Conclusion; D.10 Conclusion - Comtech EF Data CDM-Qx Installation And Operation Manual

CDM-Qx Satellite Modem
CnCPerformance Characterization
Eb/No Degradation For Asymmetric 4.5-Meter Antenna At A and 2.4 Meter Antenna At B
Eb/No Degradation (dB) @ Site A
Eb/No Degradation (dB) @ Site B
D.10

Conclusion

There are several conclusions for operation with CnC:
•
•
•
•
•
•
•
Eb/No Degradation At Site A
Parameter
CnC Ratio @ Site A
Uplink Fade @ Site A
Uplink Fade @ Site B
Faded CnC @ Site A
Per Figure D-10 QPSK
Eb/No Degradation At Site B
Parameter
CnC Ratio @ Site B
Uplink Fade @ Site B
Uplink Fade @ Site A
Faded CnC @ Site B
Per Figure D-10 QPSK
Operate adjacent carriers with sufficient spacing so there is no degradation.
Adjust the modulation and code rate to alter the CnC ratio
Change the modulation and code rate to scale the symbol rate
Maximum CnC ratio is 7 dB with plenty of margin
Maximum CnC ratio is 10 dB with some degradation
Eb/No degradation is relatively tolerant to fades
QPSK is least sensitive to adjacent carrier and CnC ratio followed by 8-PSK then
16-QAM.
Due To Fade At Due To Fade At
A (dB)
+5.3
6
-
-0.7
0.0
Due To Fade At Due To Fade At
B (dB)
-5.3
3
-
-8.3
0.0
D–14
Revision 6
MN/CDMQx.IOM
B (dB)
+5.3
-
3
+8.3
-0.1
A (dB)
-5.3
-
6
+0.7
-0.1