摘要：

This research is a study of the performance of Army voice circuits in the transitional DoD telecommunications system of the l98O's. Transmission, switching and user terminal facilities will be converted from analog to digital operation during the next two decades. Voice circuits will be composed of various tandem (series) connections of pulse code modulation (PCM), continuously variable slope delta (CVSD) and vocoder links. The purpose of the research is to determine if the system design for the 1980V5 results in isolated pairs of users. The approach is to examine the technical characteristics of digital voice links, to consider the system plans of the Services and DoD Agencies, to evaluate the mode of interoperability at the boundaries which join the several regions of the overall DoD system, and to analyze the signal-to-noise ratio (SNIR) performance of tandem-link circuits within the U.S. Army system. The study concludes that some isolated pairs of users will exist in the transitional system, but the occurrence of isolated pairs of users may be minimized by providing digital transmission paths to directly interconnect communities of 16 kB/s subscribers. The principal recommendation of the study is that tandeming of voice links should be minimized.

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