METHOD MEASURING ROOT-MEAN-SQUARE VALUE OF SIGNAL Russian patent published in 1997 - IPC

FIELD: measurement technology, measurement of root-mean-square value of signal on infralow frequencies when fast action and measurement accuracy during processing of signals changing in large dynamic range is required. SUBSTANCE: method is based on isolation of first harmonic and higher harmonics from spectrum of input signal, on determination of their root-mean-square values. In this case frequency of first harmonic of input signal is determined, reference sinusoidal signal with frequency of first harmonic of input signal is formed, first time interval is selected in which input signal does not change its sign, center of first time interval is found, second time interval is selected in which reference sinusoidal signal does not change its sign, center of second time interval is determined, momentary values of input and reference signals are measured correspondingly from centers of first and second time intervals. Modulus of ratio of momentary values of input and reference signals is found, moduli of relations of momentary values of input and reference signals are determined many times for each pair of time moments equally distant from centers of first and second time intervals correspondingly. Averaged value of moduli of relations of measured momentary values of input and reference signal is found. Root-mean-square value of input signal is determined as square root from sum of squares of two values - product of root-mean-square value of reference sinusoidal signal by averaged value of moduli of relations of measured momentary values of input and reference signals and root-mean-square value of product of momentary values of reference sinusoidal signal by square root from difference of squares of calculated values of moduli of relations of momentary values of input and reference signals and averaged value of moduli of measured momentary values of input and reference signals. EFFECT: fast action and accuracy of measurements when processing signals changing in large dynamic range. 2 dwg