| 摘要 |
A radio receiver, especially one for automotive vehicles, includes a selector switch operable to cut off the audio stage unless the r-f stage is tuned to a carrier modulated by a pilot frequency which triggers a detector therefor into emission of an enabling signal. With the selector switch operated, a bistable component - which could be a flip-flop or a pair of cascaded relays with holding contact - generates a disconnect signal until the enabling signal appears, whereupon the audio stage remains connected even upon a fading of the modulated carrier until the arrival of an interrupt signal due to the manipulation of a knob or pushbutton serving to retune the receiver. |
