SIGNAL FREQUENCY MEASUREMENT METHOD Russian patent published in 2013 - IPC G01R23/00 

FIELD: measurement equipment.

SUBSTANCE: signal frequency measurement method involves signal reception with further analogue-to-digital conversion, quick Fourier transformation, transformation of numerical massif in time area to numerical massif in frequency area, determination of j_max number of numerical massif element, which corresponds to maximum signal amplitude in frequency area, determines approximate value of the quantity of signal periods at observation interval, creation of 2k+1 reference signals in time area, which correspond as to the shape to initial massif in time area, the quantity of periods of which are offset in relation to the quantity of initial signal periods by j_max *(s/k-1)*b, where s=0,1,2, …2k, where coefficient b determines the neighbourhood size, b=0…1 near approximate quantity of signal periods j_max at observation interval, calculation of correlation coefficients 2k+1 of reference signals with initial one, approximation of ratio of correlation coefficients 2k+1 of reference signals and initial signal from number m in frequency area KK[m], where m=j_max+j_max*(s/k-1)*b, oversampling based on the determined approximating dependence with increase in the quantity of massif elements by R times, i.e. formation of massif KK1[m₁], where m₁=j_max+j_max*(s₁/(k*R)-1)*b, s₁=0,1,…2k*R, R - oversampling coefficient of more than 1, determination of element m_1max of numerical massif, which corresponds to maximum value of correlation coefficient KK1. Value m_1max is accepted as a specified value of the quantity of reference signal periods instead of j_max. Then, all the previous signal processing operations are repeated, thus decreasing each time the value b that determines the neighbourhood size near the determined quantity of signal periods at observation interval. After the required approximation accuracy of evaluation of reflected signal centre position is achieved, frequency value f=m_1max/(N*dt) is calculated.

EFFECT: higher measurement accuracy.

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