METHOD AND SYSTEM FOR DETECTING PHASE DIFFERENCE BETWEEN INPUT SIGNAL AND OUTPUT SIGNAL OF SYSTEM, AND METHOD AND SYSTEM FOR CONTROLLING PHASE DIFFERENCE

摘要

PROBLEM TO BE SOLVED: To easily and highly accurately detect or control a phase difference between input and output signals of a system even when the output signal of the system is a digital signal having large discrete degree. ;SOLUTION: In these methods, the phase difference between a periodical input signal F(t) inputted to the system and a periodical output signal E(t) from the system which is expressed by discrete data sampled by a prescribed sampling rate is detected or controlled. A detecting variable delay part 36 introduces delay quantity Δtd into an input signal and generates a delay signal for detection. A phase difference deriving part 38 collects a set of two-dimensional (2D) data having the value of the detecting delay signal and the value of the discrete data as elements, optimizes the delay quantity so that the data point distribution of the data set on 2-D orthogonal coordinates becomes approximately straight distribution and finds out a phase angle corresponding to the optimized delay quantity to detect a phase difference Δθ. A controlling variable delay part 34 introduces controlling delay quantity Δtc corresponding to a difference between the detected phase difference and a target phase difference to the input signal to control the phase difference.;COPYRIGHT: (C)2000,JPO