| 摘要 |
PURPOSE:To unnecessitate the piezo electricity conversion element for the exclusive use for detection by dividing an ultrasonic wave oscillator loaded on the titled head into two electrodes and connecting an excitation circuit to one electrode and a piezo electric output detection circuit to the other. CONSTITUTION:A piezo electricity oscillator 12 bonded on head 1 is divided into two electrodes 12 and 13. One of them, the electrode 12, is connected for use for oscillation to an electric power amplifier 14, and the other electrode 13 is connected to be used for detection to a detected signal amplifier 15. With this constitution, an excitation signal generator 19 generates signal of the excitation frequency of the head 1, and this signal is input to the piezo electricity oscillator 10 through a resistor 22 and amplifiers 18 and 14 to excite the head 1. On the other hand, at this time, the oscillation signals of the head 1 acts on the above mentioned amplifier 18 through the electrode 13 for detection, the amplifier 15, a rectifying circuit 16 and an integration circuit 17 with the result of correcting adequately the oscillation of the piezo electricity oscillator 10 to excite the head 1. |
