| 摘要 |
PURPOSE:To give an AGC at a level in which the SN ratio of a tuner and the interference are in the best condition, by controlling the amplifying factor of the tuner through the detection of a signal of an interrupting channel and rejecting the carrier of the reception channel. CONSTITUTION:A tuner 2 is provided with an AGC loop 8 to exclude the interference of an interference channel such as adjacent channels in addition of a conventional AGC loop 6. This AGC loop 8 consists of a means 9 excluding a carrier of a desired channel from the output terminal of the tuner 2 and detecting the signal in an interference channel, an AGC detection circuit obtaining an AGC voltage from the detection level outputted from this detection means 9, and an AGC amplifying circuit 11 amplifying and forming the AGC voltage from the detected output of the AGC detection circuit 10. |
