Consideration of 8-Phase CPSK-TDMA Signal Transmission Through Band-Limited Satellite Channels

The performance of 90- and 108-Mbit/s 8-phase CPSKTDMA channels through a 36-MHz-bandwidth transponder has been evaluated. At the optimum operating point, the error rate of the 90Mbit/s channel is improved by about one order of magnitude relative to that of the 108-Mbit/s channel, and the corresponding carrier power saving is about 3.5 dB. Measurements through a linearized TWT indicate that such a TWTA may be driven harder than a conventional TWTA with a substantial saving in the transponder RF power output. The potential of 8-phase CPSK-TDMA signal transmission through band-limited satellite channels using linearized TWTA's onboard the satellite and modems of the latest technology appears attractive.