Digital Subscriber Line Modems

Prof. Brian L. Evans
Department of Electrical and Computer Engineering
The University of Texas at Austin

Monday, November 20th, 5:30 PM, CPE 2.208

bevans@ece.utexas.edu

Abstract

Asymmetric Digital Subscriber Loop (ADSL) technology allows high-speed data access. The downlink data rates vary according to the quality of the line from 1 to 9 Megabits per second. The uplink data rate varies from 384 to 640 kilobits per second.

ADSL is based on discrete-multitone modulation in which multiple digital Quadrature Amplitude Modulation signals are combined via an inverse Fourier transform and transmitted as a single signal over an ADSL line. The inverse Fourier transform implements discrete multitone modulation. This talk will cover the fundamentals of ADSL modems, including multicarrier modulation, cyclic prefix, channel shortening, sample synchronization, and symbol synchronization.

Biography

Brian L. Evans is an Associate Professor in the Department of Electrical and Computer Engineering at The University of Texas at Austin, and the Director of the Embedded Signal Processing Laboratory. His current research focuses on the design and real-time implementation of ADSL/VDSL transceivers, desktop printer pipelines, video codecs, and 3-D sonar imaging systems. His B.S.E.E.C.S. (1987) degree is from the Rose-Hulman Institute of Technology, and his M.S.E.E. (1988) and Ph.D.E.E. (1993) degrees are from the Georgia Institute of Technology. He was a post-doctoral researcher from 1993 to 1996 at UC Berkeley in system-level electronic design automation as part of the Ptolemy project.

A list of Telecommunications and Signal Processing Seminars is available at from the ECE department Web pages under "Seminars". The Web address for the Telecommunications and Signal Processing Seminars is http://signal.ece.utexas.edu/seminars