Index decoder for digital modems
US4646325A · kind A · utility
7Cited by
5References
3Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 15, 1985 |
| Grant date | Feb 24, 1987 |
| Priority date | — |
| Expiry date | Apr 15, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/38
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
In a QAM digital modem decoder section, the received signals (after equalization) are transposed to a preselected quadrant of the signal constellation to generate an index pointer. The index pointer and the actual quadrant are used to decode the QAM signals. The index pointer is also used to update the equalizer taps and to operate a phase tracking loop used to reduce or eliminate phase jitter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.