Operation M7/M7L/M7LT Modular Satellite Modem
1-22 M7/M7L/M7LT - Rev. 0.05
1.6. Forward Error Correction (FEC) Options
The hardware for Viterbi, TCM, Reed-Solomon Codec, and FlexLDPC FEC types are included in the
modulator and demodulator cards, providing the M7 with basic functional capability for all standard
operating parameters including 8PSK TCM and 16QAM. The following sections provide a general
description of the characteristics of each of these functions.
All of the M7 series demodulators have a single plug-on option FEC card for an optional TPC function
or future FEC options.
The Table 1-3 shows the currently available FEC modes and the relation to the modulation types.
Table 1-3 – Modulation, FEC, and Code Rates.
NOTE: The front panel selection number for each of the options is listed as the “Sel #”. For example,
the Modulation modes show the selection numbers 0 through 6, and the FEC Type, Option
and Code Rate selection numbers are listed in the column to the right of each item. These
numbers can be referred for front panel operation but are even more applicable to the SnIP
Telnet command line program named “M7ctl”. This program has specific commands that
BPSK QPSK OQPSK 8PSK 8QAM 16APSK 16QAM
0 1 2 3 4 5 6
None 0 N/A 0 N/A 0 l l l
Viterbi 1 Normal 0 1/2 0 l l l l l
3/4 1 l l l l l
5/6 2 l l l l l
7/8 3 l l l l l
Swap C0/C1 1 1/2 0 l l l l l
3/4 1 l l l l l
5/6 2 l l l l l
7/8 3 l l l l l
CT 2 3/4 1 lu l
7/8 2 lu l
TCM 2 0 2/3 0 l l
TPC 4 Advanced 0 0.453-16k 0 l l l l l
1/2-16k 1 l l l l l
1/2-4k 2 l l l l l
3/4-16k 3 l l l l l l
3/4-4k 4 l l l l l l
7/8-16k 5 l l l l l l
7/8-4k 6 l l l l l l
0.922-16k 7 l l l l l l
0.950-4k 8 l l l l l l
CT 4 5/16 0 l
21/44 1 l l l
3/4 2 l l l l l l
*TPC16k only 7/8 3 l l l l l l
0.95 4 l l l l l l
LDPC 5 Any 0 1/2 0 l l l l l l
Block Size 2/3 1 l l l l l l
256-16k 3/4 2 l l l l l l
Option 0~7 14/17 3 l l l l l l
7/8 4 l l l l l l
10/11 5 l l l l l l
16/17 6 l l l l l l
Modulation Modes (see notes)
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