J.83abc/DVB-C Cable FEC Decoder

The CMS0018 J.83abc/DVB-C Cable FEC Decoder combines all of the channel coding and Forward Error Correction functions specified by DVB-C and by J83 – Annexes A B and C

The CMS0018 includes functions for QAM constellation slicing, trellis decoding, de-framing, de-scrambling, de-interleaving, and Reed-Solomon decoding.

With the exception of the common de-interleaver block, two independent datapaths are required. J83A J83C and DVB-C are quite similar in requirements. These are implemented in the DEC_A sub-block

The requirements of J83 Annex B are significantly different. The largest difference is the addition of trellis coding, but the Reed-Solomon code is also uniquely different and the scrambler is based on a different algorithm. In practice, only the de interleave block may be easily shared between them.

• Provides the required channel coding functions for cable television as specified by ITU Recommendation J.83 Annexes ABC and DVB-C.
• Configurable I/Q input width
• Standard 188-byte MPEG Transport Stream output.
• C / C++ header file defines Host Interface registers, allowing software mode control.
• External RAM interface for long interleave modes.
• Synthesis control to build for any subset of the supported modes, removing unneeded logic.
• Optional BER monitor provides statistics on Errors Corrected and Residual Packet Errors.