SU462145A1 - Method for measuring phase shift of a harmonic signal - Google Patents

Description

overlapping pulses in time.

FIG. Figure 2 shows a variant of the flowchart for implementing the method.

The block diagram contains the generator I reference pulse sequence, divider 2, shaper 3 reference sinusoidal stress, resolver 4, shaper 5 selector pulse, shaper 6 pulse fixation, counter 7 and delay line 8.

In this scheme, the phase shift varies between two sinusoidal voltages — a reference one (Fig. 1, 0) and a delayed (Fig. I, d). The reference sinusoidal voltage is formed from the pulse voltage (Fig. 1, b). The impulse voltage is obtained from a reference pulse pattern of the type Lgeander (Fig. 1, a) by dividing the frequency. The reference sinusoidal voltage is synchronized with the reference pulse sequence. At the moment when the delayed sinusoidal voltage passes through a zero value with a positive derivative (Fig. I, d), a fixation pulse of a calibrated duration is produced (Fig. 1, e). equal to the period of the pulses of the reference sequence. Thereafter, the number of the period of the reference pulse voltage is determined, with which the leading edge and the fixation pulse coincide. The starting point is the moment of transition through the zero value of the reference sinusoidal voltage. Then a selector pulse is formed (Fig. 1, e). the temporary position and duration of which correspond to the period of the reference impulse voltage, the previous period, from which the leading edge of the fixation pulse coincides. A sequential delay of the selector pulse generates a pulse sequence of overlapping pulses in time (Fig. 1, e-p). The length of this sequence is

two periods of the reference pulse pattern. The mutual shift of the impulse sequence determines the accuracy of the measurement.

Thus, because of the temporal pattern, and consequently of the phase shift, the fixation impulse coincides with the overlapping sequence pulses. In this case, the goal is achieved, since the maximum measurement error of the value of the time interval is equal to half the time shift between the two sequences.

PRED. M et inventions

A method for measuring the phase shift of a harmonic signal based on measuring in the continuous interval between the transition times the reference and delayed voltages

through zero values, characterized in that, in order to increase the accuracy of phase shift measurement, the moment of transition through the zero value of the delayed harmonic voltage by fixation pulse is recorded

calibrated duration, then divide the entire area of the possible temporary position of the specified pulse into sections of duration equal to the duration of the fixation pulse, determine the area number relative to the moment of transition of the reference voltage through a zero value that coincides in time with the leading edge and fixation pulse, then form a selector impulse whose duration and temporal position

correspond to the area before the coincidence area, then a sequential delay of the selector imiuls forms and a sequence of overlapping pulses in time and, fixing the coincidence of each pulse of the sequence with the fixation pulse, determine the value of the time interval, corresponding to its phase

SHIFT.