Citizen Watch Company, Ltd.

Shinichi Watanabe

Makoto Yoshida

Fuminori Suzuki

An electronic timepiece is provided with a timebase signal source comprising a relatively low frequency quartz crystal oscillator circuit and with means for compensating the timebase signal frequency for the effects of temperature changes on the low frequency oscillator circuit, and further with means for comparing the timebase signal frequency with the frequency of a relatively high frequency quartz crystal oscillator circuit having high stability against aging changes, to thereby compensate for changes in the timebase frequency caused by aging of the low frequency quartz crystal vibrator, this comparison being carried out only within a specific narrow range of operating temperatures.

Electronic timepiece

A timekeeping signal source for an electronic timepiece produces a highly accurate timekeeping signal which is stable in frequency with respect to both temperature variations and long-term drift. The timekeeping signal is produced by phase lock control using a high frequency reference signal from a crystal-controlled high-frequency oscillator. Phase lock control can be performed continuously or on an intermittent basis, in order to reduce power consumption. In addition, the timekeeping rate can be adjusted with a resolution within one period of the high frequency reference signal, by variation of a numeric value stored in digital memory means.

Growing community of inventors

Tanashi, Japan

Shinichi Watanabe