JPS55152425A - Phase difference measuring device - Google Patents

Abstract

PURPOSE: To measure a phse difference on the basis of signals input into a phase difference measuring device from a plurality of points in a short time, by employing a simple processing circuit for measuring a phase difference between two arbitrary points.

CONSTITUTION: Detected signals from displacement detectors 1, 2 provided in two points among many points on a structure are amplified by amplifiers 3, 4 to be applied to filters 5, 6. Signals x₁, x₂ from for filters 5, 6 are applied to an adder 7 and then to a rectifier 8. Output signals from the rectifier 8 are separated into positive and negative signals, which are applied to integrators 9, 10, respectively, to determine the areas represented thereby. The sum total of the areas is calculated by an adder 11. On the basis of this value, variations in phase difference are determined in a phase difference checking means 12. A measured signal in this method contains a large amount of frequency component, and a superior component has a greater amplitude. Accordingly, when an increase and decrease in an absolute value of the sum of two signals are traced, variations in phase difference can be determined or information as to whether an oscillation mode is being changed or not can be obtained. A phase difference measuring device according to this invention has been achieved on the basis of the above technique.

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