Use of modified line encoding and low signal-to-noise ratio based signal processing to extend range of digital data transmission over repeaterless two-wire telephone link
US5809033A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 20, 1995 |
| Grant date | Sep 15, 1998 |
| Priority date | — |
| Expiry date | Nov 20, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q2213/13322
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
The range of digital data communication services, such as a basic rate 2B1Q ISDN channel, to customer premises located beyond the industry standard achievable range of a two-wire loop can be extended by increasing the capacity of the ISDN line code from two information bits per symbol to three information bits per symbol, so as to reduce the effective symbol rate, which is error correction encoded to an effective 4B1H line code for defining a sixteen level PAM signal waveform, and employing enhanced low signal-to-noise ratio signal processing techniques in both the transmitter and receiver to accommodate the increased insertion loss of the two-wire line resulting from its extended length. Such enhanced low signal-to-noise ratio signal processing techniques include a Tomlinson precoder in the transmitter, and an adaptive linear equalizer and a module unit in the receiver.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.