Electronic watch
US4155218A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 20, 1977 |
| Grant date | May 22, 1979 |
| Priority date | — |
| Expiry date | Apr 20, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG04G3/022
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In an electronic watch, the content of the memory associated with the adjusting circuit of the division ratio of the frequency divider is modified at each correction of the display to compensate for the frequency error of the crystal oscillator and to thereby reduce the running error of the watch. Such electronic watches use a crystal oscillator whose frequency is not optimum. To compensate for the frequency variations due to manufacturing tolerances, age and temperature, correction circuits are incorporated into such watches. When an operator acts on a switch on the case of the watch to correct the time display indication, the content of the memory is modified to correct for the frequency error of the crystal oscillator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.