4 summary of specifications, 4 summary of specifications 1.4.1 modulator – Comtech EF Data CDM-570 User Manual
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CDM-570/570L Satellite Modem with Optional IP Module
Revision 12
Introduction
MN/CDM570L.IOM
1–11
1.4
Summary of Specifications
1.4.1 Modulator
Modulation
BPSK, QPSK, OQPSK, 8-PSK, 8-QAM and 16-QAM
Symbol Rate Range
4.8 ksps to 3.0 Msps
Data Rate Range
See Section 1.7.5
Operating Modes
Transparent, Closed Network, IESS-315 (VSAT Turbo)
Proprietary EDMAC framed mode:
• 5% overhead – EDMAC
(All modes except BPSK Turbo, Rate 21/44 OQPSK Turbo, and data rates < 2.048 Mbps)
• 1.6% overhead - EDMAC-2
(Rate 21/44, 5/16 Turbo, Rate 21/44 OQPSK Turbo, and all other rates >2.048 Mbps)
Automatic Uplink Power Control (AUPC) mode
R-S Outer Codec (optional)
• 220,200 outer code (transparent mode)
• 200,180 outer code (EDMAC modes)
Turbo Product Codec (optional):
• Rate 21/44 BPSK
• Rate 5/16 BPSK
• Rate 21/44 QPSK/OQPSK
• Rate 3/4 QPSK/OQPSK/8-PSK/8-QAM/16-QAM
• Rate 7/8 QPSK/OQPSK/8-PSK/8-QAM/16-QAM
• Rate 0.95 QPSK/OQPSK/8-PSK/8-QAM (exact Code Rate is actually 0.944)
Transmit Filtering
Per INTELSAT IESS-308 (FIR digital filter implementation)
Scrambling
Transparent Closed Network mode, no R-S or Turbo coding - per ITU V.35 (Intelsat variant)
EDMAC mode, no R-S coding - externally frame synchronized - proprietary
Turbo Product Code mode - externally frame synchronized - proprietary
All R-S modes - externally frame synchronized per IESS-308/309/310
FEC None: Uncoded BPSK/QPSK/OQPSK
Viterbi: k=7, per IESS-308/309
BPSK: Rate 1/2
QPSK/OQPSK: Rate 1/2, Rate 3/4 and Rate 7/8
16-QAM: Rate 3/4 and Rate 7/8 (requires Reed-Solomon)
Reed-Solomon (Closed Network):
220,200 outer code (transparent mode)
200,180 outer code (EDMAC modes)
Interleaver depth = 4
8-PSK/TCM Rate 2/3 (Trellis) with concatenated Reed-Solomon
CLOSED NETWORK - NOT IESS-310 COMPATIBLE
Turbo Product Codec (optional plug-in card):
Rate 5/16 BPSK - 2 dimensional
Rate 21/44 BPSK - 3 dimensional
Rate 21/44 QPSK/OQPSK - 3 dimensional
Rate 3/4 QPSK/OQPSK/8-PSK/8-QAM/16-QAM - 2 dimensional
Rate 7/8 QPSK/OQPSK/8-PSK/8-QAM/16-QAM - 2 dimensional
Rate 0.95 QPSK/OQPSK/8-QAM/8-PSK - 2 dimensional eTPC
(exact Code Rate is actually 17/18, or 0.944)