| 摘要 |
PURPOSE:To prevent disturbance due to manual designation from generating, by switching the oscillation frequency of an RF converter by the control signal of a microcomputer. CONSTITUTION:A video signal is separated to only a synchronizing signal at a synchronizing signal separation circuit 4, and is sent to a microcomputer 5. The microcomputer 5 sends information to switch the channel of an oscillator in the RF converter to an RF converter 1 by detecting the presence/absence of the synchronizing signal sent from the synchronizing signal separation circuit 4. However, the circuit is operated only at the setting time of a channel, and after completion of the setting of the channel, the microcomputer continues to send only a bit of channel information to the RF converter 1. In such a way, since mis-designation due to a manual operation is prevented from occurring, and it is possible to eliminate the generation of the disturbance, and in addition, the channel change-over switch of the RF converter can be eliminated, and a device constituted inexpensively can be obtained.
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