Radio-controlled timepiece

摘要

A radio-controlled timepiece includes an oscillator circuit of which an oscillation condition can be varied by an oscillation condition adjustment circuit that adjusts an oscillation frequency, a frequency divider circuit that divides the oscillation frequency and generates a time measurement reference timing signal, a frequency adjustment circuit that adjusts the period of time measurement reference timing signal, a local oscillator circuit that uses the oscillation frequency as a reference frequency and outputs a local oscillation frequency, and a control circuit. The control circuit, when the radio-controlled timepiece is performing reception operations, causes the oscillation condition adjustment circuit to operate whereby the oscillation frequency is adjust to an optimal frequency for the local oscillator circuit and the variation setting value of the frequency adjustment circuit is set such that time measurement reference timing signal has a fixed period for normal operations and for reception operations.

主权项

1. A radio-controlled timepiece comprising:
a timepiece measuring circuit configured to serve as a reference signal source during a time measurement; a heterodyne receiver circuit configured to receive radio waves from an external source; a PLL circuit configured to generate a local oscillation frequency used by the heterodyne receiver circuit, wherein the timepiece measuring circuit serves as a reference frequency generating unit that generates a reference frequency of the PLL circuit; a control unit that changes an oscillation condition of the timepiece measuring circuit, based on a reception and a non-reception of the radio waves from the external source, the control unit changing the oscillation condition of the timepiece measuring circuit such that the oscillation frequency of the timepiece measuring circuit differs based on the reception and the non-reception of the radio waves from the external source; and a correcting unit that corrects a time measurement drift of a time measurement during the reception of the radio waves from the external source that is relative to a time measurement during the non-reception of the radio waves from the external source, the time measurement drift being consequent to the oscillation frequency of the timepiece measuring circuit differing based on the reception and the non-reception of the radio waves from the external source.