Comtech EF Data Vipersat SLM-5650A, Installation And Operation Manual

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SLM-5650A Satellite Modem
Revision 10
Appendix H G–1 MN-SLM-5650A
Appendix G. OPTIONAL
DOUBLETALK CARRIER-IN-
CARRIER
BEFORE YOU ATTEMPT TO COMMISSION A SATELLITE LINK USING CARRIER-IN-CARRIER
(CnC), YOU MUST ENSURE THAT THE LINK IS ROBUST ENOUGH FOR NORMAL
OPERATION. ONLY WHEN YOU HAVE DONE THIS – AND YOU RESOLVE ALL SYSTEM
ISSUES (E.G., ANTENNA-POINTING, CABLING, TERRESTRIAL INTERFERENCE, SATELLITE
INTERFERENCE, ETC.) – SHOULD YOU ATTEMPT THE USE OF CARRIER-IN-CARRIER.
G.1 Overview
Space segment costs are typically the most significant operating expense for any satellite-based
service, having a direct impact on the viability and profitability of the service. For a satellite
transponder that has finite resources in terms of bandwidth and power, the leasing costs are
determined by bandwidth and power used. Therefore, a satellite circuit should be designed for
optimal utilization to use a similar share of transponder bandwidth and power.
The traditional approach to balancing a satellite circuit – once the satellite and earth station
parameters are fixed – involves trade-off between modulation and coding. A lower order
modulation requires less transponder power while using more bandwidth; conversely, higher
order modulation reduces required bandwidth, albeit at a significant increase in power.
Comtech EF Data’s DoubleTalk Carrier-in-Carrier option adds a new dimension to satellite
communication optimization.