| 摘要 |
PURPOSE:To always secure an assured muting action when the channel is switched, by providing a nonshort type switch and a short type switch which interlock each other with every switch of the channel. CONSTITUTION:The nonshort type switches X1, X2 and so on interlock the short type switches Y1, Y2 and so on. When switching the channel, the tuning voltage caused by the volume VR2 is applied to the tuner 6 with a delay of a certain time given from a start of operation. At the same time, the pulse voltage is generated at the resistance RO at the moment of start of a switching action. Thus pulse voltage is detected at the detecting circuit 4, and the muting signal generating circuit 3 of the next stage is driven at the rise part of the pulse. In such way, the muting signal is always generated earlier than the change of the tuning voltage. Thus an assured muting action is ensured. |
