| 摘要 |
PURPOSE:To make it possible to simplify operation of radio receivers, by performing on/off control on the power source simultaneously through operation of channel selection switch and by executing the channel selection and power supply control at the same time through the operation of an optional channel selection switch. CONSTITUTION:Electronic channel selection controlling circuit 2 controls the tuning frequency of radio receiver 1 which contains a voltage varactor diode in its tuning circuit. When channel selection switch 3a is closed, the cathode of diode D2a is grounded through switch 3a, and energizes relay L2 and closes normally open contact points (e) and (f) by conducting transistor TR1 in controlling circuit 7. Then, a signal corresponding to swich 3a from circuit 2 is applied to receiver 1. When switch 3a which is under reception and another switch 3b are closed, relay L2 is excited and contact points (e) and (f) are closed. By performing the channel selection and power supply control simultaneously through operation of an optional channel selection switch as mentioned above, the operation of radio receivers can be simplified. |
