Theoretical analysis and comparison of three basic digital data communication systems, namely, amplitude-shift keying (ASK), frequency-shift keying (FSK), and phase-shift keying (PSK), for both binary coded and M-ary coded transmissions are presented in this paper. The analysis is limited to only nonfading received signal in additive Gaussian noise. Both coherent and noncoherent detection schemes are considered. A symbol error-rate or probability of error is used as the performance criterion for comparison purpose. / Master of Science