FIELD: physics.
SUBSTANCE: invention relates to spectral analysis and can be used in communication devices and in measurement equipment. Method of spectral analysis of multifrequency periodic signals using the combination of compensation components is that the original signal a(ti), specified by counts of instantaneous values at specified moments of time for sequence of frequencies ω1, ω2, ..., ωi, ..., ωn, (reference frequencies) instantaneous spectral density (ISD) is determined. To achieve technical result, each result of signal and interference conversion, which are formed after multiplying of input signal by sine and cosine of reference frequencies, is divided into two identical components. Obtained signals are processed equally in the respective lines – each of the obtained signals is branched into two identical components. First component is filtered with a low-pass filter (LPF), the band of which is matched with the signal band. Simultaneously, the second component is filtered by a band-pass filter, the pass band of which is selected so that the upper frequency of the band-pass filter corresponds to the upper frequency of the analyzed signal, the lower frequency of the band-pass filter is set equal to a certain predetermined value. Signals passed LPF and band-pass filter are subtracted from each other. Values corresponding to sine and cosine components of one frequency are used to determine instantaneous spectral density (ISD) for each reference frequency proportional to signal amplitude. Obtained values of ISD are compared with threshold, according to results of comparison conclusion is made on presence or absence of signal with corresponding frequency. Phase values are determined using the coherent accumulation method.
EFFECT: high efficiency of spectral analysis in conditions of presence of interference due to compensation of conversion noise.
1 cl, 2 dwg, 1 tbl
