Modems, methods, and computer program products for identifying a signaling alphabet in variance with an ideal alphabet due to digital impairments
US6389064B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 8, 1999 |
| Grant date | May 14, 2002 |
| Priority date | — |
| Expiry date | Mar 8, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2025/03694
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Modems, methods, and computer program products identify a signaling alphabet that is in variance with an ideal alphabet due to digital impairments and is used to decode received data symbols. In particular, a set of alphabet thresholds are established that correspond to the data symbols. The data symbols are received in an equalizer, which generates output symbols in response thereto. A collection of data symbols corresponding to a particular alphabet threshold are accumulated and an average value is computed, which is then used to replace the current value for the particular alphabet threshold to which the average value corresponds. Equalizer performance is enhanced as the improved accuracy of the alphabet thresholds results in better error information being fed back for adapting the equalizer filter coefficients.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.