Feedforward nonlinear equalization of modulated data signals
US4213095A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 4, 1978 |
| Grant date | Jul 15, 1980 |
| Priority date | — |
| Expiry date | Aug 4, 1998 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/01
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A feedforward nonlinear signal (P(n)) is added to each sample of a linearly equalized received signal (Q(n)) to provide compensation for nonlinear intersymbol interference. The received signal is a modulated data signal impaired by linear and nonlinear distortion as well as phase jitter and additive noise. The feedforward nonlinear signal added to each sample is comprised of a weighted sum of products of individual ones of the samples and their complex conjugates. Each multiplicand bears a predetermined temporal relationship to the sample currently being processed. In an illustrative embodiment, compensation for second- and third-order intersymbol interference is provided by including two- and three-multiplicand weighted products in the feedforward nonlinear signal. Weighting coefficients for each product are adaptively updated in a decision-directed manner.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.