Comtech EF Data CDM-760 - Manual (Page 353)

Appendix G Revision 2
CDM-760 Advanced High-Speed Trunking Modem MN-CDM760
G–19
G.5 CDM-760 ACM Configuration and Operation
G.5.1 CDM-760 Operational Overview
ACM operation is a FAST option that must first be ordered, and then activated in
the CDM-760 High Speed Trunking Modem. If this option is not enabled in the
modem, contact your Comtech EF Data Sales Representative to upgrade the
modem to support the desired level of ACM operation.
Table G-5 and Table G-6, provided in Sect. G.4.6, list the minimum and maximum modem
symbol rates and associated data rate capacity when in ACM mode.
With ACM operation enabled, Tx and Rx Symbol Rates can be set to any rate desired up to the
maximum purchased symbol rate in 1 sps steps.
CAUTION: When considering ACM operation, note that the symbol rate of the
carrier chosen can limit higher order modulation schemes from running.
For example: Although you can configure the modem to run ACM operation at 100
Msps, with this size carrier, 16APSK and 32APSK will never be attained as the
symbol rate limitation for these modulation types is 90Msps and 72Msps
accordingly. For most geostationary, non HTS (High Throughput Satellites)
systems, even the largest transponders can only accommodate a carrier that is
72Msps or less, so this is typically not an issue.
Actual user data rate throughput will be at least 99% of the maximum satellite data rate
capacity when running in GSE Ethernet encapsulated mode. ACM mode is suggested to run only
in Normal (64,800 bit) frames with pilots ON.
You can configure, monitor and control ACM operations in the following ways:
• Local Control via the CDM-760 Front Panel keypad and VFD.
• Remote Control with a user-supplied PC via the:
o
CDM-760 HTTP (Web Server) Interface using a compatible Web browser.
o
Ethernet-based Simple Network Management Protocol (SNMP) using a Network
Management System (NMS) and Management Information Base (MIB) File Browser.
o
Serial-based Remote Product Management.
USE OF THE ETHERNET-BASED SNMP AND SERIAL-BASED REMOTE CONTROL
INTERFACES ARE RECOMMENDED ONLY FOR ADVANCED USERS. COMTECH EF DATA
STRONGLY ENCOURAGES USE OF THE CDM-760 FRONT PANEL OR HTTP (WEB
SERVER) INTERFACE FOR MONITOR AND CONTROL (M&C) OF THE CDM-760.