| 摘要 |
PURPOSE:To suppress an envelope variation by inputting a regenerating signal to an amplifier of a low band emphasis type, deriving a peak hold potential of positive and negative from an output of the amplifier, and feeding back an average voltage of the peak hold potential to an input of the amplifier. CONSTITUTION:A signal from a regenerating head 1 is inputted to an inversion amplifier 10 having a voltage gain of a low band emphasis type through an integration circuit 2 and a low band cut-off filter 3. In this case, as for an envelope variation of the regenerating signal, a peak value of a high potential is detected by a diode D1 in a positive peak holding circuit 6, and held by a time constant of a resistance R1 and a capacity C1. It is executed in the same way in a negative peak holding circuit 7, as well. The positive and the negative peak values are added by an adding circuit 8, and an average voltage Vs being the added value is brought to a negative feedback to an input terminal C of the amplifier 10. Accordingly, in the terminal C, the voltage Vs being an inverse voltage against the envelope variation of the regenerating signal is added, therefore, the envelope variation of an output of the amplifier 10 is eliminated. |
