Carrier-recovery loop with stored initialization in a radio receiver
US6072842A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1997 |
| Grant date | Jun 6, 2000 |
| Priority date | — |
| Expiry date | Nov 12, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2027/0069
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A carrier-recovery loop for a receiver in a communication system with features that facilitate initialization of the loop. The carrier-recovery loop is a PLL that uses a feedback signal to keep a recovery oscillator phase-locked to the carrier of a received signal. In the present invention, an initializing value of the feedback signal is stored in a memory and provided to a digitally controlled recovery oscillator (DCO). This initializing value brings the recovered signal to an initial frequency that approximates the carrier frequency. When the receivers starts to acquire a phase-lock with the carrier, the carrier-recovery loop is in a condition close to the desired phase lock. Preparing the DCO in this manner imparts a significant improvement to the carrier-recovery loop. The response time for the loop to acquire a phase lock depends in part on its initial frequency offset from the carrier. In general, reducing this initial offset reduces the loop's acquisition time. By thus anticipating the frequency of the carrier, this carrier-recovery loop can have an improved acquisition time to reach phase lock. The initializing value of the feedback signal can be generated by recording a sa…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.