| 摘要 |
PROBLEM TO BE SOLVED: To avoid interferrence to an adjacent channel due to noise outputted from a receiver which is unable to receive a broadcast radio wave because the broadcast program is finished. SOLUTION: A synchronization detection section 1 monitors a synchronization component of a video signal S1 sent from a receiver (not shown) and when the synchronization component cannot be detected for a prescribed time or over, it is discriminated that a broadcast radio wave due to the end of a broadcast program is stopped and a noise component is sent from the receiver, and a detection signal D is outputted, A video signal switch 2 and an audio signal switch 4 receiving the detection signal D are open to interrupt the video signal S1 and the audio signal S2 to be received respectively to a video modulation section 3 and an audio modulation section 5. Then an output signal S5 is a non-modulated signal not including the noise component. |
