Time-of-day clock having a temperature compensated low power frequency source
US4448543A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 17, 1983 |
| Grant date | May 15, 1984 |
| Priority date | — |
| Expiry date | Jan 17, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG04F5/06
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An electronic time-of-day clock having a low-power time source and compensation circuits selectively operable responsive to pulses output from the low-power time source when system primary power is off or disabled, and responsive to a relatively highly accurate time-pulse generator when primary power is enabled. The time-of-day clock compensates continuously in real-time for errors in the output of the low-power time source caused by variations in the ambient temperature of the device; when primary power is enabled, the output of the low-power time source is further compensated by comparing the output thereof with the output of the high-accuracy frequency standard and storing accumulated error.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.