| 摘要 |
PURPOSE:To obtain an appropriate vibration detecting output from a vibration detecting piezoelectric element by providing a canceling circuit which cancels the voltage of a frequency signal for driving contained in the output of the piezoelectric element. CONSTITUTION:A vibration detecting piezoelectric element (s) is provided on the side from which the B-phase of a B-phase driving piezoelectric element is impressed and an electrode S which fetches the signal of the element (s) is provided on the opposite side. A differential amplifier 11 is provided between a driving electrode B and the electrode S. The waveform of the electrode S is shaped in a sine wave upon which the voltage component applied across the opposite side of the piezoelectric element is superimposed. Namely, a waveform shaped by superimposing a vibration detecting signal and B-phase driving waveform upon another is outputted from the electrode S. Therefore, when the amplifier 11 removes the superimposed waveform component, the sine wave is obtained. When the signal is used as the vibration detecting signal, an oscillatory motor can be driven at the optimum frequency. |
