METHOD OF SPECTRAL ANALYSIS OF PERIODIC MULTIPLE FREQUENCY SIGNALS, CONTAINING INTERHARMONICS AND GIVEN BY DIGITAL READ-OUTS

摘要

FIELD: instrument making.;SUBSTANCE: present invention pertains to information processing systems and measuring techniques and can be used in determining spectral content of a periodic multiple frequency signal, containing interharmonics and given by digital read-outs. For an initial signal a(t_i), given by readings of instantaneous values for a series of frequencies ω₁, ω₂,…, ω_k,…, ω_n, the instantaneous spectral density is determined. Amplitude Am_k and phase φ'_k of detected frequency components of the signal ω_k, are successively determined. From the obtained values of Am_k, ω_k, φ_k , the spectral content of the initial signal a(t_i), can be determined. Values of instantaneous spectral density S(ω_k) are determined using the first programming unit. Using the third programming unit, values of auxiliary instantaneous spectral density S₀(ω_k) can be determined at the same time as the values of instantaneous spectral density S(ω_k). The given values for the next frequency are determined. The process is repeated until equation of frequencies ω_k and ω_n. Using the second programming unit, the difference S_p(ω_k) between values of instantaneous S(ω_k) and auxiliary instantaneous S₀(ω_k) spectral densities is determined. Using the expression: , where A_my is the preset value of amplitude, from frequency values ω_k, corresponding to extreme values of difference in characteristic of distribution of instantaneous spectral density S_p(ω_k) of the initial signal, extreme values of S_p(ω_k), are detected. The amplitude Am_k of detected frequency components of the initial signal (ω_k) is then determined using the first calculator. The phases φ_k of detected frequency components of the signal (ω_k) are determined using the second calculator. When determining phases of frequency components the following conditions are used: for S₁(ω_k)0 and S₂(ω_k)0, φ_k(ω_k)=φ'_k(ω_k); for S₁(ω_k)0 and S₂(ω_k)0, φ_k(ω_k)=φ'_k(ω_k)+180; for S₁(ω_k)0 and S₂(ω_k)0, φ_k(ω_k)=φ'_k(ω_k)-180; for S₁(ω_k)0 and S₂(ω_k)0, φ_k(ω_k)=φ'_k(ω_k); using the fourth programming unit, values Am_k and φ_k, corresponding to ω_k, are stored. The first and third programming units are set such that, the signal at the inputs of the programming units reach the outputs of the sensor of the analysed signal. The first and second calculators are set such that, the signal at the inputs of the calculators reaches the outputs of the second programming at the same time, and the signal from the output of the calculators and the second programming unit reaches the outputs of the fourth programming unit.;EFFECT: increased selectivity of detecting frequency components of a signal during analysis of the spectral content of a periodic multiple frequency signal, containing interharmonics and given by digital read-outs.;3 dwg, 2 tbl