| 摘要 |
PROBLEM TO BE SOLVED: To improve spurious radiation from an antenna except for receiving a radio program without deteriorating the sensitivity of receiving the radio program for a device that has a function of radio program reception and a reproduction function of a Compact Disk or the like and uses a headphone cord or the like in common use for the antenna. SOLUTION: In the case of receiving a radio program, no control signal is applied to a control terminal 6 of a spurious radiation prevention circuit 5, a transistor(TR) Q1 is turned off and a received signal induced in a headphone cord 8 is given to an antenna terminal 3 without attenuation. In the case of reproducing a Compact Disc or the like, the control signal is applied to the control terminal 6, the TR Q1 is conductive, and the headphone cord 8 is connected to ground is terms of high frequencies by capacitors C2, C3, C4 so as to prevent a noise signal generated in device from being emitted from the headphone cord 8.
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