Date of Award

Summer 1992

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)


Electrical and Computer Engineering

First Advisor

Heinen, James A.


In speech processing one of the important applications is to improve the intelligibility of speech in low signal-to-noise ratios. The approach being pursued at Marquette to accomplish this is performed by enhancing speech with extracted features. These extracted features include the pitch frequency, the noise spectrum, the energy contour, the voice/unvoice decision, and the formant frequencies. For the purpose of improving speech intelligibility the formant frequencies are crucial. It has been shown that an improvement of +9 decibels (dBs) in the speech from which the formant frequencies are extracted results in a substantial improvement in intelligibility in a cepstral based speech enhancement algorithm [1]. This thesis documents an examination of different formant tracking algorithms to achieve a more robust speech signal in low signal-to-noise ratios (SNRs). Quantitative results such as RMS error, missed formants within a frequency range around the correct formant and extraneous formants are considered. The Diagnostic Rhyme Test (DRT) is used to provide qualitative results to determine effects on speech intelligibility.



Restricted Access Item

Having trouble?