A Unified Analysis of 16-QAM

The results of an analysis and computer simulation of 16-ary quadrature amplitude modulation (16-QAM) in the presence of realistic implementation losses are presented. Sources of degradation treated in the model include intersymbol interference due to a range of filter types and bandwidths at both the transmitter and receiver, errors in bit synchronization, phase reference, and AGC level, as well as adjacent channel interference from similarly modulated signals. In particular, a detailed analysis of a system which approaches Nyquist signaling using realizable filters is given. These results are presented in a graphic format which facilitates their use by the system engineer in assessing the design tradeoffs.