Comtech EF Data DMD-2050E Installation And Operation Manual page 82

DMD2050E Universal Satellite Modem
While the traditional link was based on QPSK, TPC 3/4 and required 3.9 MHz of leased bandwidth,
the Carrier-in-Carrier link was based on QPSK, LDPC 3/4 and QPSK, LDPC 1/2 and required 2.8
MHz of leased bandwidth.
The savings summary is as follows:
Item
Data Rate (kbps)
Modulation
FEC
Occupied BW (MHZ)
Power Eq. BW (MHz)
Leased BW (MHz)
Hub HPA (W)
Remote HPA (W)
If this link was designed using QPSK, LDPC 3/4 in both directions, it would have required:
Occupied BW
Power Eq. BW 3.0 MHz 7.2% increase in Power Eq. BW
Leased BW
Hub HPA
Remote HPA
MN-DMD2050E Revision 2
Original Link
Hub to Remote Remote To Hub
3000 1000
QPSK QPSK
TPC 3/4 TPC 3/4
2.8
3.3
26.0
10.6
2.8 MHz
3.0 MHz 7.2% increase in Leased BW
20.3 W
8.3 W 30% increase in Remote power
With Carrier-in-Carrier and LDPC
Total Hub to Remote
3000
QPSK
LDPC 3/4
0.9 3.7 2.8
0.6 3.9 2.5
3.9
Theory of Operation
Savings
Remote to Hub Total
1000
QPSK
LDPC 1/2
1.4 2.8
0.3 2.8
2.8 27.5%
20.3 22%
6.4 40%
3–40