Vibration gyro having bias correcting function, and method of using vibration gyro

A vibration gyro comprising:

• drive masses configured to be driven and vibrated;
• a sense mass configured to be displaced by a Coriolis force generated by an angular velocity;
• a drive signal generating part configured to generate a multiplexed drive signal by multiplexing a first drive signal and at least one second drive signal, the first drive signal having a first frequency corresponding to a resonance frequency of the drive masses, and the at least one second drive signal having at least one second frequency different from the first frequency;
• a first demodulation circuit configured to generate a first demodulation signal by demodulating a detection signal of the sense mass at the first frequency;
• at least one second demodulation circuit configured to generate at least one second demodulation signal by demodulating the detection signal of the sense mass at the at least one second frequency;
• a first control circuit configured to generate a first feedback amplitude signal from the first demodulation signal;
• a second control circuit configured to generate a second feedback amplitude signal from the at least one second demodulation signal;
• a feedback signal generating part configured to generate a first multiplexed feedback signal by multiplexing a first feedback signal and at least one second feedback signal, the first feedback signal being obtained by modulating the first feedback amplitude signal at the first frequency, and the at least one second feedback signal being obtained by modulating the second feedback amplitude signal at the at least one second frequency;
• and
• a subtracter configured to output an angular velocity signal by subtracting the second feedback amplitude signal from the first feedback amplitude signal.