Publication Date

1999

Document Type

Dissertation/Thesis

First Advisor

Tahernezhadi, Mansour

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Electrical Engineering

LCSH

Signal processing--Digital techniques; Echo suppression (Telecommunication); Floating-point arithmetic

Abstract

DSP technology has evolved at a tremendous pace in the recent past. Increased clock speeds and processing power due to architectural enhancements have made the implementation of computationally intensive algorithms in real time a reality. Echo cancellation is one such application that has immensely benefited from this phenomenon. The main motivation for this thesis was to develop a floating-point DSP system suitable for acoustic echo cancellation (AEC) in teleconferencing applications. Floatingpoint DSP was chosen as it offers a wider dynamic range for the input signal than its fixed-point counterparts. Conventionally, two input/output (I/O) ports are required in the DSP chip to facilitate echo cancellation. In this project, an AEC system was designed and implemented using a DSP chip with one I/O port only. This was made possible by using the A/D-D/A converters in a ?master-slave? topology. A memory expansion board was designed to accommodate the large memory needs. Issues involved in real-time implementation of echo cancellers are also discussed. In addition to discussing some of the theoretical aspects of echo cancellation algorithms, this thesis also compares the effect of fixed-point and floating-point implementations of adaptive algorithms. The effects of finite precision, quantization and dynamic range on the performance of digital filters are also discussed.

Comments

Includes bibliographical references (pages [86]-88).

Extent

xi, 96 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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