| 摘要 |
PURPOSE:To avoid noise during search, by making 0 the audio output during search with the audio muting circuit and enabling the audio output automatically when the serach is stopped and the reception is made. CONSTITUTION:The synchronizing separation output 11 from the video amplifying and synchronization separation circuit 4 is given to the synchonization identifying circuit 9 to obtain the output 12 which is at high potential when the synchronizing signal can be confirmed and at ground potential when not identified. When this output 12 is fed to the switch circuit 10 and the synchronizing signal is not present, the input to the audio amplifier circuit 7 is interrupted and audio output is produced to the speaker 8 only when the synchronizing signal is present. |
