Method and apparatus for acquiring a frequency without a reference clock
US6856206B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 25, 2001 |
| Grant date | Feb 15, 2005 |
| Priority date | — |
| Expiry date | Jun 25, 2021 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S331/02
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A clock and data recovery system acquires a clock embedded in an input data stream by detecting the occurrence of transitions in the input data stream falling into a predetermined phase zone of a sample clock used to sample the input data stream. A control circuit counts how many evaluation intervals have at least one transition in the predetermined phase zone. The control circuit determines if lock is achieved according to the count. If it is determined that lock is not achieved, an output of a variable oscillator circuit used in the clock recovery operation is adjusted until the number of evaluation intervals having one or more transitions in the predetermined phase zone is below a level indicating lock.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.