Wideband line-of-sight channel simulator

This report describes the theoretical background, methods of implementation, and utility of a multi-purpose wideband LOS (line-of-sight) channel simulation system developed by CNR, Inc. for Rome Air Development Center as a means for evaluating wideband digital modems. The system provides both a channel probing/channel playback capability and a synthetic stochastic channel simulation. Propagation media effects simulated, include both multipath due to refractive anomalies (refractive multipath) and scattering off the surface (surface multipath). The types of LOS channels handled by the system include airplane-airplane, ground-airplane, ground-ground, and airplane-satellite. In addition, the simulator allows the introduction of controlled amounts of nonlinearity, phase jitter, and frequency offset. The simulator operates at selectable IF frequencies of 70, 300, or 700 MHz. At the two high IF frequencies, signal bandwidths up to 100 MHz may be accommodated, while at 70 MHz, bandwidths up to 25 MHz may be handled.