Nonlinear equalizer for correcting intersymbol interference in a digital data transmission system
US4468786A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 21, 1982 |
| Grant date | Aug 28, 1984 |
| Priority date | — |
| Expiry date | Sep 21, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/03146
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A non-linear equalizer corrects for intersymbol interference in a digital data transmission system by introducing baud rate samples into an N-stage tapped delay line and provision is made for storing a sequence of M prior decisions in a prior decision register. Both the samples from the tapped delay line and the contents of the prior decision register are coupled to a weighting matrix processor which is updated to permit adaptation to different channels conditions. When initially placed into operation, a training sequence is coupled to a reference register and differences between arrived-at decisions and the true symbols are employed to provide an error vector which is then used to update the weighting matrix in the processor. Decisions on the data estimates are hard-limited to form a set of M prior decisions which are placed into the prior decision register. The training sequence is employed over a suitable acquisition time so that the weights of the processor matrix will have stabilized at values suitable for the channel through which unknown digital data will be transmitted. Because the equalizer of the invention is non-linear, it can remove intersymbol interference without the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.