Date of Award


Document Type

Dissertation - Restricted

Degree Name

Doctor of Philosophy (PhD)


Electrical and Computer Engineering

First Advisor

Russell J. Niederjohn

Second Advisor

James A. Heinen

Third Advisor

Steven E. Reyer

Fourth Advisor

Arthur C. Moeller


The problem of accurate extraction of two features of the speech signal affected by additive white noise is investigated. These feati.res are the fundamental frequency of vocal cord vibration and voiced/unvoiced categorization of speech. The extracted features are used in an adaptive pitch processing method for the enhancement of speech intelligibility in noise. A pattern recognition approach is used for categorization of noisy speech. A value of confidence in categorization is used as a primary parameter for the adaptive pitch processing method.

The pitch extraction technique, the classification technique and the enhancement method have been extensively tested. Toe results obtained are discussed and suggestions for further improvements and research directions are presented.



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