Comtech EF Data cdm-570a - Page 582

CDM-570A/570AL Satellite Modem with Optional Packet Processor
Revision 5
DoubleTalk Carrier-in-Carrier Option G–16 MN-CDM570A
To continue, consider this example:
Satellite & Transponder
IS-901 @ 342º W, 22/22 (EH/EH)
Earth Station 1 Africa – 9.2 m
Earth Station 2 Africa – 4.5 m
Data Rate 2.048 Mbps / 2.048 Mbps
Whereas the original link used 8-PSK TPC 3/4, the Carrier-in-Carrier link used QPSK VersaFEC
0.803.
The savings summary is as follows:
Item
Original Link With Carrier-in-Carrier and VersaFEC
Savings
Hub to
Remote
Remote
to Hub
Total
Hub to
Remote
Remote to
Hub
Total
Data Rate (kbps) 2048 2048 2048 2048
Modulation 8-PSK 8-PSK QPSK QPSK
FEC TPC 3/4 TPC 3/4
VersaFEC
0.803
VersaFEC
0.803
Occupied BW (MHZ)
1.3 1.3 2.6 1.8 1.8 1.8
Power Eq. BW (MHz) 2.2 1.0 3.2 1.1 0.5 1.6
Leased BW (MHz)
3.2
1.8
44%
Hub BUC (W) 5 2 60%
Remote BUC (W) 20 5 75%
Using Carrier-in-Carrier and VersaFEC reduced the leased bandwidth by almost 44% and the
BUC size by 60% at the Hub and 75% at the Remote.