Patent ID: 8875577

Claim:
An oscillator circuit comprising: an oscillator that vibrates while being driven by a driving signal, and outputs a monitoring signal according to the vibration; a filter that filters the monitoring signal and outputs the filtered signal; a driver that amplifies the filtered signal to generate the driving signal; and a controller for controlling a passing characteristic of the filter based on the monitoring signal, the controller adjusts a center frequency of a passing frequency band of the filter based on a frequency of the monitoring signal, the oscillator further vibrates with a sensing vibration according to an amount of inertia applied from outside of the oscillator, and the controller adjusts the center frequency of the passing frequency band of the filter so as to cause the center frequency to become: a) lower than the frequency of the monitoring signal when a frequency of the sensing vibration is higher than the frequency of the monitoring signal, and b) higher than the frequency of the monitoring signal when the frequency of the sensing vibration is lower than the frequency of the monitoring signal.