| 摘要 |
PROBLEM TO BE SOLVED: To provide a phase modulator drive circuit, which allows the phase to be adjustable over a wide range of environmental temperatures and has an automatic phase adjusting function who will not latch up due to noise, etc. SOLUTION: The phase modulator drive circuit for adjusting the phase of a phase modulation signal, so that a desired signal and a reference signal are in phase in synchronous detection for extracting sinΔϕs or cosΔϕs component (Δϕs : phase difference between a clockwise and counterclockwise lights with respect to angular velocity) used for detecting the angular velocity by a light interference angular velocity meter comprises a first and second ramp generators for generating a first sawtooth wave signal, having the same period as a phase modulation frequency and a second sawtooth wave signal phase-shifted by 90 deg., respectively, first and second comparators for comparing the first and second sawtooth wave signals with the magnitude of a phase control signal, respectively, and an SR flip-flop set or reset by output signals of the first and second comparators, thus driving the phase modulator by the output of the flip-flop.
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