Modem equalizer training using previously stored parameters
US4621366A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 22, 1984 |
| Grant date | Nov 4, 1986 |
| Priority date | — |
| Expiry date | Feb 22, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/38
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A high-speed modem which acquires receiver operating parameters and equalizer coefficients, stores the parameters and coefficients after an initial modem communication having an initial training sequence, and reinitializes the modem equalizer and receiver at the beginning of subsequent modem transmissions with the previously stored coefficients and parameters to be followed by a shortened training sequence. The modem according to the present invention acquires the above-mentioned parameters and coefficients with improved accuracy by extending the initial training period before the transmission of data. The particular stored receiver parameters include carrier frequency offset and data timing frequency offset parameters. According to the present invention, an additional .DELTA. parameter is determined and stored which optimizes the receiver timing according to a difference between parameters acquired at different portions of the initial training sequence. During subsequent modem transmissions and after restoration of several of the previously used equalizer coefficients and receiver parameters, the modem further acquires the remaining receiver parameters during a very brief training…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.