14 results about "Chirp rate" patented technology

The invention relates to the technical field of power equipment state monitoring, and discloses a partial discharge detection method and system based on synchronous compression wavelet-synchronous extrusion. The method comprises the following steps: preprocessing a partial discharge signal; calculating a coefficient through continuous wavelet transform and estimating an instantaneous frequency and a chirp rate; synchronous compression is carried out to compensate the phase, and scale remarking is carried out; energy is reallocated to a frequency axis through synchronous extrusion, and a high-aggregation-degree time-frequency diagram is generated; extracting a peak domain based on the saliency spectrum, demodulating along a ridge line, and estimating event parameters; and finally, robust judgment and auditing output are completed by using the joint statistics. According to the method, the sensitivity and robustness of partial discharge signal detection under the conditions of low signal-to-noise ratio and strong interference are remarkably improved.

This signal parameter estimation device is configured to comprise: a candidate value setting unit (1) that sets a plurality of candidate values for a chirp rate representing the ratio of chirp frequency width to chirp time width of a reception signal, which is an observation signal of a chirp signal that is the target for parameter estimation; and a candidate value selection unit (2) that multiplies the reception signal by opposite-phase components of each of the candidate values set by the candidate value setting unit (1), converts the reception signals after the opposite-phase component multiplication to signals of a frequency region, and selects, from among the plurality of candidate values, the candidate value for which an electrical power peak value of the signal of the frequency region is relatively larger. Moreover, the signal parameter estimation device comprises: a frequency width estimation unit (3) that multiplies the reception signal, which is the observation signal, by the opposite-phase component of the candidate value selected by the candidate value selection unit (2), converts the reception signal after the opposite phase component multiplication to a signal of the frequency region, and, on the basis of frequency intervals included in the post-conversion signal of the frequency region which correspond to a plurality of electrical power peak values, estimates the chirp frequency width; and a time width estimation unit (4) that estimates the chirp time width from the chirp frequency width estimated by the frequency width estimation unit (3) and the candidate value selected by the candidate value selection unit (2).

The FMCW LiDAR system includes an optical drive electronic circuit to receive a reference frequency signal and a beat frequency signal to generate a drive signal. The optical drive electronic circuit includes a TDC to calculate a phase difference between the reference frequency signal and the beat frequency signal and a digital ramp control to: provided the phase difference is a positive value, produce a ramp down control signal to increase a current chirp rate to an increased chirp rate; provided the phase difference is a negative value, produce a ramp up control signal to decrease the current chirp rate to a decreased chirp rate. The optical drive electronic circuit includes a digital integrator to generate a digital output based on at least one of the ramp down control signal or the ramp up control signal and a DAC to convert the digital output to an analog output.

The application discloses a method for estimating the sweep period of linear frequency modulation interference, and is mainly used for estimating the sweep period of linear frequency modulation interference in the field of signal processing and the like. The method can preset a transform order and a calculation parameter, generates a coefficient required for fractional order Fourier transform calculation, and does not need to normalize the dimension of input data in advance. According to different transform orders, fractional order Fourier transform calculation is performed on input data, until the average peak value interval is calculated after multiple peak values appear in the transform domain. Finally, the sweep period is estimated according to the current searched transform order and the average peak value interval. The method greatly reduces the calculation complexity of the sweep period estimation, multiplexes the anti-interference hardware architecture, saves the hardware resources, does not need to normalize the dimension of input data in advance, increases the compatibility of the method, and does not need to search the period with a fixed length, thereby reducing the calculation amount and increasing the estimation accuracy.

The invention discloses a chirp modulation frequency offset and timing joint estimation signal synchronization method and a chirp modulation frequency offset and timing joint estimation signal synchronization system, which relate to wireless communication and signal processing technologies, and comprise the following steps: completing coarse synchronization by using a demodulation result of an upper chirp in a lead code; the method comprises the following steps: accurately estimating frequency offset and time offset of signals based on a forward chirp signal and a reverse chirp signal in a chirp signal pilot frequency sequence synchronization head, intercepting a section of forward sweep frequency signal at the synchronization head, and performing refined spectrum estimation on an upper chirp spectrum peak position of the forward sweep frequency signal; intercepting a section of reverse frequency sweep signal at the synchronization head, and performing refined frequency spectrum estimation on the lower chirp spectrum peak position of the reverse frequency sweep signal; and resolving a peak value generated by a signal frequency spectrum according to refined frequency spectrum estimation results of the forward frequency sweep signal and the reverse frequency sweep signal to obtain a frequency offset compensation result. According to the method, errors generated by the system can be estimated with fewer symbols, and the method is applicable to different chirp rate conditions.

The application discloses a kind of laser detection device and method, belong to laser detection technical field, the device includes beam output module, light splitting module, optical path multiplexing module, two coherent mixing modules and signal processing module;Beam output module outputs the positive and negative double-chirp laser of frequency-modulated time sequence synchronization of different wavelength, chirp rate absolute value equal, after light splitting, optical path multiplexing, get local light and echo light, two coherent mixing modules generate four-way quadrature beat frequency signal, signal processing module does product subtraction and addition operation to four-way beat frequency signal and constructs complex signal, offset Doppler broadening interference introduced by rotating polygon mirror, again Fourier transform, peak searching obtains intermediate frequency parameter and calculates target vector velocity, the application can completely eliminate the influence of Doppler broadening on speed measurement, significantly improve speed measurement precision.

The application provides a real-time correction method and device for detecting equipment operation parameters, equipment and a medium, and belongs to the technical field of ore body exploration. The method comprises the following steps: acquiring point cloud data of a target area based on a detecting equipment; calling a preset dynamic local quality model to perform spatial division and physical property identification processing on the point cloud data to obtain a quality voxel; performing multipole moment expansion and gravity projection processing on the quality voxel to obtain a terrain gravity correction number; performing frequency shift conversion and modulation processing on a frequency shift parameter of a radar scanner based on the terrain gravity correction number to obtain a compensation frequency shift parameter, which is used for adjusting a laser chirp rate to offset a phase shift of the radar scanner; and correcting an operation parameter of a gravimeter in the detecting equipment based on the compensation frequency shift parameter. The above scheme can effectively improve the stability of the detecting equipment in performing an exploration task.

To provide a distance and velocity measurement apparatus that can be adopted preferably in a LiDAR or a sensor for a robot, wherein the apparatus can prevent deterioration of SN ratio even in a case where an object in an external environment vibrates. A LiDAR 20 according to the present embodiment includes a first laser apparatus 1a, a second laser apparatus 1b, a polarization-maintaining type optical fiber 2, a WDM filter 6, an optical fiber coupler 3a, an optical amplifier 11, an input / output unit 4, an optical scanner 5, a second optical fiber coupler 3b, a balanced photodetector 7, and a square-law detector 9. Further, a delay line 10 composed of a polarization-maintaining optical fiber is provided on the local port 2b. The first laser apparatus 1a includes a device for generating a first laser light having a first wavelength and a first chirp rate in an interior thereof, and the second laser apparatus 1b includes a device for generating a second laser light having a second wavelength that differs from the first wavelength and a second chirp rate that differs from the first chirp rate.

The invention relates to a system and a method for simultaneous range and velocity measurement in an FMCW LiDAR system. A first light source produces first light having a first frequency that varies according to a first chirp rate. A second light source produces second light having a second frequency that is constant or that varies according to a second chirp rate. A splitter separates the measuring light into reference light and output light, and a scanning unit directs the output light towards an object and receives input light that is obtained by reflection of the output light at the object. A detector detects a superposition of the reference light and the input light. A computing unit computes unambiguously the range and relative velocity by analyzing beat frequencies resulting from the superposition. Ambiguities due to Doppler frequency shifts are removed by performing a decision tree analysis.

The application relates to the field of biometric identification technology and discloses a multi-modal handwriting dynamic feature extraction and identification system. The system synchronously acquires macro kinematic sequences and micro acoustic emission sequences, performs time axis regularization based on a bottom-layer hardware interrupt signal, extracts instantaneous geometric singular points of the macro kinematic sequences, combines stress checking to intercept effective micro windows, performs phase space line integral calculation in the effective micro windows to extract macro dissipation work parameters, applies phase compensation to the micro acoustic emission sequences based on corresponding physical coordinates to realize beam forming, acquires micro friction frequency response chirp rates, fuses the dissipation work parameters and the chirp rates to generate high-dimensional identification feature vectors, and inputs the high-dimensional identification feature vectors into a classifier to output a judgment result. The application quantizes a real dynamic physical work process of writing, effectively resists high-precision mechanical arm impersonation attacks, overcomes the defects that a single-channel acoustic acquisition is susceptible to bottom noise and dispersion interference, and improves identification stability in a complex environment.

The application discloses a broadband laser pulse chirp rate measuring method and device. The method is as follows: a broadband chirp pulse is divided into two beams, a reflected beam keeps original beam characteristics as a measured light, a transmitted beam becomes narrow pulse width and narrow spectrum light as a probe light after filtering, the two beams are incident in a non-collinear way in a nonlinear crystal to generate sum frequency through space-time coupling, a crystal is optimally adjusted to obtain a maximum intensity sum frequency signal, a spectrometer is used to measure the sum frequency spectrum and record the data; a probe light path is adjusted to change a relative synchronization relationship with the measured light, so that the probe light scans from a front edge to a rear edge of the measured light, and a delay path amount and a corresponding sum frequency spectrum are recorded; and the chirp rate is calculated according to a corresponding relationship between the sum frequency spectrum and the path delay amount. The device for realizing the method comprises a beam splitter, three mirrors, a narrow-band filter, a path delay device, a nonlinear crystal, an electric angle adjusting frame, an absorber group, a lens and a spectrometer.

The invention relates to the technical field of optical detection, and particularly provides a coherent anti-Stokes Raman scattering imaging method and device, and the method comprises the steps: splitting initial light emitted by a driving light source into driving light and Stokes light; processing the driving light into signal light based on an optical parameter amplifier; performing pulse broadening processing on the signal light on a first light path of the signal light, or performing pulse broadening processing on the Stokes light on a second light path of the Stokes light; combining the signal light and the Stokes light to a third light path, and performing pulse broadening processing on the signal light and the Stokes light on the third light path to obtain the signal light and the Stokes light with matched chirp rates; and performing coherent anti-Stokes Raman scattering imaging on the target sample based on the signal light and the Stokes light which are matched with the chirp rate. The problem that the hyperspectral imaging quality and the hyperspectral imaging speed cannot be considered at the same time in the prior art is solved.

The application discloses a wireless mobile communication method based on generalized orthogonal chirp division multiplexing, and relates to the field of wireless mobile communication. The method comprises the following steps: GOCDM modulation, double-selected channel modeling, received signal modeling, GOCDM demodulation under the double-selected channel, and channel equalization. The GOCDM communication system is applicable to a double-selected channel (i.e. a time-varying multipath channel). Each orthogonal base wave of the GOCDM is a Zadoff-Chu (ZC) sequence. The ZC sequence is determined by a sequence length N and a root coefficient l. The waveform of the GOCDM can be regarded as a digital chirp signal. When the N is fixed, the root coefficient l determines the chirp rate, namely the digital frequency modulation rate. The root coefficient l increases the flexibility of system design. By changing the l, the digital frequency modulation rate can be changed. When the l of the GOCDM is 1, the GOCDM is equivalent to a conventional OCDM system. Since the orthogonal base wave of the GOCDM is a digital chirp signal, the GOCDM has the characteristics of time-frequency domain double diffusion. The application improves the reliability of high-speed wireless communication on the double-selected channel.

This invention discloses a method for classifying deep carbonate sedimentary cycles based on matched Chirplet compression transform (MCST). The method includes: inputting the seismic signal to be analyzed; calculating the instantaneous frequency and group delay in the short-time Fourier transform domain to obtain the chirp rate function; deriving the IF band center and constructing the time-frequency energy focusing domain in the chirplet transform domain; accurately obtaining the local rate of change of the instantaneous frequency trajectory in the chirplet transform domain by constructing a matched Chirplet rate estimator; redistributing the time-frequency coefficients to the true instantaneous frequency trajectory in the time-frequency energy focusing domain through compression transform, thereby obtaining the time spectrum of matched chirplet compression transform (MCST); applying this method to perform time-frequency characterization of seismic trace data, and classifying deep carbonate sedimentary cycles by analyzing the changing trends of the tuned frequencies in the time spectrum.