Comtech EF Data CDD-880, Инструкция по установке и эксплуатации

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CDD-880 Multi Receiver
Router
MN-CDD880
Appendix H Revision 2
H–10
• Seconds since last LQRM – This is how long in seconds it has been since this unit
received an Es/No report from the CDD-880.
•
Max Seconds since last LQRM – This is useful to understand if there are long durations
of not seeing the report messages.
•
IP Source of last LQRM – This is the Management IP address of the CDD-880 which is
sending this unit LQRMs.
•
Last Report Es/No – This the Es/No measured at the CDD-880 and sent to the CDM-840.
•
Current MODCOD – This is the MODCOD that this unit is currently sending.
•
Current Datarate – The Current Datarate will update as the MODCOD changes in order
to maintain the link.
Alternately, if you have access to an Oscilloscope in X-Y mode, the ‘ ALARMS ’ connectors,
located on the rear panel of the CDD-880 or the CDM-840, provide analog voltages to monitor
the constellation. This permits you to view a change in modulation type instantaneously.
If you wish to verify that link performance is meeting the required level, the CDD-880 and
CDM-840 HTTP Interface “ Utility | Utility” pages ( Figure H-6 ) feature a BERT function. It is not
an easy matter to verify BER performance using the HTTP Interface. The internal BERT not only
verifies BER performance, it also tolerates the change in bit rate that accompanies the change in
MODCOD. Use BERT to confirm that there are no sync losses or bursts of bit errors when a
MODCOD changes.
Figure H-6. HTTP Interface – Utility | Utility Page (CDD-880 Shown)