Comtech EF Data SDR-54A - Manual (Page 17)

SDR-54A Satellite Demodulator Revision 4
Introduction MN/SDR54A.IOM
The LNB converter is mounted directly to the antenna and preserves received signal-to-
noise while providing gain and frequency down conversion. This feature minimizes signal
degradation between the antenna site and demodulator. An appropriate LNB must be used
in order to properly operate the demodulator. LNB primary power is provided by the
demodulator via the coaxial signal interconnect. See Chapter 8 for LNB specification
information.
IMPORTANT
A fully compatible LNB is available from Comtech EF Data. Contact Comtech EF
Data Customer Support representative for more information.
L-Band input frequencies are tunable from 950 to 1550 MHz, in graduated steps of
10 kHz. The demodulator will lock to a carrier within the frequency stability range of the
receive system (± 500 kHz), and will perform coherent detection for QPSK and BPSK
modulation.
Forward Error Correction (FEC) is provided by the demodulator’s integrated Viterbi
decoder, which can support 1/2, 3/4, and 7/8 rate coding, along with the optional
Reed-Solomon.
Digital data output is selectable between synchronous RS-232 or RS-422 format. Data
rates from 4.8 to 1250 kbps for BPSK and 9.6 to 4000 kbps for QPSK. The demodulator is
compatible with the following:
• INTELSAT open network filtering
• Comtech EF Data closed network filtering
• SDM-51, -52
Monitor and control of the demodulator is provided by a user-accessible RS-232 serial
port. Once configured, power may be removed for at least 1 year and reapplied without
loss of configuration.
The demodulator incorporates features for remote configuration over the satellite channel
using Comtech EF Data’s Space Link Remote Control (SLRC) protocol.
For more information about the SLRC, refer to the Comtech EF Data Space Link Remote
Control System User’s Guide.
Provisions for optional demultiplexers are as follows:
• Option 1: Synchronous/symmetrical DEMUX 2- or 4-channel. Maximum tributary
data rates of :
1–3