Constant envelope modulation for splitterless DSL transmission

US6212227A · kind A · utility

Assignee

• Conexant Systems, LLC · US

Inventors

• Kenneth D. Ko · Clearwater, US
• David O. Anderton · Austin, US
• Ismail I. Eldumiati · Irvine, US
• Steven A. Gronemeyer · Cedar Rapids, US
• Don L. Harmer · Anaheim, US
• P. Michael Henderson · Tustin, US
• Joel D. Peshkin · San Juan Capistrano, US
• Raphael Rahamim · Orange, US
• Frederic M. Stubbe · Irvine, US
• John Walley · Ladera Ranch, US
• Kenneth S. Walley · Rancho Santa Margarita, US
• Yongbing Wan · Irvine, US
• Edward S. Zuranski · Largo, US
• Jamal Haque · Tampa, US
• Anthony A. Tzouris · Clearwater, US
• Shrenik P. Patravali · St. Petersburg, US
• Ganning Yang · San Jose, US

Key dates

• Filing date: Dec 2, 1997
• Grant date: Apr 3, 2001
• Expiry date: Dec 2, 2017

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04M11/062
• WIPO field: Telecommunications
• WIPO sector: Electrical engineering

Abstract

A digital subscriber line (DSL) communication system that utilizes the high frequency band of a standard telephone line does not require the use of a plain old telephone service (POTS) splitter in the resident's home, which provided isolation between the POTS frequency band (0 to 4 kHz) and the DSL frequency band. Digital signal processing techniques are utilized to adapt to varying subscriber line conditions due to POTS telephone equipment. The digital signal processing techniques eliminate the need for a splitter by reducing susceptibility to distortion due to varying subscriber line characteristics. The digital subscriber line modem utilizes constant envelope modulated signals and frequency division multiplexing, where the constant envelope modulations lessens the intermodulation distortion products due to DSL signals that are transmitted by the modem and which may result in audible noise at the POTS telephone equipment due to non-linearities of the POTS telephone equipment.