METHOD OF SPECTRAL ANALYSIS OF POLYHARMONIC SIGNALS AND DEVICE TO THIS END Russian patent published in 2009 - IPC G01R23/16 

FIELD: instrument making.

SUBSTANCE: invention relates to measuring instruments and can be used in discrete analysis of polyharmonic signals, including those that feature fast variations of fundamental frequency. The proposed method consists in that the analyzed signal is fed to the input of ADC with its additional input receiving, simultaneously, an additional signal isolated from the said analysed signal with the help of fundamental frequency isolation unit. The ADC sampling interval is selected to be constant to obtain simultaneously sequences of discrete samples of tested and additional signals. Then, proceeding from the additional signal discrete sampling sequence, the tested signal fundamental frequency cycle is computed along with the number of sampling intervals that more closely corresponds to fundamental frequency cycle value. Then, discrete samples with interval equal to the number of tested signal sampling intervals are selected from the sequence of tested signal discrete samples. Now, the correction factor equal to the ratio of product of the number of tested signal intervals by sampling interval to tested signal fundamental frequency cycle is calculated. Discrete harmonic analysis is made by multiplying arguments of all trigonometrical functions incorporated with the formulae for calculation of cosine and sine factors of Fourier series by aforesaid correction factor. The invention covers also the device for implementation of abode described method.

EFFECT: higher accuracy, possibility to calculate spectral components for every signal cycle.

2 cl, 4 dwg, 2 tbl