Tianfang Liu

Publication Date


Document Type


First Advisor

Tahernezhadi, Mansour

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Electrical Engineering


Digital communications--Mathematics; Signal processing--Digital techniques--Mathematics; Wavelets (Mathematics)


Wavelet theory has been well developed over decades, and it has numerous applications. Recently, a new method, known as Wavelet Transform (WT), has been introduced in digital signal processing. This technique combines wavelet theory and multiresolution signal analysis into a single theory. It provides a very general technique in signal processing and therefore has numerous applications. In some applications, we observe pseudo-periodic signals, such as speech or music signals, or periodic signals, such as Evoked Potential (EP) and Eletroencephalogram (EEG) signals in biomedical field, with background noise. The additive noise will degrade the performance of digital signal processor. In this thesis a new class of transform called Multiplexed Wavelet Transform (MWT), based on the ordinary WT, and its application in the enhancement of such signals are introduced. Based on the wavelet decomposition with selected components, the additive noise will be suppressed and noise reduced signals will be obtained. Wavelet Transform also has applications in today’s telecommunications. In the multiple access communication systems, if wavelet sequence is chosen as the signature sequence, information at different subchannels could be transmitted simultaneously without intersymbol interference. In such a multiple access system, the error between ideal channel and practical channel is reconstructed using perfect reconstruction filter banks and used for the adaptive channel equalization. In comparison with conventional channel equalization techniques, it provides implementation possibility and reduced computation cost. The discussion and simulation results are presented in this thesis.


Includes bibliographical references (leaf [81])


viii, 80, [1] pages




Northern Illinois University

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