| 摘要 |
PROBLEM TO BE SOLVED: To reduce the starting time, without raising the max. amplification factor of a variable gain amplifier more than prescribed from the view of the stability, etc., in the case of controlling for saturation of the output voltage waveform of the variable gain amplifier, keeping the noise low, and holding the amplitude of a tuning fork oscillator const. SOLUTION: A switch means 21 for switching the amplification degree of a voltage amplifier 6 provided at a variable gain amplifier 5 or the latter stage thereof is provided to raise the amplification factor by a switch means 21 only when required for starting, and keep the max. amplification factor of the variable gain amplifier 5 at the conventionally prescribed vale after entering at least a final control region. |
