentiated according with correlation coefficient average. The method can open longitudinal differential protection rapidly when internal fault and no-load closing with fault occur in transformer operation; and can lock longitudinal differential protection reliably when on-load closing occurs inrush current.

A method and an apparatus for detecting a frequency correction burst embedded in a signal which includes ordered samples. The method comprises the following: (a) correlating K sequences of the ordered samples with a predetermined waveform to produce K correlation outputs, each of the K correlation outputs corresponding to one of the K sequences, having a magnitude and being associated with an order index, K being an integer, the predetermined waveform corresponding to the frequency correction burst; (b) storing the K correlation outputs in a buffer according to the order indices; and (c) estimating a parameter based on the K correlation outputs, the parameter indicating detection of the frequency correction burst. The estimated parameter includes a frequency error and an ending time of a frequency correction burst. A quality metric associated with each frequency error is also computed.

The invention discloses a distribution network fault line selection method based on a zero sequence current variable quantity waveform correlation coefficient matrix. According to the distribution network fault line selection method disclosed by the invention, a row off-diagonal element of each feeder zero sequence current variable quantity waveform correlation coefficient matrix and feeders in minimum corresponding before and after switching of a parallel resistance are utilized to carry out line selection for a fault line principle; and zero sequence voltage of a distribution network bus is larger than 15% phase voltage, the parallel resistance is switched by keeping arc suppression coil parameters invariable, a zero sequence current sampling value of each feeder flowing before and after switching of the parallel resistance is measured, the zero sequence current variable quantity waveform correlation coefficient matrix is further calculated, and the row off-diagonal element of each feeder zero sequence current variable quantity waveform correlation coefficient matrix and the feeders in minimum corresponding are selected as fault lines. With the adoption of the method, a line selection result is not influenced by factors such as transition resistance, line parameters, line length, distribution network running mode and fault position, the line selection principle is simple, and the line selection result is high in reliability and strong in practicability.

Improved apparatus and methods for utilizing holographic waveforms for a variety of purposes including communication, ranging, and detection. In one exemplary embodiment, the holographic waveforms are transmitted over an RF bearer medium to provide, inter alia, highly covert communications, radar systems, and microwave data links. The bearer (i.e., carrier) is optionally frequency-hopped, and various pulse modulation techniques applied in order to further increase communications efficiency and covertness including selective shaping of pulses associated with the holographic waveforms. Methods of providing multiple access and high bandwidth data transmission are also disclosed. Improved apparatus utilizing these features; e.g., a wireless miniature covert transceiver / locator, are also disclosed.

A plurality of variables representing the characteristics of a knock is obtained from an output signal of a sensor. The variables include a peak value of the knock frequency component in the output signal of the sensor and a waveform correlation coefficient representing the correlation between the waveform of the output signal and an ideal knock waveform, which is the waveform specific to a knock. The peak value and the waveform correlation coefficient are normalized, and a detection distribution is created using the obtained normalized data values. A correlation coefficient for knock determination representing the correlation between the detection distribution and an ideal knock distribution is calculated. The correlation coefficient for knock determination is compared with a predetermined knock determination threshold value, and the knock determination threshold value is corrected in accordance with the comparison result. As a result, the accuracy and the reliability of knock determination are improved.

A plurality of variables representing the characteristics of a knock is obtained from an output signal of a sensor. The variables include a peak value of the knock frequency component in the output signal of the sensor and a waveform correlation coefficient representing the correlation between the waveform of the output signal and an ideal knock waveform, which is the waveform specific to a knock. The peak value and the waveform correlation coefficient are normalized, and a detection distribution is created using the obtained normalized data values. A correlation coefficient for knock determination representing the correlation between the detection distribution and an ideal knock distribution is calculated. The correlation coefficient for knock determination is compared with a predetermined knock determination threshold value, and the knock determination threshold value is corrected in accordance with the comparison result. As a result, the accuracy and the reliability of knock determination are improved.

The invention provides a microseism event positioning method. The method includes: utilizing a rule that any two waveforms are mutually correlated; calculating pickup first arrival time difference; utilizing weighted stacking of differences between the pickup first arrival difference among all wave detector pairs and calculated first arrival difference as a target function to perform optimized iterative positioning on a microseism event. By the method, the problem that low signal-to-noise-ratio coaxial axis is discontinuous can be effectively overcome; by utilizing weighted stacking of the differences between the pickup first arrival difference among all wave detector pairs and the calculated first arrival difference as the target function, N(N-1) / 2 combinations of wave detectors can be provided for an observation system containing N wave detectors, so that massive information redundancy is provided, and positioning accuracy of the microseism event is improved.

The invention discloses a high precision water level elevation extraction algorithm comprising simulation of a universal waveform; mutual correlation retracing algorithm of the universal waveform and a Level 1b interference waveform; atmosphere and geophysical correction; elevation computation and exclusion of abnormal values; and water level filtering and noise analysis based on SSA. Due to limitation of a satellite altimeter and complex geographical environment, a Cryosat-2 Level 2 altimeter data product has a lot of data losses and precision losses in an inland or nearshore region, the invention improves an altimeter echo waveform retracing algorithm to extract a high precision wave level sequence product, and thus the defect that inland water body or nearshore height measurement data is small in quantity and not high in precision is remedied.

The speech signal fundamental tone period detection method based on waveform correlation method is mainly characterized by using speech collecting system to input the speech signal to be detected into computer and implementing detection of speech signal fundamental tone period in the computer processor. Its detection method mainly includes four steps: 1. pretreatment; 2. speech signal correlated coefficient estimation; 3. after-treatment; and 4. anvoiced sound / voice sound judgement.

The invention discloses a method for measuring permeability of ultra-low permeability rocks under a tri-axial stress effect. The method comprises the following steps of: selecting an ultra-low permeability rock, and preparing a test sample; wrapping water permeable liner plates at the upper end and the lower end of the test sample and the test sample between an upstream porous pressure cushion block and confining pressure chamber base by using a rubber sleeve; applying confining pressure and axial pressure to the test sample to a given value, simultaneously applying permeation pressure to the test sample, and saturating the test sample; after the osmotic pressure saturation of the test sample, applying a sinusoidal pressure wave with a known amplitude and a known frequency to the test sample, recording a downstream pore pressure wave situation, and transmitting the data to a data measurement and acquisition system in real time; changing the confining pressure and the axial pressure, measuring the permeability by using a waveform correlation method, analyzing the permeability of the test sample under different confining pressure and axial pressure situations, and obtaining the permeability under different confining pressure and axial pressure conditions. By adopting the method for measuring the permeability of the ultra-low permeability rocks under the tri-axial stress effect, the weaknesses of the prior art that the measurement precision is poor, only the confining pressure can be provided, and the stress state of the deep rock under the tri-axial stress effect cannot be actually simulated can be overcome.

The present invention discloses a distribution automation master station system single-phase earth fault location method based on transient state recording data. When single-phase earth fault starting criteria is satisfied, a master station system fault location program is started; a received fault recording file is subjected to analysis according to the recording file data format standard; the signal processing technology is employed to calculate and obtain fault characteristic quantities comprising three-phase current catastrophe characteristics before and after fault points, waveform correlation coefficients between each two three-phase catastrophe current and zero-sequence current intrinsic mode energy behind the fault points; the floating-point type fault characteristic quantities obtained through calculation are converted to integrated group numbers, and a group number with the most obvious characteristic quantity is converted to motion signals of a fault indicator; and the interphase short-circuit fault processing mechanism of the distribution automation master station system is employed to complete single-phase earth fault location. The method provided by the invention is not influenced by the system earth mode and the single-phase earth fault condition so as to allow a location effect to be ideal.

The invention discloses a multi-input multi-output radar waveform design and processing method, specifically comprising the following steps: setting waveform parameters according to the resolution power of radar and the zero side lobe band request, and forming a multi-phase sequence matrix; forming the multi-phase encoding sequences of various transmission waveforms by using various lines orderly connected with each other in series in the multi-phase sequence matrix; using the multi-phase encoding sequences connected in series to respectively perform encoding modulation for the base pulse to generate the transmission signals of various transmission array elements of the transmission array; transmitting the generated transmission signals by various transmission array elements; receiving the echo signals of the transmission signals reflected by the target object through the receiving array elements of the receiving array; performing base band conversion and A / D conversion for the echo signals; regarding the transmission signal as the reference signal, and performing pulse compression processing for the echo sequence of various receiving array elements from the frequency domain; and using the scheduled range gate to intercept the pulse pressure output echo sequence according to the stated time interval to limit the interference of the side lobe. The application of the waveform processing method can fully eliminate the interference of the correlative side lobes with different transmission waves in the multi-input multi-output radar pulse compression output signal sequence in the range of the stated distance so that the precise separation for the target scattering information in different observation channels can be realized so as to improve the precision of the following radar signal and data processing.

The invention discloses a reflective trough wave advance detection method for coal roadway excavation along floor or roof of thick coal seam According to the detection method, explosives in a coal seam hole at the position on the head-on tunnel surface of the excavated coal roadway with a distance of 1 / 4 coal thickness from the floor or roof of the coal seam is taken as a shot point for trough wave epicentre excitation, two columns of linearly-arranged detectors are arranged in the coal seam hole at the position on two side coal walls of the excavated coal roadway with a distance of 1 / 4 coal thickness from the floor or roof of the coal seam, and explosion of the explosives is artificially stimulated to generate Rayleigh trough waves propagating into head-on surrounding coal seams of the excavated coal roadway; the reflective Rayleigh trough waves are received by the two detector columns on both sides of the coal roadway, energy and waveform correlation coefficient calculation of the reflective Rayleigh trough waves is carried out, the location of the geological structure interface in the surrounding coal seams of the excavated coal roadway is determined through comparison, so the purpose of the geological structure in the head-on front of the coal roadway and the coal seams at the two sides during excavation along the roof or the floor of the thick coal seam is realized.

The invention is suitable for the field of radar communication, and provides a frequency-based adaptive signal transmission method of a radar system under a frequency interference, a signal transmission system, a radar distance evaluation method and a radar distance evaluation system. According to the method of the invention, at the transmitting end of the radar system, frequency distribution of the interference is obtained through existing spectrum sensing technology; furthermore a frequency point without interference is selected as the carrier frequency of a transmitting signal; at the receiving end, a frequency point signal with a relatively low interference is selected through waveform correlation; and then distance evaluation is performed by means of frequency virtual expansion technology, thereby improving distance evaluation resolution and interference resistance of the system.

An etching apparatus which is able to select a small number of representative wavelengths from waveforms of many wavelengths without setting information on the substance and chemical reaction, and which is able to reduce analysis of etching data which requires many man hours and efficiently set the monitoring / supervision of etching. The etching apparatus is provided with: a lot / wafer / step-wise OES data searching / acquisition function (511) which acquires light emission intensity waveforms along a plurality of etching processing time axes; a waveform change determining function (521) which judges whether there are changes in the plurality of light emission intensity waveforms; a waveform correlation matrix calculation function (522) which calculates a correlation matrix between the light emission intensity waveforms; a waveform sorting function (523) which sorts the light emission intensity waveforms by groups; and a representative waveform selection function (524) which selects representative light emission intensity waveforms from the groups.

The invention relates to an FM / Chirp waveform division multiplex communication method and an application system thereof, belonging to the field of communication. The FM / Chirp waveform segmentation multi-channel communication method is: according to the FM / Chirp composite frequency modulation method, each baseband signal to be transmitted is subjected to carrier modulation, and the frequency domain position overlap, time domain position overlap and waveform mutual correlation degree of the corresponding number of channels are obtained. The modulated carrier is lower than the specified value; demodulate and recover the restored samples of each baseband signal to be transmitted from the synthetic communication signal formed by each modulated carrier through power amplification, attenuation, delay and linear superposition processing, and use each The inter-correlation degree of the modulated carrier waveform of one channel is lower than the specified value to suppress the interference brought by other modulated carriers; the present invention also provides the FCWDM system, FCWDMA system, uplink TDMA / FCWDMA system and downlink TDMA system realized by this method / FCWDMA system. The FM / Chirp waveform division multi-channel communication method and its application system provided by the present invention can realize multi-channel simultaneous transmission at the same frequency, and can use resonance power amplification to realize high-power transmission.

A polar transmitter includes a power amplifier (PA), an amplitude modulation (AM) path including an AM path adjustable delay, an AM path delay measurement circuit, a phase modulation (PM) path including a PM path adjustable delay, and a PM path delay measurement circuit. The AM path delay measurement circuit is configured to measure an AM path delay using waveform correlation, e.g., using peak magnitude events (PMEs) in signals transmitted along the AM path to a power supply port of the PA. The PM path delay measurement circuit is configured to measure a PM path delay using waveform correlation, e.g., using PMEs in signals transmitted along the PM path to a phase-modulated input of the PA. The measured AM and PM path delays are used to adjust the AM and PM path adjustable delays, to reduce the delay mismatch between signals appearing at the power supply and phase-modulated input ports of the polar transmitter's PA.

An ECU obtains two data values (a peak value and a waveform correlation coefficient) that show the characteristics of a knock from the output of a knock sensor. The ECO approximately obtains the mean of each data value by smoothing each data value, and approximately obtains a variance by smoothing the squared deviation between the data values before and after the smoothing process. The ECU then computes the square root of the variance to approximately obtain a standard deviation. The ECU normalizes each data value using the mean and the standard deviation, obtains a distribution of the normalized two data values, and calculates a correlation coefficient that shows the correlation between the obtained distribution and an ideal knock distribution. Based on the correlation coefficient, the ECU corrects a knock determination threshold value. Therefore, the mean and the standard deviation of the data values are computed with a small RAM capacity.

The invention discloses a laser ultrasonic transmission type time-delay detection method for internal defects of a material. The method comprises the following steps: firstly, enabling pulse laser excited by a laser device to act on the surface of a sample so as to excite ultrasonic body waves; secondly, focusing detection laser on a centering position of excited laser so as to detect ultrasonic body wave signals; thirdly, scanning a two-dimensional moving sample, and carrying out mutual correlation calculation on ultrasonic wave signals obtained at all scanning points by taking ultrasonic bodies with relatively high signal to noise ratios at non-defect position of the sample as reference waves; and finally, calculating the waveform correlation coefficients of the ultrasonic wave signals and time delay values of waveforms with the highest correlation coefficients, so as to finish the detection of the internal defects. The method has high sensitivity and stability to the detection of the internal defects, particularly sub-millimeter microdefects, the accurate positioning and quantification of the internal defects can be realized, and the method is suitable for nondestructive testingof various materials.

The invention discloses a power distribution network line-transformer relationship anomaly identification and judgment method, which comprises the following steps of distribution transformer voltage noise processing based on abnormal value detection, voltage acquisition point waveform curve stability calculation based on a sliding window algorithm, three-phase imbalance neutral point offset reduction based on a reduction method, a Pearson-correlation-coefficient-based voltage curve calculation method for judging the similarity degree of voltage curves, topological anomaly clustering based on ahierarchical clustering method, and fault determination. On the basis of massive operation data of a centralized power grid, the operation situation of a topological structure is reflected by researching and utilizing service characteristics of voltage waveform similarity through a distribution transformer voltage waveform hierarchical clustering method, and a standing book and power grid topological data are accurately identified; on the basis of a voltage curve waveform correlation coefficient, hierarchical clustering is used to realize accurate identification of the topological structure,and the accuracy and authenticity of the topological structure of the power distribution network are comprehensively improved; and through secondary comparison, the fault type is quickly determined.

The invention discloses a distribution network fault locating method based on transient waveform correlation. After a fault occurs, S-transform is carried out on transient waveform information, a time-frequency matrix is constructed, similarity calculation is carried out on the same and time-frequency matrices in all branch sample libraries, and a fault branch is determined according to similarityof an actual fault transient waveform and the branch sample libraries; and a proportional relationship of overall wave amplitude deviation and fault point distance is used to calculate a fault pointlocation. Simulation analysis shows that in different fault conditions, the method can always reliably locate fault point locations, and has higher locating accuracy.

Provided is an excitation surge current identification method based on a support vector classifier. The method selects seven characteristics of a secondary second harmonic, a third harmonic, a current dead angle, a wave width, a waveform distortion amount, a waveform correlation coefficient and an excitation side measured impedance as inputs of a support vector machine, then various running states of a transformer are trained, and a decision function identifying an excitation surge current and a fault current is constructed. When the transformer is out of order, data collected by a protection device collection system is calculated to obtain seven characteristics, the seven characteristics are put into the decision function and determination of an excitation surge current and a fault current is carried out. The identification method integrates advantages of principles of harmonic wave braking, a dead angle, waveform similarity and the like and avoids respective limitation, and the surge current identification credibility is raised. An algorithm can be converted into a convex optimization problem finally, and the local minimum problem which cannot be solved by a neural network is avoided. The method is free from a transformer wiring mode and is free from model parameters, the applicability is strong and the flexibility is good.

The invention relates to a satellite passive orbit measurement method and system, and relates to satellite technology. The satellite passive orbit measurement method of the present invention is to passively receive the radio signal broadcast by the satellite through the ground station, so as to realize the position measurement and orbit measurement of space objects such as satellites. The specific method is to set up 2 to 4 antennas in each measurement station, and use carrier signal waveform correlation to obtain the range difference D between the two antennas when receiving satellite signals. The rendezvous measurement model obtains the position and orbit of the satellite in space. While completing the above-mentioned rough orbit determination, 10-100 satellite position accuracy monitoring reference stations shall be established within the coverage area of ​​satellite signals. The vector correction number of the satellite position is obtained, so as to achieve the second high-precision orbit determination of the satellite.

The invention discloses a waveform correlation-based distance protection method under a distributed parameter model. The method includes the following steps that: break variable current is adopted as a protection startup component, and whether a fault occurs on a line is judged, and protection is started; waveform correlation coefficients rho 0.6D and rho D of fault voltage and fault component current at 60% and 100% of the line are calculated through utilizing voltage and current sampling values where protection is installed and combining with fault phase selection results when a fault phase is under a power transmission line Bergeron; and whether rho 0.6D and rho D satisfy the expression rho D<=rho 0.6D is judged, if rho 0.6D and rho D satisfy the expression, the fault is an intra-region fault, protection action trips, otherwise, the protection does not act. The method of the invention is based on a power transmission line distribution parameter model, so that the method is not affected by line distribution characteristics; fault voltage and fault component current are utilized to form time domain protection criterions, and filtering is not required, and transition resistance-withstanding ability is strong; and the fault can be judged as long as the waveform correlation coefficients of voltage and current of two points at the tail end of the line are judged, and therefore, calculation amount is small.

A method and an apparatus for optimizing switching operations executed by a switching device coupled to an AC power line, wherein signals related to the waveform of the electrical phases of the power line are acquired. When a command for executing a switching operation on one of the electrical phases is issued, the signals acquired are stored. Based on the signals stored, data indicative of the severity of switching transients occurred during the executed switching operation and second data indicative of the time occurred for the executed switching operation are calculated and correlated to each other. Based on the data calculated, it is determined whether a parameter representative of a target point on the waveform for executing future switching operations substantially synchronous with the waveform has to be adjusted.

Detecting timing of a synchronization sequence included in a data stream transmitted in a noisy channel. The synchronization sequence is a known data sequence purposely injected into the data stream for synchronization. A data stream waveform, is obtained from a noisy communication channel. The data stream waveform includes an instance of a synchronization sequence waveform. One or more samples of the synchronization sequence waveform are obtained. One or more samples of a model synchronization sequence waveform are obtained. The model synchronization sequence waveform models an expected waveform for the synchronization sequence being transmitted on the communication channel by applying the synchronization sequence to a model of the communication channel. The instance of the synchronization sequence waveform is correlated with the model synchronization sequence waveform by correlating one or more samples of the synchronization sequence waveform with the one or more samples of the model synchronization sequence waveform.

The invention relates to a micro-seismic migration imaging positioning method based on multiplication of waveform cross correlation coefficients, and belongs to the technical field of oil-gas reservoir fracture micro-seismic monitoring. The method includes the following steps of: preprocessing actual micro-seismic data; performing subsurface imaging point division, and calculating the travel timeof all imaging points to each receiving point on the ground; for a certain imaging point, eliminating the arrival time difference of the imaging point to different receiving points, calculating the cross-correlation coefficient of a micro-seismic record after the time difference correction; calculating the cross-correlation energy value E of the imaging point; repeating the third and fourth stepsto obtain the energy values E of all underground imaging points; and setting an energy threshold E0, obtaining the imaging point position of an energy maximum value greater than the energy threshold as the occurrence position of a micro-seismic source. The method realizes the dual-effect suppression of the noise by using the form of multiplication of the waveform cross-correlation coefficients soas to greatly improve an anti-noise capability, avoids the interference of the first arrival polarity on the positioning imaging results, has high calculation efficiency and satisfies the real-time monitoring of the micro-seism.