| 摘要 |
PURPOSE:To obtain an AGC circuit in which overflow, etc. are not generated, by controlling a gain basing on a reciprocal of a peak value of an input signal, in a negative-modulated facsimile signal. CONSTITUTION:An input signal is inputted to a multiplier 3 and a peak detector 1. The peak detector 1 detects digitally a peak value of the input signal, and inputs it to a reciprocal calculating circuit 2. In this case, a reciprocal of the peak value is given to the multiplier 3, multiplied by the input signal, and a gain is controlled. A weighting coefficient is multiplied to an output of the multiplier 3 by a multiplier 4, and outputted. Accordingly, in case of a negative-modulated facsimile signal, it does not occur that the gain becomes high during a white section having no carrier, and the output overflows when black comes in the next time. |
