| 摘要 |
PROBLEM TO BE SOLVED: To provide an on-vehicle FM receiver that can be set to a voice-muted state to eliminate the influence of noise for a period, or the like when an RDS is searching an alternate broadcasting station. SOLUTION: A gate control circuit 17 has a comparator 18, a DC voltage source 19, an npn transistor Tr1, and a voice mute signal input terminal P1. When a voice mute signal is inputted to the voice mute signal input terminal P1, the npn transistor Tr1 is turned on and the level of the collector becomes low, which is supplied to a gate circuit 20 as a second gate control signal. A switch 21 of the gate circuit 20 opens when the second gate control signal occurs, thus inputting voltage held by a capacitor C to an operational amplifier 13. The voltage held by the capacitor C corresponds to a reception signal before voice mute signal input, thus keeping the output voltage of the operational amplifier 13 constant for a period when the second gate control signal occurs. COPYRIGHT: (C)2009,JPO&INPIT
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