| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a receiving circuit which can demodulate a received standard time and frequency signal appropriately, a radio controlled timepiece, and a control method of receiving circuit. <P>SOLUTION: The receiving circuit comprises a receiving means 3 for receiving either one of a plurality of standard time and frequency signals and demodulating it and a control means for outputting a control signal. The receiving means 3 is provided with a signal amplification section 32 for amplifying a reception signal, a signal extraction section 33 for extracting a signal having a predetermined frequency, a rectification section 351 for rectifying the extracted signal, and a demodulation section 37 for demodulating the rectified signal. The signal extraction section 33 comprises a plurality of crystal filters XT provided in accordance with each frequency of the plurality of standard time and frequency signals, a plurality of parallel capacitances CC which are connected to the plurality of crystal filters XT in parallel and are provided in accordance with the plurality of crystal filters XT, and a filter switching section 331 and a parallel capacitance switching section 332 for switching the crystal filters XT and parallel capacitances CC in accordance with the control signal. The control means outputs a control signal providing a switching state in accordance with a standard time and frequency signal to be received. <P>COPYRIGHT: (C)2008,JPO&INPIT |
