| 摘要 |
PROBLEM TO BE SOLVED: To change a frequency with a simple configuration by connecting a switch to the capacitor of an antenna resonance circuit with a plurality of capacitors and antennas in series or in parallel, and by changing the capacitor. SOLUTION: An antenna resonance circuit 10 being used for a radio control clock such as a radio control watch has an antenna 12 and two capacitors 14 and 16 being connected in series. The capacitor 16 is connected to a switch 18 in parallel, and is changed to a circuit or is short-circuited by the switch 18. When interference or a noise signal occurs, the antenna resonance circuit 10 changes a resonance frequency for changing tuning, thus setting the resonance frequency of the antenna resonance circuit 10 within the range of the remote selection of a receiver 20, or arbitrarily performing change between two resonance frequencies. The antenna resonance circuit 10 is connected to the receiver 20. |
