Subjective evaluation of the Intelsat TDMA/DSI

As part of the preoperational testing of the Intelsat TDMA network via the Atlantic Major Path 2 satellite, subjective evaluation tests were conducted for the 64-kbit/s PCM digital speech interpolation (DSI) system. The DSI system performance obtained during controlled stressed loading conditions was assessed by means of an active talker-type subjective evaluation. The equipment configuration, test program structure and subjective test results are presented. The conditions evaluated included a DSI gain of 2.0 for 60 terrestrial input channels.