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32 results about "Bluestein's FFT algorithm" patented technology
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The chirp Z-transform (CZT) is a generalization of the discrete Fourier transform (DFT). While the DFT samples the Z plane at uniformly-spaced points along the unit circle, the chirp Z-transform samples along spiral arcs in the Z-plane, corresponding to straight lines in the S plane. The DFT, real DFT, and zoom DFT can be calculated as special cases of the CZT. Specifically, the chirp Z transform calculates the Z transform at a finite number of points zₖ along a logarithmic spiral contour, defined as: Xₖ=∑ₙ₌₀ᴺ⁻¹x(n)zₖ⁻ⁿ zₖ=A·W⁻ᵏ,k=0,1,…,M-1 where A is the complex starting point, W is the complex ratio between points, and M is the number of points to calculate.
Stable underwater communication node awakening signal detection method
ActiveCN105472719AExtended service lifeHigh frequency resolutionPower managementTransmissionUnderwater wireless sensor networksFrequency interval
The invention discloses a stable underwater communication node awakening signal detection method. The stable underwater communication node awakening signal detection method comprises the following steps of: S1, emitting a dual-frequency or multi-frequency awakening signal; S2, according to a set initial frequency, transform point number and frequency resolution ratio, executing CZT (chirp z transform) on a unit circle on the awakening signal; S3, searching an extreme value of a zoom spectrum of CZT, judging a signal as the awakening signal if an estimated relative frequency interval and relative amplitude relationship between frequency components are kept unchanged, or judging the signal is not the awakening signal; and S4, after the signal is determined as the awakening signal, powering on an integral communication node to enable the node to be transferred into a working state, and when the node completes working, cutting off a power supply to enable the node to be transferred into a sleeping state. According to the stable underwater communication node awakening signal detection method disclosed by the invention, due to the high frequency resolution ratio, multiple groups of frequencies can be adopted for combination to awaken a plurality of nodes of an underwater sensor network without worrying about mutual interference, so that detection false-alarm is greatly reduced and a service life of the underwater wireless sensor network is prolonged.
Owner:HARBIN ENG UNIV
Circular synthetic aperture radar imaging method
InactiveCN106772380AHigh resolutionHigh resolution imagingRadio wave reradiation/reflectionInformation processingRapid imaging
The invention discloses a circular synthetic aperture radar imaging method, belonging to the technical field of electronic signal processing. The invention relates to a spatial remote sensing and air-to-ground observation information processing technology, in particular to an onboard circular synthetic aperture radar imaging technology. According to the imaging method, an original oblique plane echo is mapped to the ground plane by solving the inverse of a system kernel function, and the distribution of signals in a wave number domain is obtained by multiplying an azimuth frequency domain with a reference function, so that plane wave approximation is avoided, the problem that the size of an imaging area of the traditional polar format algorithm is limited can be solved, and the imaging of a large imaging scene can be realized; pseudo-polar coordinates are used for replacing rectangular coordinates as an intermediate interpolation transition matrix, and the distribution density characteristic of the signals in the wave number domain is considered, so that the interpolation precision is higher, the obtained image resolution is higher, and the high resolution imaging can be realized; the imaging process only involves one-dimensional interpolation, and fast algorithms such as chirp z transform (CZT) and inverse fast Fourier transform (IFFT) are adopted, so that the method has very high computational efficiency and can realize rapid imaging.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA
Method for acquiring parameters of electric power harmonic waves by using Hanniing window function continuous frequency spectrum interpolation
InactiveCN102331526AComputing speed advantageSpectral/fourier analysisFrequency spectrumHarmonic analysis
Owner:CHINA UNIV OF MINING & TECH
FPGA (field-programmable gate array)-based moving target radar cross section measurement method
InactiveCN108169727ASimple structureClear structureWave based measurement systemsHardware structureTheoretical methods
The invention belongs to the radio measurement technical field and relates to an FPGA (field-programmable gate array)-based moving target radar cross section measurement method. According to the FPGA(field-programmable gate array)-based moving target radar cross section high-precision measurement realization method, a conventional frequency domain pulse compression hardware structure is improvedin a distance domain, so that a buffer-based frequency domain pulse compression hardware structure can be realized; the theoretical method described in the background art can be realized with only onemultiplying unit adopted; and a new moving target detection and chirp-z transformation combined hardware structure is proposed in the Doppler domain. The method of the invention has the advantages ofclear module structure, high IP multiplexing degree, simple hardware structure, high measurement accuracy, high processing speed, high real-time performance and low power consumption.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA
Method for obtaining continuous frequency spectrum interpolation power harmonic parameter of Nuttall window function
InactiveCN102253282AComputing speed advantageSpectral/fourier analysisFast Fourier transformFrequency spectrum
The invention discloses a method for obtaining continuous frequency spectrum interpolation power harmonic parameter of Nuttall window function, and is suitable for harmonic analysis and monitoring of voltage and current of power grid. The method comprises the following steps: performing chirp Z transform (CZT) to extract a fundamental wave signal parameter (amplitude, frequency and phase) at high precision from a power signal containing harmonic; subtracting the fundamental wave signal from the analyzed power signal and adding a cutoff power signal of Nuttall window function, and calculating the frequency spectrum of the residual signal by FFT (fast Fourier transform); calculating the frequency value of each harmonic accurately according to the frequency of the fundamental wave; and finally, interpolating the Nuttall window function in the frequency domain according to the frequency of each harmonic, and accurately calculating the parameter of each power harmonic. The method disclosed by the invention has basically equivalent estimation precision as the method for analyzing power harmonic through FFT double-spectral-line interpolation fitting with Nuttall window, while the calculation quantity is about half of the latter one.
Owner:CHINA UNIV OF MINING & TECH
Electric energy quality mixing detection method
InactiveCN105223434AImprove real-time performanceReduce computationElectrical testingPower qualityLow frequency band
The invention discloses an electric energy quality mixing detection method. The method comprises the following steps of using an inter-harmonic detection method based on a complex modulation refinement spectrum analysis method to detect interharmonics in a power grid; using a voltage fluctuation demodulation method to measure voltage fluctuations in the power grid; and using a flicker measurement method based on chirp Z transform to measure flickering in the power grid. An electric energy quality detection operand is reduced, real-time performance of inter-harmonic detection is increased and a flicker measurement error is eliminated maximumly. The chirp Z transform is used to calculate a frequency and an amplitude of a fluctuation component. An disadvantage that the flicker detection has a large error in a low frequency band is overcome. An effective support is provided for electric energy quality detection result correctness.
Owner:ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID QINGHAI ELECTRIC POWER COMPANY
Imaging method of synthetic aperture radar in large squint angle mode
InactiveCN103576147AImprove computing efficiencyEfficient resultsRadio wave reradiation/reflectionFrequency spectrumSynthetic aperture sonar
The present disclosure provides an imaging method for a Synthetic-Aperture Radar (SAR) in a high squint mode. The method includes: perform perturbation function multiplication for an echo signal in the azimuth Doppler domain-range time domain to eliminate the dependence of an echo signal quadratic azimuth-range coupling factor on the change of a target slant range; perform reference function multiplication in the two-dimensional frequency domain, wherein the reference function is a conjugate function of a point target echo spectrum at a reference slant range; complete compensation of all phases, which do not vary with the range, of a two-dimensional spectrum through the multiplication of the two-dimensional spectrum and the reference function; rectify the differential range migration factor of the echo signal in the two-dimensional frequency domain by utilizing Chirp-Z transform, complete range migration rectification by performing convolution once and phase multiplication twice; compensate an azimuth residual phase through the azimuth phase multiplication, and perform azimuth compression to obtain a focused SAR image. The method of the present disclosure can perform highly efficient and precise imaging for high squint SAR data.
Owner:INST OF ELECTRONICS CHINESE ACAD OF SCI
Linear chirp z transform based frequency offset estimation algorithm in M-QAM (M-ary Quadrature Amplitude Modulation) coherent optical communication system
InactiveCN102355305AReduce operational complexityHigh precisionMulti-frequency code systemsElectromagnetic receiversFrequency spectrumQam modulation
The invention provides a linear chirp z transform based frequency offset estimation algorithm in an M-QAM (M-ary Quadrature Amplitude Modulation) coherent optical communication system, which comprises the following steps that: a smaller amount of M-QAM signal receiving sample values are selected for four-power; the FFT (Fast Fourier Transform) is conducted to obtain a frequency corresponding to the maximum spectral value to be recorded as a roughly estimated value; the linear CET (Chirp z Transform) of four-power signals is conducted near the roughly estimated value to obtain a frequency corresponding to the maximum spectral value; and the frequency is divided by four to obtain a frequency offset estimated value of M-QAM signals. The linear chirp z transform based frequency offset estimation algorithm does not adopt a gradient descent method, a Newton method and other methods depending on a step size and the number of symbols, but adopts a method that the frequency is finely estimated by CZT with a fixed computation load. Since the CZT can be realized by the FFT with fast algorithm, the complexity of the algorithm can be obviously reduced in the algorithm, and meanwhile, the algorithm is applied to all-order QAM signals.
Owner:BEIJING UNIV OF POSTS & TELECOMM
Synchronization method of carrier frequency and communication equipment in digital communication system
At sending end, training symbols are inserted into every other section of digital modulated communication signals and then the signals are sent. The training symbols are composed of special impulse function sequence in frequency domain. At receiving end, FFT transforms received training symbols to frequency domain. In frequency domain, after training symbols are multiplied by conjugate symbols of the training symbols, result is divided into multiple sections with identical length, then corresponding weight factors are assigned to each section, and multiple sections are superimposed as one section. Chirp-Z transform and interpolation operation are carried out for the data in the one section so as to obtain position of maximum amplitude. Frequency shift is evaluated from formula fe=fs(omega-K / 2) based on position of maximum amplitude. fe controls oscillation frequency of oscillator to reach frequency synchronism.
Owner:ALCATEL LUCENT SHANGHAI BELL CO LTD
System and method for symbol rate estimation using vector velocity
InactiveUS20080101480A1Secret communicationData rate detection arrangementsFast Fourier transformFrequency spectrum
A system and method for symbol rate estimation using vector velocity that does not require any prior knowledge of the signal's structure and is accurate in the presence of frequency offset and noise. An input signal is converted to a symbol constellation path signal, and a velocity signal representing a velocity of the symbol constellation path signal is generated. A first frequency spectrum of the velocity signal is generated by performing a Fast Fourier transform on the velocity signal, and a maximum peak value of the first frequency spectrum, a first bin below the maximum peak value, and a second bin above the maximum peak value are identified. A Chirp-Z transform is performed on the velocity signal using the first bin and the second bin as coefficients, wherein performing the Chirp-Z transform generates a second frequency spectrum including only frequencies within the range of the first bin and the second bin, and wherein the second frequency spectrum presents a higher resolution than the first frequency spectrum. A maximum peak value of the second frequency spectrum is identified, wherein the maximum peak value of the second frequency spectrum corresponds to the symbol rate of the input signal.
Owner:L 3 COMM CORP
A fast placement method for large-scale ultra-sparse planar arrays with controllable minimum pitch
ActiveCN109214088AIncrease freedomReduce fill factorAntenna arraysHigh level techniquesFill factorArray element
The invention discloses a large-scale ultra-sparse plane array rapid layout method with controllable minimum pitch, the layout method is divided into two steps: initial optimization with unlimited minimum spacing and correction optimization with limited minimum spacing. S01: in the initial optimization, array layout with dense grid is adopted, array element excitation is randomly initialized, anda fast synthesis array optimization algorithm with grid spacing not equal to half wavelength is proposed, i.e., iterative Chirp-Iterative Chirp-z transform (ICZT); on this basis, the improved ICZT isproposed to synthesize low sidelobe level, and the concept of filling factor is introduced to reduce the number of array elements gradually to achieve the purpose of sparse array, and the condition ofiteration termination is improved to obtain the array layout with the lowest sparse rate as far as possible. S02: in the correction optimization, the concept of discarding exponent is proposed, and the array element is discarded to satisfy the constraint of array element spacing. The invention completes the fast layout of a large-scale ultra-sparse planar array with controllable minimum pitch.
Owner:XIAMEN UNIV +1
Polar coordinate format imaging method for bistatic forward SAR of mobile platform
The invention discloses a polar coordinate format imaging method for the bistatic forward SAR of the mobile platform, comprising the following steps: transforming the parallelogram wave spectrum support domain of MP-BFSAR into a horizontal quasi-rectangular shape using a wave spectrum support domain affine transformation method; then realizing the re-sampling from a wave spectrum distance vector polar coordinate to a cartesian coordinate by a direction vector chirp-z transformation; performing a distance compression and a scene center motion compensation; realizing the re-sampling from a wavespectrum direction vector polar coordinate to a cartesian coordinate by using a method of accumulating a upsampling map in the direction vector; performing a two-dimensional inverse Fourier transformto obtain a coarse imaging result; and obtaining a final imaging result by defocus correction. The utilization of the wave spectrum collected by the present invention is significantly improved compared to the prior art methods.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA
Digital watermark detection device and digital watermark detection method, as well as tampering detection device using digital watermark and tampering detection method using digital watermark
A digital watermark detection device includes a first chirp z-transform unit (202a) and a second chirp z-transform unit (202b) for estimating the cochlear delay characteristics simulated by cochlear delay filters that were used in embedding digital watermark data in an acoustic signal. The digital watermark data embedded in the acoustic signal is detected based on the cochlear delay characteristics estimated in accordance with the result of chirp z-transform applied by these first chirp z-transform unit (202a) and second chirp z-transform unit (202b).
Owner:JAPAN ADVANCED INST OF SCI & TECH
Method and system for performing real-time spectral analysis of non-stationary signal
A method is provided for performing real-time spectral analysis of a non-stationary signal. The method includes sampling the non-stationary signal, using an observation window having a length short enough to approximate a stationary signal, to provide an initial set of sampled data, buffering the initial set of sampled data to obtain multiple buffered sets of sampled data, filtering the initial set of sampled data and the buffered sets of sampled data, using corresponding filter responses, to obtain multiple filtered sets of sampled data, and performing a chirp-z-transform (CZT) of the filtered sets of sampled data to provide a set of discrete Fourier transforms (DFT) coefficients. A total signal spectrum of the non-stationary signal is reconstructed using the set of DFT coefficients.
Owner:KEYSIGHT TECH
Method and equipment for carrier frequency synchronization
InactiveCN1520081AExact searchSimple structureSynchronisation information channelsSynchronisation signal speed/phase controlCommunications systemFourier transform on finite groups
The method includes following steps and devices. At sending end, specific PN sequences are inserted into every other section of digital modulated communication signals and then the signals are sent. PN sequence is C=(v X u). At receiving end, matched filtering is carried out for baseband signal containing PN sequence with frequency being converted so as to output P pieces of signals in complex number. Using likelihood function and FFT transforms the said complex signals to frequency domain, from which coarse position omega 0 of max. amplitude is found. Using Chirp-Z transform finds position increment information omega1. quadratic interpolation is carried out for omega1 to obtain position increment omega, which is exact position of max. amplitude. Frequency shift fe is calculated from formula fe=fs.(omega+omega0 - M.P / 2) / K.M.P. fe controls oscillation frequency of oscillator to reach frequency synchronism. The invention also includes receiver and transmitter for implementing the method.
Owner:ALCATEL LUCENT SHANGHAI BELL CO LTD
LS (Least Square) based phase information calculating method in complex environment
The invention discloses an LS (Least Square) based phase information calculating method in a complex environment. The method comprises the following steps of simultaneously calculating by adopting short-time chirp-z transform, obtaining signal frequencies, at different moments, of a reference channel through a selected amplitude maximum method and calculating and extracting multiple signal frequencies, exceeding a detection threshold, at the different moments, of the reference channel by adopting a short-time multi-target frequency detection algorithm; and calibrating actual signal frequencies, at the different moments, of the reference channel by adopting a matching discrimination method, which particularly comprises: calculating phase values, corresponding to frequency values of the reference channel at the different moments, of different receiving channels by adopting an LS method. By using the method provided by the invention, the frequency of a useful signal is extracted from a disorderly signal frequency spectrum; a disorderly frequency spectrum brought by random noise and clutter is abandoned; by utilizing the signal frequencies obtained by discriminatory analysis, a mathematic model between an observed signal and a signal initial phase is constructed; and next, the information of the signal initial phase of the corresponding receiving channel is calculated and obtainedby adopting an LS algorithm, so as to be called by other application of target location and the like.
Owner:NANJING CHANGFENG AEROSPACE ELECTRONICS SCI & TECH
Wavelength tag information analysis device and analysis method
ActiveCN102611520AOvercome inaccuraciesWavelength-division multiplex systemsElectromagnetic transmissionInformation analysisFrequency spectrum
The invention discloses a wavelength tag information analysis device and an analysis method. The received sampling signals are subjected to chirp-Z transform (CZT) analysis continuously by J times by a logic processing unit, and the frequency-related information of the continuous J times of each wavelength tag frequency in the sampling signals is counted to resolve wavelength tag information, wherein J is an integer larger than zero. Based on the characteristic of CZT that can select an arbitrary start frequency and frequency resolution (or stop frequency), the device and method provided by the invention can realize spectral zooming during frequency analysis by subjecting the sample signal to Z transform, thereby obtaining higher start frequency resolution, and reducing frequency measurement error caused by picket fence effect.
Owner:ZTE CORP
Rapid sea wave simulation method based on Chirp Z transform
InactiveCN102141612AReduce computationReduced simulation timeWave based measurement systemsSpecial data processing applicationsFrequency spectrumSea waves
The invention belongs to the technical field of ocean remote sensing and relates to a rapid sea wave simulation method based on Chirp Z transform. The method comprises the following steps: calculating a one-dimensional sea wave frequency spectrum by virtue of wind speed; converting the one-dimensional sea wave frequency spectrum into a sea wave frequency direction spectrum; converting the sea wave frequency direction spectrum into a two-dimensional sea wave number spectrum; and simulating fluctuation of sea wave by carrying out Chirp Z conversion on the two-dimensional sea wave number spectrum for twice. Compared with the prior art, the method provided by the invention has the advantages that the computation amount can be effectively reduced, and the simulation time is saved.
Owner:BEIJING INSTITUTE OF TECHNOLOGYGY
Signal Processing Method of Vehicle Forward Collision Avoidance System
ActiveCN105445714BMeet high precision requirementsRealize functionRadio wave reradiation/reflectionFast Fourier transformPeak value
The invention discloses an automobile forward direction anticollision system signal processing method. In each frequency sweep cycle, the following processes which are performed on upper sweep frequency IQ data and lower sweep frequency IQ data of each channel comprise steps of performing fast Fourier transform FFT on N points of IQ data, performing adaptive threshold detection on transformed plural module value data after transmission, outputting an over-threshold point position, taking an interval between two points as a transformation interval, wherein one point is positioned before the threshold point position and the other one is positioned after the threshold point position, performing chirp-z transformation on M points, performing peak value searching on the data after chirp-z transformation, outputting a peak value point position, calculating a difference frequency and a phase according to the peak value point, outputting an object distance, relative radial speed and an azimuth according to the difference frequency and the phase output distance. The invention enables the system to respond fast through processing and optimizing the signal, is good in practicability and faster.
Owner:DALIAN ROILAND SCI & TECH CO LTD
A Method for Extracting the Envelope Parameters of Grid Voltage Flicker
ActiveCN104714075BSimple calculationReduce high frequency errorsCurrent/voltage measurementA wave amplitudeFrequency spectrum
The invention discloses a method for extracting power grid voltage flicker envelope parameters. According to the method, power grid voltage flicker waveforms are sampled at a constant sampling frequency, a flicker envelope amplitude modulated wave component is obtained through energy calculation of an improved Teager energy operator, a cosine window is added to conduct Chirp-Z conversion, the flicker envelope amplitude modulated wave frequency and a correction factor of an amplitude modulated wave amplitude value are extracted by improving the Chirp-Z conversion, and the flicker envelope amplitude modulated wave amplitude value is corrected through the correction factor and accurately obtained; through the combination of the improvement on the energy operator and the improvement on the Chirp-Z conversion, the energy operator is improved, the flicker envelope demodulation calculation process by the energy operator is improved, the noise resistance is improved; by improving the Chirp-Z conversion, the flicker frequency analysis range is flexible and adjustable, and frequency spectrum leakage generated under the condition of asynchronous sampling and errors caused by a picket fence effect are effectively avoided; the correction factor of the amplitude modulated wave amplitude value reduces the errors caused by the energy operator, and the power grid voltage flicker envelope parameters can be accurately measured in real time.
Owner:HUNAN UNIV
Timing synchronization and phase/frequency correction of QPSK signals
InactiveCN1180591CWireless network protocolsSynchronisation signal speed/phase controlFrequency spectrumComputer science
A method and apparatus for digitally demodulating QPSK signals includes a first portion in which the digitally sampled data burst is resampled with a plurality of predetermined timing hypotheses. The timing offset is determined according to an analysis of the resampled data. The digitally sampled data burst is then resampled according to the timing estimation. Modulation of the resampled data burst is then removed by twice squaring the complex I / Q pairs. The data with the modulation removed is then subjected to a Chirp-Z Transform to move the data into the frequency domain. The highest spectral power is used to determine the frequency offset. The phase offset is determined and the resampled data burst is derotated and dephased according to the phase offset and the frequency offset.
Owner:TECH INC
High-precision real-time microwave speed measurement and distance measurement device based on symmetrical triangular lfmcw radar
ActiveCN103630888BImprove real-time performanceHigh ranging real-time performanceRadio wave reradiation/reflectionMicrowaveRadar
The invention provides a high-precision real-time microwave velocity and distance measuring device based on a symmetrical triangle LFMCW radar. In the signal emission stage, the device generates up and down frequency sweeping LFMCW signals whose scanning periods are short; in the signal reception stage, the device collects a path of I analog echo signals and a path of Q analog echo signals orthogonal with each other in real time in a de-sloping manner, accumulates echo data coherently, divides the data into an up frequency sweeping group and a down frequency sweeping group, calculates the peak frequency values of the power spectra of the two groups, offsets deviations of the peak frequency values caused by Doppler frequency generated by a target velocity, and combines CZT (Chirp Z Transform) to obtain a high-precision target distance; and at the same time, beating echo data obtained in multiple scanning periods is sampled to form a new data sequence, spectrum analysis is implemented, peak frequency point values are estimated, and the target movement velocity is calculated. According to the device, the symmetrical triangle LFMCW radar can be used to simultaneously measure the velocity and distance of a moving object in a highly precise manner.
Owner:INST OF ELECTRONICS CHINESE ACAD OF SCI
A robust wake-up signal detection method for underwater communication nodes
ActiveCN105472719BExtended service lifeHigh frequency resolutionPower managementTransmissionUnderwater wireless sensor networksFrequency interval
The invention discloses a stable underwater communication node awakening signal detection method. The stable underwater communication node awakening signal detection method comprises the following steps of: S1, emitting a dual-frequency or multi-frequency awakening signal; S2, according to a set initial frequency, transform point number and frequency resolution ratio, executing CZT (chirp z transform) on a unit circle on the awakening signal; S3, searching an extreme value of a zoom spectrum of CZT, judging a signal as the awakening signal if an estimated relative frequency interval and relative amplitude relationship between frequency components are kept unchanged, or judging the signal is not the awakening signal; and S4, after the signal is determined as the awakening signal, powering on an integral communication node to enable the node to be transferred into a working state, and when the node completes working, cutting off a power supply to enable the node to be transferred into a sleeping state. According to the stable underwater communication node awakening signal detection method disclosed by the invention, due to the high frequency resolution ratio, multiple groups of frequencies can be adopted for combination to awaken a plurality of nodes of an underwater sensor network without worrying about mutual interference, so that detection false-alarm is greatly reduced and a service life of the underwater wireless sensor network is prolonged.
Owner:HARBIN ENG UNIV
Beidou B1 signal high sensitivity capturing method based on chirp-Z transform
ActiveCN107064968AReduce lossImprove capture sensitivitySatellite radio beaconingBluestein's FFT algorithmEnergy loss
The invention belongs to the field of satellite receiver baseband signal processing and relates to a Beidou B1 signal high sensitivity capturing method based on chirp-Z transform, so as to reduce signal energy loss caused by FFT computing fence effects and improve the receiver sensitivity. By using a Beidou B1 signal capturing result in a parallel correlation + FFT method, a Doppler frequency rough estimation result and a pseudo code phase are obtained; according to the pseudo code phase of the capturing result, the local pseudo code phase is adjusted, chirp-Z transform capturing is carried out on signals near the Doppler frequency, the capturing peak is effectively improved, and the receiver sensitivity is improved. The method is mainly applied to high sensitivity capturing on Beidou No.2 B1 frequency point satellite navigation signals and can also be applied to capturing and processing on other similar signals.
Owner:BEIJING AUTOMATION CONTROL EQUIP INST
Synchronization method of carrier frequency and communication equipment in digital communication system
Owner:ALCATEL LUCENT SHANGHAI BELL CO LTD
Fluorescence service life characterization method for pulse delay estimation
InactiveCN110196218AImproving Spectrum Calculation AccuracyImprove relative errorBiological particle analysisIndividual particle analysisFrequency spectrumFluorescence
Provided in the invention is a fluorescence service life characterization method for pulse delay estimation. The method includes the following steps: step one, measuring a time-domain continuous forward dispersion light pulse signal and a time-domain continuous fluorescence pulse signal that are obtained by cell irradiation by laser in a flow cytometry; step two, calculating refined frequency spectrums for time-domain continuous pulse signals by using improved chirp Z-transform, carrying out equal-angle sampling along a spiral curve, calculating limited time width Z transform, and converting the time domain signals into frequency domains to obtain discrete frequency-domain signals; step three, carrying out multiplying on the obtained frequency domains and carrying out zero filling, improving the resolutions of cross-correlation peaks by using a correlation peak interpolation algorithm, and minimizing a peak point interval to obtain a time domain cross-correlation function; and step four, calculating two signal delays based on the time domain cross-correlation function to characterize the fluorescence service life.
Owner:BEIJING INFORMATION SCI & TECH UNIV
A Method of Measuring Radar Cross Section of Moving Target Based on FPGA
InactiveCN108169727BSimple structureClear structureWave based measurement systemsHardware structureScattering cross-section
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA
Rapid sea wave simulation method based on Chirp Z transform
InactiveCN102141612BReduce computationReduced simulation timeWave based measurement systemsSpecial data processing applicationsFrequency spectrumSea waves
Owner:BEIJING INSTITUTE OF TECHNOLOGYGY
Method and system for real-time spectrum analysis of non-stationary signals
A method is provided for performing real-time spectral analysis of a non-stationary signal. The method includes sampling the non-stationary signal, using an observation window having a length short enough to approximate a stationary signal, to provide an initial set of sampled data, buffering the initial set of sampled data to obtain multiple buffered sets of sampled data, filtering the initial set of sampled data and the buffered sets of sampled data, using corresponding filter responses, to obtain multiple filtered sets of sampled data, and performing a chirp-z-transform (CZT) of the filtered sets of sampled data to provide a set of discrete Fourier transforms (DFT) coefficients. A total signal spectrum of the non-stationary signal is reconstructed using the set of DFT coefficients.
Owner:KEYSIGHT TECH
A wavelength label information analysis device and analysis method
ActiveCN102611520BOvercome inaccuraciesMultiplex system selection arrangementsWavelength-division multiplex systemsInformation analysisFrequency spectrum
The invention discloses a wavelength tag information analysis device and an analysis method. The received sampling signals are subjected to chirp-Z transform (CZT) analysis continuously by J times by a logic processing unit, and the frequency-related information of the continuous J times of each wavelength tag frequency in the sampling signals is counted to resolve wavelength tag information, wherein J is an integer larger than zero. Based on the characteristic of CZT that can select an arbitrary start frequency and frequency resolution (or stop frequency), the device and method provided by the invention can realize spectral zooming during frequency analysis by subjecting the sample signal to Z transform, thereby obtaining higher start frequency resolution, and reducing frequency measurement error caused by picket fence effect.
Owner:ZTE CORP
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