PHASE DIFFERENCE MEASURING CIRCUIT FOR SYNCHRONOUS SIGNAL

摘要

PURPOSE:To precisely measure a phase difference even when the frequency of a standard signal is fluctuated in a phase difference measuring circuit of synchronous rectifying system for detecting the fluctuation of phase of a signal component synchronized with the standard signal from a measurement signal. CONSTITUTION:A phase difference measuring circuit for synchronous signal is formed with a synchronous rectifying circuit 1; a first smoothing circuit 7 having the output of the synchronous rectifying circuit 1 as an input; a phase transfer circuit 5 capable of optionally changing the phase with a standard signal as an input, the output being connected to the synchronous signal input terminal of the synchronous rectifying circuit; a frequency-voltage converting circuit 12 having the standard signal as an input whose central frequency is set to the standard signal frequency, and a voltage adding circuit 14 having the outputs of the first smoothing circuit 7 and the frequency-voltage converting circuit 12 as inputs and capable of regulating the adding ratio of these outputs. The influence of the phase change by the fluctuation of frequency is canceled.