RU94010433A - Method of determination of phase shift of harmonic signals - Google Patents

Abstract

FIELD: instrumentation. SUBSTANCE: method refers to determination of phase shift of two sinusoidal harmonic signals. In agreement with method additional harmonic signal X'(t) is formed without constant component-leading one of investigated signals X(t) in phase by angle π/2/2. Phase shift Fy is measured between formed signal X'(t) and other examined signal Y(t) assumed as reference one. Two momentary values of additional signal X'(t) are measured at time moments t1 and t2 and phase shift Fo between two examined signals is determined by formula Fo= m(Fy-Fx), where Fy= arccoss | [X'(t1)/X'(t2)] | for the case where measured signal X'(t) leads reference signal Y(t) in phase; Fy=-arccos |X'(t1)/X'(t2)| for the case where signal X'(t) lags in phase reference signal Y'(t) behind; m=1 for signals where | Fy| ≅(π/2); m=-1 for signals where (p/2)<|Fy|≅ p. EFFECT: increased accuracy of measurement of phase shifts close to 0 or 180 deg even on infralow frequencies, presence of constant components in both examined signals X(t) and Y(t) being assumed.

Claims (1)

The method is intended for use in measurement technique in determining the phase shift of two harmonic signals. Purpose: improving the accuracy of measurements. The essence of the invention: form an additional harmonic signal X '(t) without a constant component, outstripping in phase by an angle π / 2 one of the studied signals X (t), measure the phase shift Fy between the generated signal X' (t) and the other studied signal Y (t), taken as the reference, measure two instantaneous values of the additional signal X '(t) at time t1 and t2, and the phase shift Fo between the studied signals is determined by the formula: Fo = m (Fy-Fx), where

for the case when the measured signal X '(t) outstrips the reference signal Y (t);

for the case when the signal X '(t) is out of phase with the reference signal Y (t); m = 1 for signals when

m = -1 for signals when

Positive effect: low measurement error of phase shifts close to 0 or 180 ^o even at infralow frequencies, the presence of constant components in both studied signals X (t), Y (t) is allowed.