| 摘要 |
PURPOSE:To compensate a temperature change and a load change to generate always a fixed-amplitude sine wave by feeding back the signal voltage, which is obtained by comparing and amplifying the rectified smooth voltage of the oscillated output and a constant voltage, to the oscillator. CONSTITUTION:In wien bridge type sine wave oscillator 1 using operational amplifier 8, rectifier smoothing circuit 10 where the output of oscillator 1 is inputted through voltage follower 9 is provided to apply the DC output from circuit 10 to input terminal b of differential amplifier 11. Then, the constant voltage obtained by making power source voltages -V and +V into the constant voltage by a Zener diode is applied to input terminal C of amplifier 11 through voltage follower 12, and is compared with the DC output of circuit 10. Then, the output obtained by comparing the constant voltage and the DC output of circuit 10 in amplifier 11 is fed back to the input side of oscillator 1 through FET 18, thereby holding the amplitude of oscillator 1 fixed. |
