| 摘要 |
PROBLEM TO BE SOLVED: To measure the periodically changing alternating current waveform with high accuracy even when it is disturved. SOLUTION: In a phase-shift detecting method, a standard time interval given by integer times the period is determined, (1) the time from a rise of the mth waveform up to a rise of the nth waveform is regarded as a measured time interval, (2) when the measured time interval exceeds the standard time interval +α, (m) is added by 1, and (3) when the measured time interval does not exceeds the standard time interval -β, (n) is added by 1. Then, (4) the measured time interval is between the standard time interval +αand the standard time interval -β, the measured time interval is regarded as a taken-in, adopted time interval, and (m) and (n) are added respectively by 1 for the procedures (1) to (4) to be repeated. An averaged value of the differences between the standard time interval and the adopted time interval is determined for a fixed time, and the phase-shift of the alternating current is detected by the proportion of the averaged value to one period.
|
