MODEM TESTING WITH A MULTIPATH TRANSMISSION SIMULATOR.

This report covers the results of several on the bench tests performed on engineering test models of modulatordemodulator MD-515. The MD-515 is a 12 channel, phase shift keyed psk data modem designed to operate at either 2400 or 1200 bps. In the 1200 bps mode, the option of either in-band frequency diversity or double baud length signaling elements is available. The first series of tests involved the use of a multipath transmission simulator to evaluate the performance of the modem under controlled conditions of selective fading and phase perturbations. Other tests were performed by adding noise to the line signal to measure the error rate vs signal-to-noise ratio, the dynamic range of the equipment and the effect of peak limiting the line signal prior to transmission. A brief description of the modem and the simulator are included in the report. Author