GNU Radio Companion Prototype for a Dual Analog/Digital Transponder System for the AMSAT GEO Mission

摘要

Our results seem to indicate that it will be acceptable, especially at 10 GHz, to simply add the linear bent-pipe transponder signals to the digital modulated waveform on the downlink from the GEO mission payload so long as it is placed well away from the main lobe of the digital signal, even if run through a hard limiting amplifier, as long as the receiver is narrow-band as compared to the digital signal. In other words, the linear bent-pipe transponder can be carried on the same carrier as the digital signal, thus greatly simplifying the communications system on the payload. This is not a "perfect" solution by any means but it could easily have better IMD performance then the Phase 3 HELAPS transponder.