Clock recovery circuit
US5987085A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 26, 1997 |
| Grant date | Nov 16, 1999 |
| Priority date | — |
| Expiry date | Mar 26, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L7/033
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A phase locked loop, which does not require a local reference clock to obtain a frequency lock. The circuit includes a frequency locked loop and a phase locked loop in which the frequency locked loop does not require a local reference clock. The frequency locked loop includes a transition counter having an input for data with an output connected to a charge pump. This charge pump is connected to a loop filter, which in turn is connected to a voltage controlled oscillator. The output of the voltage controlled oscillator is connected to a second input in the transition counter. The phase locked loop includes a phase detector with an input for data. The output of this phase detector is connected to a second charge pump, which has it output connected to the loop filter. The output of the voltage controlled oscillator also is connected to the input of the phase detector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.