Adaptive equalizer
US4477914A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 1, 1982 |
| Grant date | Oct 16, 1984 |
| Priority date | — |
| Expiry date | Feb 1, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/03025
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
In a digital system, especially where PCM coded speech is conveyed over twisted pair cables optimized for analogue speech, a pulse is received distorted, the distortion being especially bad on the trailing edge of the pulse. This decays slowly enough to cause intersymbol interference with the next pulse. This is overcome by applying the signal from an amplifier (11), FIG. 4, to one input of a subtractor (12) via a delay and attenuation circuit (13-15) and to the other input of the subtractor directly. The delay (13) is such as to optimize the peak of the received pulse, and the attentuation level is calculated to cancel out the tail of the received pulse so that it is zero at the center of the sampling point of the next bit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.