Comtech EF Data SDM-300A - Manual (Page 237)

9–1
Chapter 9. Forward Error
Correction (Options)
9.1 Introduction
As standard, the SDM-300A is equipped with four Forward Error Correction (FEC)
encoders/decoders – Viterbi, Sequential, concatenated Reed-Solomon, and Trellis (which
is available with the 8-PSK FAST option). The constraint lengths and encoding
polynomials are not only Open Network compatible, but also are Closed Network
compatible with the vast majority of existing modems from other manufacturers.
Comtech EF Data has performed compatibility testing to ensure inter-operability.
Turbo Coding represents a very significant
development in the area of FEC, and optionally,
the SDM-300A may be fitted with Turbo
Product Code. The Turbo card is a plug-in
daughter Card (SIMM
modules), located in the same slot as the Reed-Solomon cards (Reed-Solomon cards shall
be removed.) Turbo may be field upgradeable.
• The Turbo option provides data rate capability up to 5 Mbps, and code rates
limited to:
BPSK Rate = 5/16 or 21/44
OQPSK / QPSK Rate = 1/2, 3/4
8-PSK Rate = 3/4
Turbo Product Coding provides the best Forward Error Correction technology currently
available, and is now offered with a sufficient range of code rates and modulation types
that link performance can be optimized under any conditions.