Clock management method and transmission apparatus for synchronous network system
US6618455B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 16, 1999 |
| Grant date | Sep 9, 2003 |
| Priority date | — |
| Expiry date | Aug 16, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J2203/006
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In a clock management apparatus for a synchronous network system, when the quality of a clock signal is deteriorated, the clock signal is switched to another clock signal automatically to continue synchronous communication. Clock signals are received and extracted by transmission/receiving units of the synchronous network system. A plurality of clock signals including the extracted clock signals and a clock signal from an external clock are selectively switched by a clock switching unit, and a master clock signal is selected and output based on quality information transferred with each clock signal. The master clock signal is applied to a clock generator generate a clock signal. A quality control table is used to convert quality information into associated quality levels. A quality determination processing unit issues an alarm when the quality level of the master clock signal is deteriorated beyond a threshold provided by a synchronization management table.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.