Adaptive convergent decision feedback equalizer
US5157690A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 30, 1990 |
| Grant date | Oct 20, 1992 |
| Priority date | — |
| Expiry date | Oct 30, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2025/03585
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An adaptive convergent decision feedback equalizer apparatus and method is disclosed for reducing intersymbol interference (ISI) in a data communication system. ISI is cancelled by generating and subtracting an estimation of the interference from a received signal. the estimation is generated by a N-tap transversal filter in which individual delayed received signals stored in the taps are multiplied by the respective adaptable tap coefficient and summed to form a digital representation of the ISI present. The present invention takes two steps to reduce the probability of coefficient adaptation from diverging. First, the DFE performs a coefficient modification only when the delayed received signal is a particular filter tap is a maximum or minimum level of the selected line code. A second step to eliminate divergence addresses the start up coefficient determination and errors in ISI estimation as the filter coefficients grow in size. On start up, only the first P number of DFE taps are chosen for modification and the remaining taps are held at zero. P is a number of taps for which the sum of the uncancelled ISI and the voltage error of an incorrect ISI estimation yields less than 0.…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.