Keywords

Digital communications, Amplitude Weighted Quadrature Phase Shift Keying (AWQPSK), Comparison with QPSK and MSK, Bandwidth efficiency (bits/sec/Hz), Intersymbol interference (ISI) simulation, Sidelobe suppression (63 dB) and null-bandwidth energy

Abstract

Quadrature phase shift keying (QPSK) and minimum shift keying (MSK) are the two most used M-ary modulation techniques in Direct-Sequence (DS) Spread Spectrum Communication systems. This thesis introduces a new modulation technique that can compete well with QPSK and MSK in many applications. This new modulation technique, made up of a superposition of one QPSK signal and two amplitude weighted QPSK signals, is called Amplitude Weighted Quadrature Phase Shift Keying (AWQPSK). It is found to have the same probability of error as QPSK and MSK techniques. It has a higher bandwidth efficiency in bits/sec/Hz than QPSK and MSK. It has 99.99 percent of its energy within the null bandwidth ·and its sidelobes are 63 db down from the main lobe. Intersymbol interference (ISI) was simulated on an HP 9845 computer and was shown to be smaller than the ISI in a QPSK or an MSK signal. Two different implementation schemes are presented.

Notes

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Graduation Date

1984

Degree

Doctor of Philosophy (Ph.D.)

College

College of Engineering

Degree Program

Electrical Engineering

Format

PDF

Pages

75 pages

Language

English

Rights

Public Domain

Length of Campus-only Access

None

Access Status

Doctoral Dissertation (Open Access)

Identifier

DP0022594

Subjects

Spread spectrum communications; Spread spectrum communications--Mathematical models; Phase shift keying; Digital modulation; Data transmission systems--Computer simulation

Accessibility Status

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