| 摘要 |
PURPOSE:To reduce the effect of the gain fluctuation at an amplifying part, by adding the compensating voltage in accodance with the gain fluctuation of the amplifying part to the output voltage of an automatic gain control loop. CONSTITUTION:The input signal is applied to an amplifier 2 via a variable attenuator 1. The output of the part 2 is turned into an automatic gain control signal via a wave detector 3 and a loop amplifier 4. The compensating voltage A of the gain fluctuation of the part 2 is added to the above-mentioned automatic gain control signal through an adding part 6 to be applied to the attenuator 1. The attenuation factor of the attenuator 1 is controlled by the output of the part 6. Thus a signal of a desired size is obtained at an output terminal. |
