| 摘要 |
PROBLEM TO BE SOLVED: To follow the change in the resonance frequency associated with the change in the temperature of outside air and in the weight of works mounted on a piezoelectric oscillation apparatus and to follow the best resonance frequency constantly by leaving in a phase-synchronous state even before actuation and correcting the frequency only for phase deference at actuation. SOLUTION: The power source of a piezoelectric oscillation apparatus 11 is turned on, the oscillation frequency of a voltage controlling oscillator 6 is phase synchronized previously by the mobile frequency of a subvoltage controlling oscillator 3, in this state, mechanical oscillation from an oscillation sensor 12 attached to the apparatus 11 is converted into an electric signal, which is sent to a preamplifier 1 to be amplified, and phases of the frequency of the signal from the sensor 12 and of the oscillation frequency from the oscillator 3 are compared by a subphase comparing device 2. As the results of the phase comparison, the frequency is corrected only for the generated phase difference by the oscillator 3 to phase-synchronize with the signal from the sensor 12. |
