| Abstract: | The expected introduction of new TDMA earth-stations in the EUTELSAT network with a lower diameter antenna, together with the need to ensure the high quality of services are the two principal reasons why regular review of the performance trend of TDMA links is becoming so vital. Such a review will allow overall optimization of the EUTELSAT TDMA system by ensuring that the transponders are operated at their specified points, and will make it possible to be prepared in advance in the event of a transponder gain drop to reconfigure the system with no loss of traffic. To implement these tests, EUTELSAT at its IOT facilities near Paris has installed a burst mode saturation analyser' (BMSA) developed by Hollis Electronics Company. The BMSA has been specially designed as a stand-alone test system for testing TDMA channels in a burst mode without interrupting the operational traffic. This paper describes how the BMSA operates and in particular how the system self synchronizes in order to position the BMSA test burst correctly in the frame, and how the burst is allowed to vary in amplitude in order to characterize the channel under test. This paper also discusses how the BMSA is interfaced to the host IOT station and how the tight measurement accuracy in terms of absolute transmit e.i.r.p. and spacecraft IPFD have been met. The paper concludes by comparing results obtained by classical CW test methods with this new burst method. The conclusions also discuss the limitations of the system and suggest possible improvements. |
