Comtech EF Data CDM-760 User Manual
Page 393
Appendix J
Revision 2
CDM-760 Advanced High-Speed Trunking Modem
MN-CDM760
J–15
J.5 Operational References
J.5.1
Calculating a Carrier-in-Carrier Link Budget
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 CnC ratio is within spec for the CDM-760.
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 are equal or nearly equal.
5
Repeat the link budget process by selecting different Modulation and FEC until the BW and PEB is nearly
balanced.