| 摘要 |
PROBLEM TO BE SOLVED: To prevent the disturbance to a digital demodulating section in an electronic device, in which an on-vehicle car navigation set and a television receiver is integrally provided by reducing the higher harmonics of locally oscillated signals. SOLUTION: A serial resonance circuit 34 composed of a capacitor 32 and an inductance 33 is connected to one side of a tank circuit 31, and the resonant frequency of the resonance circuit 34 is matched to the secondary higher harmonic of an oscillation frequency when a specific channel is received. Therefore, the secondary higher harmonic can be reduced, and accordingly, a digital demodulating section 24 can operate stably without receiving unwanted signals from an electronic tuner 21, because the second higher harmonic becomes incapable of being returned.
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