Comtech EF Data CDM-625A User Manual

Page 691

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CDM-625A Advanced Satellite Modem

MN-CDM625A

Appendix M

Revision 3

M–11

Figure M-3. CDM-625A – ACM ModCod Switch Points

The Figure M-3 graph shows the switch points with the Target Eb/No margin set to 0dB.

However, the switch points can be moved (increased) by configuring the Target Eb/No margin

parameter, which can vary from 0 to 4.5 dB, in 0.5dB steps. In a fading environment, it is

strongly recommended to add sufficient margin to maintain an adequate link quality (and to

maintain demod lock) during the interval between the Eb/No degrading and the ACM controller

responding by lowering the ModCod. See Section M.11 Notes and Recommendations.

To continue with the configuration:

Step

Task

Front Panel Mnemonic

6

(SELECT) CONFIG: IP Switch-set-up WAN

Enter the

desired size of the WAN Buffer. The

minimum size is 20 milliseconds, and is referred to the
data rate corresponding to ModCod0.

In order to

achieve minimum system latency, do not make this

value unnecessarily large. . Note that this does not

apply if the Packet Processor Card is installed.

Ethernet Switch: Mode WAN PerPortCnfg

MAC-Learning VLAN Qos Stats (

)

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