| 摘要 |
PURPOSE:To constitute a switch circuit whose number of parts is small, by equalizing the stop level of auto-tuning, the lighting level of a tuning indicator, and the muting level of FM stereoscope to constitute the circuit into one system. CONSTITUTION:The high level signal outputted to a make signal output terminal (b) is applied to the base of a transistor TR Q1 to turn on the TR Q1 and a tuning LED 1 is lit. A switch S1 is closed simultaneously to set an auto-stop control terminal (e) of a PLL circuit 2 set to the auto-tuning state and auto- tuning is stopped. If a switch S2 is closed, the FM stereoscopic state is set, and a muting output terminal (f) of the PLL circuit 2 is in the low level and a muting circuit 3 is turned on when the terminal (e) is in the high level. A signal by which the TR Q1 is turned on is inputted, the terminal (e) is set to the low level and the terminal (f) is set to the high level, and the circuit 3 is turned off to output the signal.
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