Digital Transmission Evaluation Project Universal Loop Multiplexer ULM-101.

摘要

Testing of the ULM-101, Universal Loop Multiplexer, was initiated to establish a data base and assessment of the Continuous Variable Slope Delta (CVSD) and log CVSD modulation techniques and to evaluate its ability to process signals typical of those used in the Defense Communications System (DCS). Tests of voice channel performance showed, in general, that minimum DCS standards were met at 32 or 64 kbps channel sampling rates. Performance was marginal and unacceptable at 16 and 8 kbps rates, respectively. Voice Intelligibility Test results are not yet available. DCEC is expected to publish these results. Use of various quasi-analog signal sources resulted in good to unacceptable performance depending on the channel sampling rate and type of signal source. Performance was not severely degraded when operating in an error environment. (Author)