Method and apparatus for improved phase shift keyed (PSK) signal demodulation
US5764707A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 9, 1996 |
| Grant date | Jun 9, 1998 |
| Priority date | — |
| Expiry date | Dec 9, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L7/0337
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An improved method for signal demodulation, based upon the assessment of an error statistic which is independent of the content of the data stream. To determine the appropriate sampling point within a data period, multiple sampling points are utilized to generate a set of alternative decodings of the data stream. Associated with each of these alternative sets is an error statistic which is computed based upon a known characteristic of the transmitted stream. For example, in Differential QPSK, the encoded phase change is known to be a multiple of 90 degrees. The error statistic would be a function of the difference between each sampled phase and the nearest multiple of 90 degrees. This error statistic provides a quantifiable measure of quality and noise margin associated with each sampling point. The decoded stream associated with the error statistic of highest quality is then selected as the proper decoding of the transmitted data stream. This invention is particularly well suited for processing small data packets, such as ATM.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.