Patent ID: 7839725

Claim:
A radio wave timepiece, comprising: timekeeping means for keeping current time in response to a given reference clock, the timekeeping means including an oscillator for producing the given reference clock, and a frequency divider for frequency-dividing the reference clock with first and second frequency division ratios to provide first and second reference signals; a receiving antenna including an antenna for receiving first and second standard radio waves each having an amplitude modulated in terms of time information representing the current time; first switch means adapted to the receiving antenna, for switching the standard radio wave between the first and second standard radio waves, the switched radio wave being used as a carrier wave; second switch means adapted to the time keeping means, for switching between the first and second reference signals; detection means including quadrature detection means for extracting an in-phase component and a quadrature component from the carrier wave and amplitude calculation means for calculating an amplitude of the carrier wave in response to the in-phase component and the quadrature component of the carrier wave; and time correction means for demodulating time information in response to the amplitude of the carrier wave for correcting the current time in the timekeeping means based on the time information demodulated by the time correction means, wherein the quadrature detection means is operative to extract the in-phase component and the quadrature component from the carrier wave in response to the one of the first and second reference signals switched by the second switch means.