Symmetric Data Rate Link - Comtech EF Data CDM-570A Installation And Operation Manual

CDM-570A/570AL Satellite Modem with Optional Packet Processor
Appendix G
G.4.5.1 Symmetric Data Rate Link
Consider the following example:
Satellite & Transponder
Earth Station 1
Earth Station 2
Data Rate
The traditional link was based on QPSK TPC 7/8, and required 1.6 MHz of leased bandwidth
(BW).
The LST (Intelsat Lease Transmission Plan Program) summary for the traditional link is as follows:
Link Analysis Description
Multicarrier Transponder Lease
Number of Links: 2
Modulation
Information Rate (kbit/s)
FEC Code Rate
R-S Code Rate
Clear Sky Eb/No Available
Number of Assigned Carriers
Transmit ES Code
Transmit ES Size (m)
Receive ES Code
Receive ES Size (m)
Receive ES G/T (dB/K)
Total Leased Resource Usage
LST Calculated
(MultiCarrier Transponder Lease)
Total EIRP Utilized
Total EIRP Available
Margin (available-utilized)
Carrier-in-Carrier link design involved trying different Modulation & FEC Code Rates to find the
optimal combination (the CDM-570A/AL also offers 5% to 35% transmit filter rolloffs that can be
used in addition to Modulation and FEC for link optimization):
IS-901 @ 342º W, 22/22 (EH/EH)
Africa – 4.5 m
Africa – 3.0 m
1.0 Mbps / 1.0 Mbps
Link 1 Link 2
QPSK QPSK
1000.0 1000.0
.875 .875
N/A N/A
6.3 6.0
1 1
HUB REMOTE
4.5 3.0
REMOTE HUB
3.0 4.5
21.5 25.3
15.0 dBw
15.0 dBw
.0 dBw
G–10
MN-CDM570A
Total BW Allocated
TotalBW PEB*
Total BW Utilized
Total BW Available
Margin (available-utilized)
*PEB = Power Equivalent Bandwidth
Allocated BW = 1.6 MHz
PEB = 1.5937 MHz
Leased BW = 1.6 MHz
Revision 3
1.6000 MHz
1.5937 MHz
1.6000 MHz
1.6000 MHz
0.0000 MHz