Joint decision feedback equalization and carrier recovery adaptation in data transmission systems
US3974449A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 21, 1975 |
| Grant date | Aug 10, 1976 |
| Priority date | — |
| Expiry date | Mar 21, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/01
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An adaptive feedforward transversal equalizer acting jointly with a data decision-directed demodulating carrier recovery system to achieve substantially jitter-free passband equalization of a suppressed-carrier coherent data signal without the use of pilot tones is improved by adding a feedback transversal filter section operating on past demodulated data symbols. The weighted output of the feedback section is subtracted from the demodulated output output of the feedforward section to provide signals from which data decisions are made and common error signals are derived. Tap-gain coefficients for both feedforward and feedback filter sections and phase angle for the demodulating carrier recovery system are adaptively updated in accordance with the common error signal. Severe frequency offset and phase jitter are simultaneously compensated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.