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2 results about "Discrete-time Fourier transform" patented technology
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In mathematics, the discrete-time Fourier transform (DTFT) is a form of Fourier analysis that is applicable to a sequence of values. The DTFT is often used to analyze samples of a continuous function. The term discrete-time refers to the fact that the transform operates on discrete data, often samples whose interval has units of time. From uniformly spaced samples it produces a function of frequency that is a periodic summation of the continuous Fourier transform of the original continuous function. Under certain theoretical conditions, described by the sampling theorem, the original continuous function can be recovered perfectly from the DTFT and thus from the original discrete samples. The DTFT itself is a continuous function of frequency, but discrete samples of it can be readily calculated via the discrete Fourier transform (DFT) (see Sampling the DTFT), which is by far the most common method of modern Fourier analysis.
A power quality monitoring method and apparatus
PendingCN122171877ASpectral/fourier analysisCurrent/voltage measurementPower qualityFrequency spectrum
The application relates to the technical field of power system analysis, and particularly provides a power quality monitoring method and device, which comprises the following steps: sampling power quality parameters by using a three-cycle sampling method; adopting a discrete-time Fourier transform method to analyze the amplitude of each frequency point of a sampling signal; and performing aggregate analysis on the power quality parameters based on the amplitude of each frequency point of the sampling signal to obtain an aggregate spectrum diagram corresponding to the power quality parameters. The technical scheme provided by the application can collect and analyze power quality parameters in a power grid in real time, and accurately judge the power quality state.
Owner:CHINA ELECTRIC POWER RESEARCH INSTITUTE CO LTD +2
Calibration method and device of anisotropic linear array radar, radar and storage medium
The application provides a calibration method and device of a special-shaped linear array radar, a radar and a storage medium. The method comprises: performing discrete-time Fourier transform on echo intermediate frequency signals obtained by each antenna channel of the special-shaped linear array radar detecting a metal column, to determine actual phases of the echo intermediate frequency signals; based on the actual phases of the echo intermediate frequency signals received by each antenna channel, searching for actual position coordinates of the metal column in a position search range of the metal column by using an optimization problem; based on the actual position coordinates of the metal column, calculating theoretical phases of the metal column detected by each antenna channel; based on the actual phases and the theoretical phases of the echo intermediate frequency signals, determining channel calibration factors of each antenna channel; and using the channel calibration factors to calibrate target echo intermediate frequency signals received by the corresponding antenna channel. The application can avoid the problem of unfocused images caused by different gains and phases of different antenna channels in the special-shaped linear array radar, and improve the radar detection effect.
Owner:WHST CO LTD