Apparatus and method for noise reduction in a digital line receiver
US4864590A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 1988 |
| Grant date | Sep 5, 1989 |
| Priority date | — |
| Expiry date | Jun 30, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/03146
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Apparatus for suppressing intersymbol interference and improving the signal-to-noise ratio in a digital line amplifier includes a filter with a fixed transfer function that couples equalized digital signals to a first differential input of a difference amplifier and substantially filters out high frequency random noise present in the signals to achieve signal-to-noise enhancement with consequent degradation of the signals by intersymbol interference. Subsequently, an output from the amplifier is sampled by a quantizer that produces a bit stream output of portions of the enhanced signals, excluding the intersymbol interference. Signals from the bit stream are then coupled to a fixed coefficient decision feedback equalizer having the same transfer function as the filter and are output therefrom as feedback signals to a second differential input of the amplifier such that the signals at both differential inputs are substantially equal in terms of intersymbol interference, thereby suppressing such interference in the amplifier output.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.