Comtech EF Data SDM-2020 - Manual (Page 18)

SDM-2020 Satellite Modulator Revision 7
Introduction MN/SDM2020M.IOM
1-2
The modulator utilizes a plug-in data interface module installed in the rear of the chassis.
The data interface module provides flexible adaptation to the various physical and
electrical interfaces found in the communications industry.
The modulator utilizes Fully Accessible System Topology (FAST), Comtech EF Data’s
new feature for immediate implementation of different options through the user interface
keypad. FAST enable on-location upgrades of the operating feature set—in the rack—
without removing a unit from the setup. This feature employs a unique access code to
enable configuration of the available hardware. The access code can be purchased at any
time from Comtech EF Data. Once obtained, the access code is entered into the unit
through the front panel keypad or the rear remote port. When service requirements
change, the modulator can be upgraded to meet the new requirements within minutes
after confirmation by Comtech EF Data.
The data rate of the modulator is programmable from 1.5 to 100 Mbit/s depending upon
the data interface and the maximum symbol rate is 37.5 Msym/s. The minimum symbol
rate is limited by the minimum 1.5 Mbit/s data rate. Modulation formats include QPSK,
8PSK, and 16QAM. Operation is based upon the DVB/DBS standard for QPSK and
8PSK.
Table 1-1 lists the minimum and maximum data and symbol rates for each code rate. See
the specifications section for the maximum data rate limits by framing types.