DISTORTION FACTOR SIGNAL MEASURING TECHNIQUE Russian patent published in 1997 - IPC

FIELD: measurement technology. SUBSTANCE: first harmonic and higher-order harmonics are separated from input signal spectrum, RMS value of input signal first harmonic and that of higher order harmonics starting from second one are determined, input-signal first harmonic frequency is measured, sine-wave reference signal is shaped at input-signal first harmonic frequency, first time space is chosen in which signal does not change its polarity, center of first time space is found, second time space is chosen in which sine-wave reference signal does not change its polarity, center of second time space is found, instant value of input and reference signals are measured, respectively, at time moments t₁ and t₂ and t₁ and t₂ which are chosen to be equally spaced, respectively, from center of first and second time spaces, module of instant-input-to-reference signal ratio is determined, modules of instant-input-to-reference-signal ratio are repeatedly determined for each pair of time spaces equally spaced from centers of first and second time spaces, respectively, averaged value of modules of measured instant-input-to-reference-signal ratio are calculated; input signal distortion factor is determined as ratio of RMS values of product of sine-wave reference signal instant values t^ square root of square difference of two values: calculated values of modules of instant-input-to-reference-signal ratio and averaged modules of measured instant-input and reference signal ratios and averaged modules of measured instant input and reference signals as function of product of averaged modules of measured instant input-to-reference-signal ratios by RMS value of sine-wave reference signal. EFFECT: improved measurement accuracy and speed. 2 dwg