| 摘要 |
PURPOSE:To enable highly accurate measurement of phase, by performing a double integration of a phase difference between a reference signal and an input signal. CONSTITUTION:Phase differences are compared with a phase comparator 5 between a reference signal S1 with a frequency F0 and an input signal S2 with the same frequency F0. A pulse wave S3 with the width corresponding to the phase difference is inputted into an integrator 7 through an integration path 6 to be integrated by (n) pieces predetermined. The voltage integrated is discharged with a discharge path 8 and discharge time thereof is counted with a time counter 9 from a reference clock N.F0 N times as mush as the frequency of the signal S2. A microcomputer 10 receives the results of counting time from the device 9 to compute a phase difference. This computation employs a method to expand the phase difference by double integration, thereby enabling highly accurate measurement of phase with higher resolutions.
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