Clock regeneration apparatus for synchronous data transmission
US6144675A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 2, 1998 |
| Grant date | Nov 7, 2000 |
| Priority date | — |
| Expiry date | Jul 2, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J2203/006
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A clock regeneration apparatus which regenerates and distributes a timing signal in a synchronous data transmission network. The network is organized by a plurality of transmission units being linked in a ring topology, and at least two transmission units have external clock sources for synchronization purposes. The clock regeneration apparatus, disposed in each transmission unit, has a clock source list that contains entries for at least two line clock sources provided from neighboring transmission units. A clock selection controller selects a reference clock source with which the transmission unit is to be synchronized. A clock quality transmitter supplies one of the two neighboring transmission units that is not selected as the reference clock source by the clock source selection controller, with a message requesting not to use a corresponding line clock source for synchronization. This message transmission occurs only when the transmission unit is configured as a slave unit, and when the clock quality messages received from the neighboring transmission units exhibit equal clock quality levels continually for a predetermined period.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.