Method and apparatus for synchronizing clocks coupled to network
US5848028A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 24, 1997 |
| Grant date | Dec 8, 1998 |
| Priority date | — |
| Expiry date | Nov 24, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J3/0641
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Many devices (in particular white goods or brown goods) in a household may contain a clock. Some systems allow connection of such devices and their related clocks to a common bus or network. The commands for controlling the clocks are in general limited to reading or writing a given time or to broadcasting the time of a given clock to one dedicated device or to the entire system or to a part of the system. In such known systems it is not specified in which manner a clock should react if it receives the time broadcast by another clock. It is possible to initialize all clocks to a given time, but due to tolerances in the different clocks, so achieved synchronization will not be maintained. Regular broadcasting by a special device master clock has the disadvantage of introducing one device with different capabilities. In case there are several master clocks, conflicts may occur and the advantages of a high precision clock will fade away if a lower precision master clock overrides it. In the present invention, only the clock with the highest precision broadcasts its time to the system, but whenever it fails the next lower precision clock takes over the broadcasting automatically. The b…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.