METHOD OF MEASURING PHASE DIFFERENCE OF HARMONIC SIGNALS AT OUTPUTS OF LINEAR PATHS WITH LOW SIGNAL-TO-NOISE RATIOS Russian patent published in 2019 - IPC G01R25/00 

FIELD: measurement technology.

SUBSTANCE: invention relates to the metrology. Method for measuring phase difference comprises generating a harmonic measurement signal, in transmitting said signal through analyzed paths, in estimation of signal frequency, in determination and setting of heterodyne signal frequency, in transfer of output signals of analyzed paths to intermediate frequency, obtaining harmonic signals, in measurement of phase difference of signals of intermediate frequency, in determination of phase difference of harmonic signals at outputs of analyzed paths, in display of value of phase difference and frequency of measuring signal. At that value of intermediate conversion frequency is chosen considerably less than values of frequencies of final set of measuring signals, procedure of "optimum heterodyning of signals" is performed, determining and memorizing the value of the frequency of the measurement signal transmitted through the analyzed channels and the heterodyne frequency, sequence of harmonic signals of intermediate frequency and signals of local reference generator of procedure "quadrature phase synchronization of signals" and "quadrature measurement of phase difference of signals" is performed, as well as frequency conversion channels are calibrated. For this purpose, harmonic signal is generated, supplied to inputs of both frequency conversion channels, performing "quadrature phase-out of signals", measured phase difference of signals at outputs of frequency conversion channels is accepted as calibration correction, subtracted from previously measured phase difference and obtained unknown phase difference of output signals of analyzed paths.

EFFECT: high accuracy of measuring phase difference of output signals of analyzed paths.

4 cl, 4 dwg