Apparatus and method for clock recovery in a communication system
US5898744A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 7, 1996 |
| Grant date | Apr 27, 1999 |
| Priority date | — |
| Expiry date | Oct 7, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J3/0632
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method for recovering the clock in an ADSL (asymmetric digital subscriber line) communication system at the receiver to match the frequency of the transmitted signal. A digital phase locked loop (DPLL) based clock is used to adjust the frequency of data read accesses from a FIFO (first-in first-out) memory (26) in a transceiver unit. The frequency is adjusted according to a predetermined offset value, where the offset value indicates the relative difference between a read location in the FIFO memory (26) and a write location. The predetermined offset value defines an operating point or nominal data location in the FIFO memory (26). A FIFO phase detector (31) determines and affects the frequency adjustment to maintain the FIFO memory at approximately the operating point. One embodiment provides clock recovery for a received ADSL subchannel and a means to recover a 16 kHz clock for a channel control.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.