Comtech EF Data CDM-570A Installation And Operation Manual page 664

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If required, VersaFEC ACM may be used in conjunction with any of the EDMAC codes,
eiher 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.
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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.
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VersaFEC ACM modes are not compatible with VersaFEC CCM modes, due to differences
in frame preambles. However, VersaFEC-2 ACM and CCM modes are compatible.
Adaptive Coding and Modulation (ACM) Option
CDM-570A/570AL Satellite Modem with Optional Packet Processor
P–18
Revision 5
MN-CDM570A