Enhanced Skyplex EQM passes testing

After extensive performance testing, the Enhanced Skyplex Engineering Qualification Model has been fully integrated on Eutelsats W3A Spacecraft and will be launched later this year.

Developed by Alenia Spazio, SkyPlex is the world's first satellite platform to deliver Internet TV services by using a regenerative transponder. When launched it will provide much more flexibility and lower operating costs for Internet Service Providers with respect to traditional satellites platforms. The EQM forms the payload side of this project.


When compared with the standard Skyplex unit (the commercial version), the Enhanced Skyplex EQM is a significant improvement. It is roughly 50% lower in terms of overall mass and size (see image below). Additionally, Hotbirds 4, 5, 6, and Eutelsat W3A used Surface Acoustic Wave Filters (SAW) which were classic analog filters. The new version uses a digital filter to perform the frequency demultiplexing/filtering function (essentially a bank of filters).



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A new demodulator architecture allows the device to operate at a lower signal-to-noise-ratio by using the Turbo decoder. This decoder is compliant with the DVB-RCS Turbo Code and the advantage of Turbo Decoding versus Viterbi Decoding is that at a code rate of 4/5 a coding gain of 5.8 dB is achieved and for a code rate of 6/7 the coding gain is 6.5 dB.


The first Skyplex processor, developed under ESA contract has been in-orbit on Eutelsat's Hot Bird 4 satellite since February 1998. Since then, three second generation Skyplex processors have been ordered from Alenia Spazio (I) by Eutelsat for the Hot Bird 5 satellite, launched in October 1998.


Eight second generation Skyplex processors were order by Eutelsat for the Hot Bird 6 satellite. Five of these second generation Skyplex processors were upgraded to include Turbo Decoders.


ESA started the development of the Enhanced Skyplex with Alenia Spazio (I) and SPAR, now EMS (Cd) in 1998. The Turbo Decoders, now in-orbit on Hot Bird 6, were developed under this contract. The W-series (of which W3A is one) satellites are designed to provide telecommunication services primarily to Europe, Russia and Africa. These satellites are used principally for telecommunication services, mainly business services, satellite news gathering, television and radio programme exchanges.

The W3A spacecraft will be co-located with W3 at 7º East and is designed to offer additional capacity at 7º East as well as to back up W3. The W3A satellite is equipped with 40 transponders and is equipped with four active Skyplex units, identical to the three on Hot Bird 6. They therefore have Turbo coding and cater for 18 carriers at 2 Mbit/s for each unit. The Enhanced Skyplex EQM is also similarly equipped.

Event Date

28 July 2003
Published 17 February 2004
Last updated at 17 February 2004 - 00:00