Lin Yu

Document Type

Thesis - University Access Only

Award Date

1997

Degree Name

Master of Science (MS)

Department / School

Electrical Engineering

Abstract

Existing National Television System Committee (NTSC) standard will be phased out and replaced with High Definition Television (HDTV) standard within the next 10 years. There are two competing modulation schemes, Quadrature Amplitude Modulation (QAM) and Vestigial Sideband Modulation (VSB), available for HDTV transmission over bandlimiting and nonlinear channels. The cost and performance of the two schemes are remarkably similar. On the other hand, a third transmission system, Pulse Amplitude Modulation (PAM) is proposed, which is much simpler and uses the channels more efficiently. So the performance of QAM, VSB and PAM transmission systems via bandlimiting and nonlinear channels needs to be studied. In this thesis, QAM and PAM systems via bandlimiting and nonlinear channels are simulated using Signal Processing WorkSystem (SPW) (VSB block is not available in SPW currently). The simulation results indicate QAM systems have a better performance (up to 30% less bit-error-rate (BER)) than PAM systems when passing through both the bandlimiting and nonlinear channels. In addition, QAM and PAM systems over Additive White Gaussian Noise (A WGN) channel are simulated in order to verify their theoretical BER vs CNR (Carrierto-Noise Ratio). The calculated and simulation results are in good agreement. Finally, a QAM system over a multipath channel is simulated. The simulation results show that the adaptive equalizer at the receiving end of a QAM system can be used to cancel the distortion in a multipath channel.

Library of Congress Subject Headings

High definition television
Amplitude modulation -- Simulation methods

Format

application/pdf

Number of Pages

65

Publisher

South Dakota State University

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