L64724 LSI Logic Corporation, L64724 Datasheet - Page 180

• Manufacturer Part Number: L64724
• Description: Satellite Receiver
• Manufacturer: LSI Logic Corporation

7.3 Reed-Solomon Decoder
7.3.1 Terms and Concepts
7-10
The L64724 Deinterleaver for DSS has the following features:
The Reed Solomon Decoder is a Forward Error Correction (FEC) unit
that looks at the check bytes that are appended to the data stream and
either corrects any errors that it finds in the data stream or asserts the
ERROROUTn pin when it cannot correct the data.
Error Correction Code (ECC) devices have a specific lexicon associated
with their ability to correct transmission messages. This section defines
the terms used for variables in the Reed-Solomon module. The terms are
used throughout this document.
R
The FEC Decoder Pipeline
The minimum separation at the interleaver output is B symbols for
any two symbols that are separated by less than N symbols at the
interleaver input.
Any burst of b < B errors inserted by the channel results in single
errors at the deinterleaver output.
Periodic deinterleaving
Maximum block length of 146 bytes
Deinterleaving depth of 13
Check Bytes
The encoder generates and appends check bytes to the
incoming message according to the Reed-Solomon error
correction encoding. The decoder uses check bytes to
locate and correct errors caused by transmission. The
system designer specifies the size of the check byte field
within the limitations. There are 16 check bytes for both
DSS/DVB modes.