Comtech EF Data CDM-625A - Page 623

CDM-625A Advanced Satellite Modem MN-CDM625A
Appendix F Revision 4
F–17
F.3 Operational References
F.3.1 Calculate Carrier-in-Carrier Link Budget
Comtech EF Data recommends that you do these steps to calculate the link budget for a CnC
Link:
Step Task
1
Calculate the link budget for both carriers in the duplex link, with required CnC margin:
2 Verify that the PDS ration is within spec for the CDM-625A.
3
Calculate the Allocated Bandwidth (BW) and Power Equivalent Bandwidth (PEB) for the duplex
link:
• BW
Duplex Link
= Greater of (BW
Carrier 1
, BW
Carrier 2
)
• PEB
Duplex Link
= PEB
Carrier 1
+ PEB
Carrier 2
•
Leased BW
Duplex Link
= Greater of (BW
Duplex Link
, PEB
Duplex Link
)
4
For an optimal link, the Leased Bandwidth and the Power Equivalent Bandwidth should be
equal / nearly equal.
5
Repeat the link budget process by selecting different Modulation and FEC, until the BW and
PEB is nearly balanced.