12 results about "Discrete frequency domain" patented technology

The invention discloses a two-dimensional wave field reconstruction method, device and terminal based on spatial sparse sampling, and the method comprises the steps: obtaining an original two-dimensional time domain signal corresponding to an original signal, carrying out the compression sampling of the original two-dimensional time domain signal, and determining a two-dimensional discrete time domain signal; fourier transform is carried out on the two-dimensional discrete time domain signal, and a two-dimensional discrete frequency domain signal is determined; solving a two-dimensional wave number signal according to the two-dimensional discrete frequency domain signal based on a compressed sensing theory; and performing inverse Fourier transform on the two-dimensional wave number signal, determining a reconstructed two-dimensional time domain signal, and determining a reconstructed signal corresponding to the original signal according to the reconstructed two-dimensional time domain signal. According to the invention, the two-dimensional wave number signal is reconstructed according to the two-dimensional discrete frequency domain signal obtained by sampling through compressed sensing, and the reconstructed signal corresponding to the original signal is obtained according to the two-dimensional wave number signal, so that the problem that the two-dimensional wave field data is sampled by adopting Nyquist in the prior art can be effectively solved; the data redundancy is high; and the transmission pressure is large.

A method for deriving a measure of PPG variability which is indicative of fluid responsiveness. The PPG signal is processed with an adaptive re-sampling algorithm which re-samples the signal with a sampling density which is a function of instantaneous pulse rate. When the PPG signal is subsequently transformed with a discrete frequency-domain transform such as an FFT, the resulting frequency spectrum reflects a variability of the sample in which the FM contribution is largely eliminated. This provides variability information which is more reflective of the AM contribution which is the dominant contribution associated with respiration.

The invention discloses a harmonic electric energy analysis method and device and a medium. The invention relates to the field of power grids and solves the problem of low harmonic metering precision. A voltage time domain signal sequence and a current time domain signal sequence are respectively collected for an extra-high voltage direct current system, a four-item five-order Nuttall window function is adopted to carry out weighting processing on time domain signals, and frequency domain energy diffusion caused by signal truncation mutation is avoided through the window function; three adjacent spectral lines with the maximum screening amplitude and interpolation algorithm correction are added after FFT transformation, spectral line information corresponding to the real frequency of harmonic waves is accurately positioned through targeted screening and correction of discrete frequency domain spectral lines, spectral lines of voltage and current signals are independently corrected, and therefore the real frequency of the harmonic waves is obtained. The amplitude and the phase parameter required by the subsequent power calculation are ensured to be true values; and finally, power is calculated based on the corrected voltage and current real amplitude and phase of each harmonic, and total harmonic electric energy is obtained through accumulation, so that the harmonic metering precision is improved, and the accuracy of the total harmonic electric energy is ensured.

This invention provides a multipath TOA calculation method, system, and electronic device based on a ground-based navigation system. The method includes: acquiring the signal spectrum of the ground-based navigation system transmitted through multiple propagation paths in the frequency domain channel, and constructing a discrete frequency domain channel impulse response model related to the signal spectrum; determining the number of propagation paths of the ground-based navigation system signal based on the signal spectrum; and alternately correcting the arrival time and path amplitude of all propagation paths by gradually increasing the number of propagation paths to a second objective function until the first objective function converges, thereby obtaining the target arrival time and target path amplitude for each propagation path of the ground-based navigation system. This invention improves the accuracy of propagation path number calculation, reduces the probability of false alarms and missed detections in complex multipath channels, and improves the accuracy of propagation path arrival time and path amplitude calculation, thereby improving the positioning accuracy of the entire ground-based navigation system.

The invention belongs to the technical field of complex mountain area surface modeling and static correction in seismic exploration, particularly relates to a complex mountain viscoelastic wave field continuation static correction method based on small reflection data, and aims at solving the problem that the imaging quality of seismic data is low due to the fact that a static correction method based on the ray theory is large in error. The method comprises the following steps: acquiring seismic data in a small reflection mode; obtaining a scattered field at the detection point, and solving the parameter disturbance quantity in combination with the corresponding relationship between the parameter disturbance quantity and the scattered field; based on the parameter disturbance quantity, obtaining a quality factor Q of the underground medium and a frequency-dependent phase velocity v through the discretized frequency domain wave equation; updating Q and v until a set convergence condition is reached; and carrying out continuation static correction processing in combination with the updated Q and the updated v to obtain statically corrected seismic data. Static correction is carried out based on viscoelastic waves, and the imaging quality of seismic data is improved.

The present disclosure relates to the field of communication technology, and in particular to an information sending method and device, a communication device and a storage medium. The information sending method comprises: receiving indication information sent by a network device, wherein the indication information is used to determine at least one carrier corresponding to a cell, and the at least one carrier corresponds to at least one discrete frequency domain resource. According to the present disclosure, a terminal can determine at least one carrier corresponding to a cell and at least one discrete frequency domain resource corresponding to the at least one carrier according to the indication information, so that the terminal can perform subsequent operations on the at least one discrete frequency domain resource corresponding to the carrier in the carrier corresponding to the cell.

The invention provides an anti-interference broadband beam forming method based on an analog-to-digital hybrid array architecture, which comprises the following steps of: dividing an array antenna into M sub-arrays with the same antenna number, and independently connecting different sub-arrays with a radio frequency link and an analog-to-digital converter; each antenna in each sub-array is connected with a phase shifter, the phase shifters adopt the same analog beam forming weighted vector to carry out analog beam forming, and M paths of baseband signals are output after down-conversion of a radio frequency link; performing digital sampling and K-point discrete Fourier transform on each path of baseband signal to obtain M paths of discrete frequency domain sequences; determining a beam forming weighting coefficient corresponding to each frequency point of the M paths of discrete frequency domain sequences, performing weighted combination on each path of discrete frequency domain sequences, and outputting one path of discrete frequency domain sequence; and performing inverse discrete Fourier transform to obtain a discrete time domain sequence. According to the low-complexity broadband beam forming method based on two-stage combination of the analog domain and the digital domain, a large-scale antenna system can form a high-gain space directional narrow beam under the broadband condition.

The invention relates to the technical field of cable fault positioning, in particular to a cable fault positioning method and device for a smart power grid. The method comprises the following steps: acquiring a current signal of a cable line, performing wavelet transform to obtain a discrete frequency domain signal, calculating a transient abnormal score of the discrete frequency domain signal at each time point under each scale, and acquiring an initial dynamic threshold value; the initial dynamic threshold value is in negative correlation with the transient abnormal score and is in positive correlation with the reference threshold value; taking a product of a pre-obtained linear threshold scaling coefficient and the initial dynamic threshold as a final dynamic threshold; the linear threshold scaling coefficient is in negative correlation with a structure fusion parameter and a linear structure fluctuation parameter of the current signal; processing the wavelet detail coefficient based on a final dynamic threshold value to obtain a corrected wavelet detail coefficient, and reconstructing a signal to locate a fault position; the problem of positioning failure or misjudgment of fault positioning under a low signal-to-noise ratio is solved.

The invention discloses a fluctuating wind field simulation method and system based on a frequency-dependent uniform discrete strategy. The method comprises the following steps: establishing a target auto-power spectral density function according to actual wind speed time-history distribution characteristics; giving an initial wavenumber cut-off upper limit, and uniformly dispersing a frequency domain and a wavenumber domain at the same time; calculating the relative error of the estimated value of the auto-power spectral density function at each frequency discrete point, if the relative error is greater than a preset error tolerance upper limit, adjusting a wave number cut-off upper limit, and uniformly discretizing the wave number domain again until an error condition is met; according to the adjusted wavenumber cut-off upper limit, redivision of the initial uniform discrete frequency interval is realized; and generating a wind speed time history of the random fluctuating wind field. According to the method, the uniform discrete frequency domain is further divided by adaptively adjusting the wave number interval and controlling the relative error of the power spectrum density function, so that the rapid attenuation of the frequency-wave number spectrum in the wave number domain can be effectively captured, the simulation accuracy is ensured, the number of required wave number discrete points is greatly reduced, and the efficiency is improved.

The invention discloses a deep learning-based master-slave manipulator torque feedback stability control method and system. The method comprises the following steps of 1, generating a master-slave torque feedback original time sequence data set; step 2, re-sampling a unified timestamp, and executing unified coordinate system conversion, dimension normalization and sliding window mode segmentation to obtain a master-slave alignment time sequence state tensor; 3, discrete frequency domain transformation is executed, and feature dimension splicing is carried out to form a master-slave moment frequency-time fusion feature tensor; 4, performing interaction torque evolution through an improved FEDform model to obtain a predicted interaction torque evolution sequence; and 5, according to the predicted interaction torque evolution sequence, calculating a torque change slope sequence, a torque fluctuation peak sequence and a frequency band energy distribution sequence, and forming a torque stability control parameter set. According to the invention, through the improved FEDformer model and moment evolution prediction, stable feedback control of the master and slave manipulators is realized.

This invention provides a frequency domain channel equalization method and system based on ALS (Alternating Frequency Optimization), relating to the field of digital signal processing. The ALS-based frequency domain channel equalization method includes: acquiring a broadband signal as a reference signal, wherein the broadband signal is a linearly modulated (LFM) signal; using a broadband signal generated by a channel mismatch model as the signal to be calibrated; dividing the discrete frequency domain responses of the reference signal and the signal to be calibrated to obtain the discrete frequency response of the desired equalizer; fixing the filter order to obtain the discrete frequency response of the actual equalizer; subtracting the discrete frequency response of the desired equalizer from the discrete frequency response of the actual equalizer to obtain an error expression; solving for the optimal weight vector using the least squares method based on the error expression, and obtaining the optimal solution by direct inversion. Regularization techniques are used to handle the ill-conditioned nature of the matrix, and then multiple iterations are used to calculate the weight coefficients, thereby improving the accuracy of the equalizer.

The invention relates to the technical field of medical image processing and intelligent detection, and discloses an enteroscope image ambiguity detection method based on image recognition. The method comprises the following steps: acquiring multiple frames of enteroscopy images with zero-base pixel indexes at fixed time intervals, averaging three channels of colors, normalizing, and linearly stretching and normalizing gray levels; establishing a two-dimensional discrete frequency domain coordinate for each frame and performing discrete Fourier transform; screening out a high-frequency set through an equivalent centering index and a high-frequency radius threshold value based on one fourth of the diagonal length of the image; calculating high-frequency energy, full-frequency energy and proportions thereof; solving a ratio mean value and a standard deviation in a statistical window, and completing clear and fuzzy judgment by a self-adaptive threshold value; establishing two types of frame indexes; obtaining an amplitude spectrum of the fuzzy frame, performing linear stretching, and generating a pseudo-color heat map; and outputting judgment and performing structured archiving.