The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 08, 1988
Filed:
Jul. 01, 1985
Hitomi Aizawa, Nagano, JP;
Hiroshi Yabe, Nagano, JP;
Seiko Epson Corporation, Tokyo, JP;
Abstract
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.