| 摘要 |
PROBLEM TO BE SOLVED: To automatically measure in a high accuracy the phase difference component of sign wave signal with a simple device constitution, by processing a detected waveform and a reference waveform respectively, obtaining a real part analysis signal and imaginary part analysis signal mutually forming a Hilbert conversion pair and calculating the phase difference component corresponding to the reference waveform based on them. SOLUTION: With A/D converters 11 and 12, a reference waveform data x(n) and a detected waveform data y(n) (where n is a variable indicating the address of data) are sampled with constant time intervals from the analog value of voltage, current, etc., and stored in waveform memories 13 and 14, and with each Hilbert converter 15 and 16, the discrete Hilbert conversion pair of the data x(n) and y(n). The first operator 1 calculates the phase difference z(n) between the detected waveform y(n) and the reference waveform x(n) based on these 4 analysis signals. The second operator 18 calculates an average value of proper interval excluding the disturbance part of the both ends of a data interval among the phase difference z(n) and outputs as a phase differenceϕ0 .
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