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

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SLM-5650A Satellite Modem
Revision 10
Appendix H G–2 MN-SLM-5650A
G.1.1 What is DoubleTalk Carrier-in-Carrier?
The SLM-5650A’s DoubleTalk Carrier-in-Carrier (CnC) option uses a patented signal processing
algorithm developed by Raytheon Applied Signal Technology that allows both the forward and
reverse carriers of a full duplex link to share the same segment of transponder bandwidth, using
patented “Adaptive Cancellation.” Raytheon Applied Signal Technology uses the term
DoubleTalk, and Comtech EF Data refers to it as DoubleTalk
Carrier-in-Carrier (CnC)
1
.
CnC was first introduced in Comtech EF Data products such as the CDM-Qx Satellite Modem,
CLO-10 Link Optimizer, and CDM-625 Advanced Satellite Modem. The implementation of
DoubleTalk Carrier-in-Carrier in the SLM-5650A has been further refined, and some of the
limitations that existed in the prior offerings have been overcome.
CnC technology provides a significant improvement in bandwidth and power utilization, beyond
what is possible with FEC and modulation alone, allowing users to achieve unprecedented
savings. When combined with advanced modulation and FEC, it allows for multi-dimensional
optimization:
•
Reduced operating expense (OPEX) – e.g., Occupied Bandwidth & Transponder Power;
•
Reduced capital expenditure (CAPEX) – e.g., Block Up Converter/High-Power Amplifier
(BUC/HPA) size and/or antenna size;
•
Increased throughput without using additional transponder resources;
•
Increased link availability (margin) without using additional transponder resources;
•
A combination of any of the above to meet different objectives.
Conclusion: When using the DoubleTalk Carrier-in-Carrier (CnC) option, up to 50% savings
in transponder utilization is possible when carriers share common bandwidth.
1
DoubleTalk
®
is licensed from Raytheon Applied Signal Technology.
DoubleTalk
®
is a registered trademark of Raytheon Applied Signal Technology.
Carrier-in-Carrier
®
is a registered trademark of Comtech EF Data.