Short sample dense frequency signal parameter measurement method

Abstract

The invention discloses a short sample dense frequency signal parameter measurement method, which comprises the following steps of: sampling an input analogue signal x(t) at an equal interval with sampling frequency fs to obtain 2N-1 discrete samples x(n); performing all-phase discrete Fourier transform (apFFT) on the x(n) to obtain a complex sequence Xa(k), obtaining amplitude spectrum by using the modulus of the Xa(k), and finding a spectral peak position k=k0; extracting a frequency range omega of [(k0-1)Deltaomega, (k0+2)Deltaomega] taking k0Deltaomega as a center, performing all-phase discrete Fourier transform (DTFT) on x(n) on the frequency range, and taking the phase spectrum of the transform, wherein Deltaomega is equal to 2phi / N; observing the characteristics of a phase spectrumcurve, and determining single-frequency condition if the phase spectrum curve presents straight distribution characteristics; if the phase spectrum curve presents continuous oscillation, determining dual-frequency distribution condition, and further estimating frequency, amplitude and phase values of two dense components; in addition, determining the multi-frequency conditions of component numbers more than or equal to 3. The method has the characteristic of accuracy controllability.

Description

technical field [0001] The invention relates to a parameter measurement of a frequency signal. In particular, it relates to a method for measuring parameters of short-sample dense frequency signals for digitally measuring frequency, initial phase and amplitude of sine wave signals containing dense adjacent components when short samples are collected. Background technique [0002] The parameter measurement of frequency, amplitude and initial phase of multi-frequency sine wave is a problem often encountered in the engineering field. At present, the digital measurement method of sinusoidal signal has become a widely used measurement method due to its advantages of high precision, flexible scheme and no need to introduce complex circuits. The digital measurement method needs to sample the signal at a certain sampling rate, and then use the digital signal processing algorithm to analyze and calculate the sampled data to obtain the estimated value of frequency, amplitude and init...

AI Technical Summary

Problems solved by technology

However, in engineering practice, there are often not enough samples: for example, in the military, time is life, and there are extremely high requirements for speed and accuracy in the process of data processing, so it is difficult to ensure sufficient time to collect Sufficient samples are used for parameter estimation; another example is that in today’s clinical medicine, it is increasingly necessary to consider the patient’s tolerance time limit, and the excitation signal usually cannot last too long, so usually not enough long enough useful response data can be collected, so clinical diagnosis Analysis must also start with a small number of unique samples

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