| 摘要 |
PURPOSE:To ensure a constant output amplitude at all times against various fluctuations such as element fluctuation of an amplifier circuit, temperature fluctuation and power supply voltage fluctuation by providing a peak detection circuit and a control circuit to the amplifier circuit so as to apply feedback control. CONSTITUTION:A peak detection circuit 12 detects a peak value of an output signal and generates a peak detection signal and the signal is inputted to a control circuit 13. The control circuit 13 compares the signal with a reference voltage and generates a control voltage, and its control voltage is fed to a base of a transistor(TR) 3 forming a current source of a common emitter circuit for TRs 1,2 for an amplifier circuit 11. Thus, the feedback control is implemented to make the output amplitude of the amplifier circuit 11 constant at all times. Thus, the output amplitude is kept constant at all times even against various fluctuations such as element fluctuation of an amplifier circuit, temperature fluctuation and power supply voltage fluctuation. |
