| 摘要 |
PURPOSE:To set a self-running frequency without adjustment and to make the range of control broad and stable, by providing a differential amplifier forming a positive feedback loop via a piezoelectric tuning fork element and giving an exciting input to the piezoelectric tuning fork element. CONSTITUTION:The differential amplifier 40 has a positive feedback loop 44 which feeds back positively the output of the differential amplifier to the input via the piezoelectric tuning fork element 42. That is, the amplifier 40 is constituted as a feedback amplifier giving the exciting input to the element 42. A frequency control circuit 46 controls the self-running frequency of the amplifier 40 based on a DC control input given externally. A capacitor 66 is a capacitive element setting the control range of frequency. In the actual oscillating operation, the oscillated frequency is controlled continuously in response to the change in phase. |
