Comtech EF Data CDM-625A Installation And Operation Manual page 657

CDM-625A Advanced Satellite Modem
Appendix M
•
If required, VersaFEC ACM may be used in conjunction with any of the EDMAC modes,
either for serial remote control of the remote modem, or for SNMP proxy. It should be
emphasized, however, that unlike AUPC, a framing mode is not required for SNR
reporting.
• ACM maximizes throughput not only when Eb/No varies due to atmospheric conditions,
but will also mitigate the effects of other impairments, such as antenna pointing error,
excessive phase noise and certain types of interference. However, rapidly fluctuating
impairments (~ less than 1 second) such as scintillation at low antenna look-angles at C-
band will generally not be improved by ACM.
•
VersaFEC ACM modes are not compatible with VersaFEC CCM modes, due to differences
in frame preambles.
•
The CDM-625A was purposely architected to provide the platform for VersaFEC ACM, and
has required new approaches to the signal processing employed in both modulator and
demodulator. It is the intention of Comtech EF Data to include VersaFEC ACM in future
modem platforms.
M–15
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MN-CDM625A