Intersymbol interference cancellation with reduced complexity
US5774505A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 4, 1996 |
| Grant date | Jun 30, 1998 |
| Priority date | — |
| Expiry date | Apr 4, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/03834
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A signal processing channel and method for reducing intersymbol interference in a sequence of data symbols includes a pre-shaping filter for sharpening leading edges of data symbols and providing trailing edges that approximate a decaying exponential. The output of the pre-shaping filter is combined with a cancellation output from a resistance-capacitance circuit having a time constant selected to provide pulse responses that complement the exponentially decaying trailing edges. The combination of the shaped output and the cancellation output is input to a slicer or other decision device. The 2-level output from the slicer is an input to a decision feedback filter that generates the cancellation output. In addition to the resistance-capacitance circuit, the decision feedback filter includes a delay to properly time the coincidence of the cancellation output with the shaped output from the pre-shaping filter. Preferably, the signal processing channel and method include a gain circuit for setting the peaks of the shaped signals and include adaptive adjustment of the gain, the sharpening by the pre-shaping filter, and the RC time constant of the decision feedback filter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.