| 摘要 |
PURPOSE:To perform specific relay transmission by providing an detecting means for a pilot signal for automatic gain contro, a peak rectifying circuit and a mean value adjusting circuit, and a control signal output means, and adjusting the transmission level of the pilot signal for automatic gain control with an automatic gain control signal from the control signal output means. CONSTITUTION:A CATV signal is applied to an input terminal 1 and the pilot signal for AGC is extracted by a band-pass filter 3 from the CATV signal which is distributed partially by a distributor 2, amplified by an amplifier 4, and then detected by a video detector 5. Its video detection output is applied to the peak rectifying circuit 6 and means value rectifying circuit 7. Known constitution is employed for the peak rectifying circuit 6 and mean value rectifying circuit 7. A peak rectification output signal and a mean value rectification output signal are applied from the peak rectifying circuit 6 and mean value rectifying circuit 7 to a comparing circuit 8 and an AGC signal is applied from a select output circuit 9 to an automatic gain control AGC circuit 10 on the basis of the comparison processing result. |
