Tuning-fork vibratory gyro and sensor system using the same

A sensor system comprising:

• a vibratory gyro;
• a driving circuit for driving the vibratory gyro;
• and
• a detector circuit for detecting an output signal output from the vibratory gyro,
• said vibratory gyro comprising:
• a tuning-fork vibrator having first and second arms, detection electrodes provided only on the first arm, driving electrodes provided only on the second arm, a piezoelectric member, and a ground electrode provided in the second arm such that the driving electrodes are in a floating state with respect to the ground electrode;
• and
• a supporting member supporting the tuning-fork vibrator,
• said tuning-fork vibrator including a base portion integrally formed with the first and second arms,
• said tuning-fork vibrator having a driving-side vibration mode and a detection-side vibration mode different from said driving side vibration mode,
• said tuning-fork vibrator resonating in the driving-side vibration mode, and both said tuning-fork vibrator and said supporting member resonating together as a unit in the detectionside vibration mode, and
• at least one of the first and second arms satisfying a predetermined dimensional condition such that the driving-side vibration mode has a Q value which is constant in a stable frequency range.