Comtech EF Data CDM-570A - Manual (Page 528)

CDM-570A/570AL Satellite Modem with Optional Packet Processor MN-CDM570A
Appendix G Revision 2
G–10
G.4.5.1 Symmetric Data Rate Link
Consider the following example:
Satellite & Transponder IS-901 @ 342º W, 22/22 (EH/EH)
Earth Station 1 Africa – 4.5 m
Earth Station 2 Africa – 3.0 m
Data Rate 1.0 Mbps / 1.0 Mbps
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
Link 1 Link 2
Modulation QPSK QPSK
Information Rate (kbit/s) 1000.0 1000.0
FEC Code Rate .875 .875
R-S Code Rate N/A N/A
Clear Sky Eb/No Available 6.3 6.0
Number of Assigned Carriers 1 1
Transmit ES Code HUB REMOTE
Transmit ES Size (m) 4.5 3.0
Receive ES Code REMOTE HUB
Receive ES Size (m) 3.0 4.5
Receive ES G/T (dB/K) 21.5 25.3
Total Leased Resource Usage
LST Calculated
(MultiCarrier Transponder Lease)
Total BW Allocated 1.6000 MHz
TotalBW PEB* 1.5937 MHz
Total EIRP Utilized 15.0 dBw Total BW Utilized 1.6000 MHz
Total EIRP Available 15.0 dBw Total BW Available 1.6000 MHz
Margin (available-utilized) .0 dBw Margin (available-utilized) 0.0000 MHz
*PEB = Power Equivalent Bandwidth
Allocated BW = 1.6 MHz
PEB = 1.5937 MHz
Leased BW = 1.6 MHz
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):