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US 4,730,286 AGranted
Circuit and method for correcting the rate of an electronic timepiece
AssigneeSeiko Epson Corporation
InventorsHitomi Aizawa, Hiroshi Yabe
Life of this patent
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AssigneeSeiko Epson Corporation
InventorsHitomi Aizawa, Hiroshi Yabe
Estimating the term…
Rate change in a quartz crystal timepiece due, for example, to aging of a capacitance used for correcting the frequency-temperature characteristic of the crystal oscillator of the timepiece, is corrected by dividing the oscillator output signal to provide a minimum rate adjustment unit signal and a rate adjustment timing signal. A rate adjustment step width signal consisting of a number of minumum rate adjustment unit signals is predetermined for all of the timepieces in a production run. The number controls the repeated counting of unit signals to produce a series of step width signals. The rate adjustment required for correct timekeeping is determined as an integral number of step width signals. The latter number is set into a second counter in the timepiece to generate a rate adjustment signal. The rate adjustment signal controls the duty cycle of a switch which adds reactance to the crystal oscillator circuit to effect the rate change.
A circuit for use in correcting the rate of an electronic timepiece, the rate adjustment circuit comprising:
The rate adjustment circuit of 1 in which the means for providing a rate adjustment signal further comprises:
The method of adjusting the rate of an electronic timepiece to compensate for the effects of aging and the like, the timepiece having a quartz crystal oscillator which provides a standard frequency signal for driving the timepiece, a reactive circuit component for changing the frequency of oscillation of the timepiece from the standard frequency to a second frequency, and a switch for coupling the reactive circuit component to the oscillator, the method comprising the steps of:
Dependencies are inferred from the claim text.