Patent ID: 7515887

Claim:
A radio-controlled timepiece comprising: an antenna that receives a radio signal including a time code having current time information; a tuning unit that outputs a signal corresponding to the radio signal received by the antenna, the tuning unit having a variable-capacitance unit; an amplifier unit that amplifies a signal output from the tuning unit; a receiving unit that extracts the time code from a signal amplified by the amplifier unit, the receiving unit having a filter unit that selectively allows one of plural frequency signals to pass therethrough, and a detection unit that extracts the time code from a signal having passed through the filter unit to output the time code; a time-correcting unit that acquires current time information from the time code extracted by the receiving unit to correct a current time clocked by a clock unit; a display unit that displays the current time clocked by the clock unit; and a control unit that detects a voltage level of a signal output from the amplifier unit at a plurality of points while changing a capacitance value of the variable-capacitance unit, that uses, as a tuning point, a point meeting a given requirement among the points where the voltage level has been detected, and that sets the capacitance value of the variable-capacitance unit at the tuning point as a capacitance value to receive the time code when it is judged that a time code has been output from the receiving unit at the tuning point; wherein when it is judged that no time code is output from the receiving unit at the tuning point, the control unit controls the filter unit so as to change the frequency that the filter unit allows a signal to pass therethrough.