Patent ID: 7903501

Claim:
A radio-controlled timepiece that receives a standard time signal containing a time code and adjusts the time based on the received standard time signal, comprising: a reception unit that receives the standard time signal; an analog/digital conversion unit that digitizes the received standard time signal based on a prescribed threshold value; a time counter that keeps time; a time code generator that generates a reference time code based on the time counted by the time counter; a duty evaluation unit that calculates the pulse duty cycle of the digital signal output from the A/D conversion unit, and determines if the received pulse duty cycle that is calculated matches the duty cycle of the reference time code generated by the time code generator; a level changing unit that changes the relative level of the threshold value to the reception signal if the duty evaluation unit determines that the received pulse duty cycle does not match the duty cycle of the reference time code; and a time code decoder that decodes the digital signal and demodulates the time code if the duty evaluation unit determines that the received pulse duty cycle matches the duty cycle of the reference time code.