11 results about "Spectral leakage" patented technology

The application discloses a window function optimization-based windowed interpolation FFT harmonic analysis method and system, which comprises the following steps: performing equal-interval synchronous sampling on a power grid signal to be measured; constructing a multi-objective optimization model of an M-term cosine combination window, and setting a constraint condition; performing iterative optimization on the constructed multi-objective optimization model to generate a time-domain sequence of a customized optimal window function; performing p-order self-convolution processing on the time-domain sequence of the optimal customized window function to obtain a self-convolution optimization window; performing point-by-point windowing processing on a discrete sampling sequence according to the time-domain sequence of the self-convolution optimization window, performing fast Fourier transform on the windowed sequence to obtain a discrete frequency spectrum of the signal, locating frequency spectrum peaks corresponding to each harmonic / sub-harmonic in the discrete frequency spectrum, extracting four characteristic spectral lines near the peaks, constructing a weighted ratio variable, and solving a frequency offset through a pre-fitted odd polynomial. The application can solve the problem of the fence effect, and improve the spectrum leakage suppression capability and the anti-interference performance.

The application provides a baseband radio frequency signal data feedback processing method based on vector modulation, which first receives a baseband signal data set transmitted by a target radio frequency link in a preset frequency band, which contains multiple signal frame original modulation parameters and corresponding radio frequency feedback signal waveforms, then calculates feedback error indicators composed of phase offset, amplitude distortion and spectral leakage factor according to the radio frequency feedback signal waveforms, quantizes the modulation error, analyzes the feedback signal waveforms in the time-frequency domain, extracts error feature vectors, inputs the pre-trained model for cross-frame correlation learning, generates a dynamic adjustment parameter sequence containing time sequence dependence, and finally constructs a closed-loop feedback control link based on the dynamic adjustment parameter sequence and the original modulation parameters, so as to realize accurate processing and optimized control of the baseband radio frequency signal and effectively improve the signal transmission performance.

This invention relates to the field of exosome quantitative analysis technology, and discloses a multi-parameter joint quantitative analysis method and apparatus for exosomes based on the fluorescence intensity of encoded microspheres. The method includes: performing three-dimensional spatial attitude inversion to obtain a three-dimensional attitude characterization vector and constructing a feature point diffusion function; performing spatial deconvolution processing using the feature point diffusion function, and combining it with a visibility weight calculated from the longitudinal depth deviation for brightness gain compensation to obtain intrinsic feature intensity; constructing a channel intermodulation matrix to perform signal decoupling operations, obtaining decoupling intensity and mapping it to quantified abundance. This invention solves the problems of projection distortion, defocus blurring, and spectral leakage caused by random attitude, eliminates steric hindrance effects and system nonlinear interference, significantly improves the accuracy and repeatability of exosome detection, and achieves accurate analysis of high-fidelity biological quantitative information.

The application discloses a kind of amplitude and phase high-precision estimation method and device suitable for fast dynamic change signal, the method of the application includes the discrete signal sequence of continuous signal sampling, constructs Hankel matrix and decomposes left singular matrix U, diagonal matrix D, right singular matrix V;The estimated value of the number of frequency components p is estimated by D, combined with extracting the subspace of right singular matrix V and using least square method to obtain diagonal matrix Q;The damping coefficient of frequency component is calculated by Q and constructs system matrix A;The dynamic phasor coefficient vector S is calculated by A and discrete signal sequence using least square method;The amplitude and phase of continuous signal are calculated by S and damping coefficient.The application aims at solving the problem that the main lobe overlap of dense harmonic / interharmonic with small frequency interval in power system causes spectral leakage interference, extremely serious even can submerge part of main spectrum line, and then lead to the accuracy of spectral leakage affecting the amplitude and phase estimation of dynamic change signal.

This invention discloses a broadband transmission response measurement method for underwater acoustic transducers based on instantaneous frequency tracking. The method uses a linear frequency modulated (LFM) signal to excite the transducer under test (DUT), simultaneously acquiring the voltage and current signals at the transducer's input, as well as the sound pressure level (SPL) signal received by a standard hydrophone. The time-frequency spectrum is obtained through short-time Fourier transform. A peak search combined with parabolic interpolation instantaneous frequency tracking strategy is employed to accurately extract the instantaneous frequency and corresponding voltage, current, and SPL amplitudes at each moment to calculate the instantaneous transmission voltage and current responses. After outlier removal, smoothing, and logarithmic frequency space interpolation, a continuous and smooth response curve is obtained. This invention effectively overcomes the spectral leakage problem of non-stationary LFM signals, achieving simultaneous measurement of the transmission voltage and current responses. It offers advantages such as high measurement accuracy, complete information, high efficiency, and standardized results, and is suitable for broadband response testing of underwater acoustic transducers.

The application particularly relates to a power signal effective value calculation method and system based on a phase-locked loop and a sliding window. The method comprises the following steps: S01, a discrete sampling of a continuous target electric signal is carried out by an analog-to-digital converter based on a preset fixed sampling frequency; S02, a phase-locked loop module receives the discrete sampling data, carries out phase tracking and frequency estimation, and detects and outputs the running frequency of the target electric signal in real time; S03, a dynamic window length n is calculated based on the fixed sampling frequency and the running frequency of the target electric signal; S04, the first 2n-1 discrete sampling data stored in a cache unit are called, the dynamic window length n is taken as a reference, and point-by-point sliding calculation is carried out with a step of 1 to obtain n intermediate root mean square values; and S05, arithmetic average processing is carried out on the n intermediate root mean square values to obtain the effective value of the target electric power signal. The method can solve the problems of spectrum leakage and excessively large calculation error caused by non-synchronous sampling, and improve the calculation precision of the effective value of the electric signal in a non-synchronous sampling scene.

This invention relates to the field of power system parameter monitoring technology and discloses a high-precision analysis method for electrical parameters based on a lightweight DSP algorithm, comprising the following steps: sampling and data buffering, lightweight DSP core processing, electrical parameter output, and code-level optimization. This invention suppresses spectral leakage through integer-cycle sampling combined with window functions, achieving harmonic measurement accuracy of ±0.5%. After Kalman filtering, data fluctuation is reduced by 80%, and steady-state accuracy is improved to within 0.1%, enabling high-precision measurement. Simultaneously, downsampling and integer operations reduce computational load, and code-level optimization keeps CPU utilization ≤15%, allowing it to run on low-cost MCUs such as the STM32F407.

Signal processing methods based on compressed sensing (CS) theory, intended to solve storage space and communication limitations in a Nyquist sampling framework, have attracted increased attention in recent years. In conventional harmonic detection, sparse bases are typically represented by a discrete Fourier transform (DFT) matrix. Harmonic non-synchronous sampling inevitably leads to spectral leakage and fence effect. To address this issue, we present an improved CS model for harmonic detection in power systems. A windowing technique is introduced in the compression sampling process. The fixed-point continuation algorithm combined with interpolation technique is used to directly extract harmonic parameters from the sparse coefficients without reconstructing the original signal. The proposed harmonic detection method, using an improved CS model, can achieve an accuracy comparable to that of the windowed interpolation FFT algorithm.

This invention discloses a radar target detection method for complex road surfaces, belonging to the field of vehicle-mounted radar technology. The method involves processing the target signal through steps such as intermediate frequency signal sampling, signal FFT operation, spectral leakage suppression, image suppression, and target search. It then filters the original target based on characteristic values ​​such as phase difference and amplitude ratio. This invention enables radar systems to effectively suppress spectral leakage by distinguishing interference signals caused by strong reflectors such as fences, overpasses, and tunnels from the target signal, reducing the number of false targets and the probability of false alarms. This results in higher target detection accuracy, greater reliability, and lower computational load for the radar system, making it applicable to complex road sections such as fences, overpasses, and tunnels.

The application discloses a kind of digital downsampling decimation filter architecture design methods based on frequency band division.The method first determines the target frequency band of input signal and original sampling frequency, and obtains the frequency pre-estimate of signal by the fast frequency estimation mechanism based on hysteresis comparator;Subsequently, according to the estimated frequency, the full frequency band is divided into multiple independent sub-bands, and the downsampling multiple and enable control signal are dynamically matched;Then, the signal is input into the decimation filter architecture of double-path multi-stage cascade, for the low-frequency resolution and spectrum leakage problem of wideband signal under high-speed sampling, the problem that the group delay of traditional multi-stage cascade filter is too large under high-rate decimation is broken, and high-fidelity downsampling and high-precision frequency domain analysis of wideband signal are realized.