Digital subscriber line modem utilizing echo cancellation to reduce near-end cross-talk noise

US6263077A · kind A · utility

Assignee

• Conexant Systems, LLC · US

Inventors

• Edward S. Zuranski · Largo, US
• Kenneth D. Ko · Clearwater, US
• Jamal Haque · Tampa, US
• Shrenik P. Patravali · St. Petersburg, US
• Manuel I. Rodriguez · St. Petersburg, US
• Keith A. Souders · Tampa, US
• Anthony A. Tzouris · Clearwater, US

Key dates

• Filing date: Feb 23, 1998
• Grant date: Jul 17, 2001
• Expiry date: Feb 23, 2018

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02D30/50
• WIPO field: Digital communication
• WIPO sector: Electrical engineering

Abstract

A digital subscriber line communication system does not require the use of a plain old telephone service (POTS) splitter in the resident's home. Digital signal-processing techniques are utilized to accommodate varying subscriber line conditions coming from POTS telephone equipment. The digital signal-processing techniques eliminate the need for a splitter by reducing susceptibility to distortion resulting from varying subscriber line characteristics. The digital subscriber line modem can utilize quadrature amplitude modulated (QAM) signals and frequency division multiplexing. The digital subscriber line modem includes a control circuit that implements an echo canceler and an analyzer to reduce near-end cross-talk noise. The analyzer performs spectral analysis to preemphasize or to predistort the transmitted signals in accordance with the cross-talk noise.