| 摘要 |
PURPOSE:To maintain the oscillation period of an oscillation system stably with high precision by feeding the output electric signal of a detection system back to a pulse generating circuit and controlling the generation period of a pulse train outputted from the pulse generating circuit. CONSTITUTION:The motion state of a reflecting mirror 2 fixed to an oscillator 1 is detected by the motion detection system 9 to obtain an electric signal which has a repetitive period equal to the motion of the reflecting mirror 2 (oscillator 1). The output signal of the motion detection system 9 is amplified 10 and branched to two paths; one is applied to a detecting circuit 11 to detect its envelope, which is compared with the voltage of a reference voltage source 13. The output of the comparison 12 is applied to a pulse width modulating circuit 7, which imposes PWM modulation. The PWM waveform is amplified 8 and then applied to a solenoid coil 4. The other output signal from the motion detection system 9 is waveform-shaped 14 and then applied to the pulse generating circuit 5. Thus, the feedback loop to the pulse generating circuit 5 is formed and the output period of the pulse train outputted from the pulse generating circuit 5 is specified by the period of the input signal from the waveform shaping circuit 14. |
