RADC-TR-75-95 (VOL I OF II), FINAL TECHNICAL REPORT: EQUIVALENCE MEASUREMENT STUDIES (SECTIONS 1 - 4) (APR-1975)

RADC-TR-75-95 (VOL I OF II), FINAL TECHNICAL REPORT: EQUIVALENCE MEASUREMENT STUDIES (SECTIONS 1 - 4) (APR-1975)., This report describes the results of an investigation concerned with developing and evaluating concepts for channel quality monitoring of advanced digital data transmission techniques over four fading dispersive channels of interest to military communications: the line-of-sight ground point-to-point microwave relay, troposcatter, satellite ionospheric scintillation, and high-frequency long haul channels. The study emphasis is on a monitoring subsystem called the Media Quality Unit (NQU) which continually estimates long- and short-term error rates for a non-degraded receiver and by comparison with actual error rate as measured by a Performance Monitor Unit (PMU) allows estimation of receiver degradation trends and classification of outages into receiver-, media, or interference-caused. Major effort was devoted to development and analysis of MQU techniques which utilize the received information-bearing signal alone as a source of channel information since continuous on-line operation is possible and no sp. :ial probing signals are required. However, some attention is given to special probing signals and their application to each of the channels of interest. For all channel parameter and error rate estimation techniques, the measurement accuracy was determined as a function of processing bandwidth, averaging time, and channel parameters. Consideration is given to implementation alternatives for the MQU in terms of analog, digital hardware, and small computer processing.