ATSC-M/H Signal Error Detection and Correction Algorithms
ATSC and ATSC-M/H share the same physical layer (RF) but ATSC is optimized for stationary reception but not for mobile reception. Therefore the ATSC-M/H data portions within the ATSC+ATSC-M/H multiplex are coupled with a chain of extremely high complex error correction mechanisms:
- Viterbi algorithm
- Turbo Codes – SCCC and PCCC
- Reed Solomon algorithm
All these algorithms increase the signal robustness significantly so that mobile reception is possible.
SAMcorder, the central input/output data processor of decontis’ atscSAM analysis and monitoring solution, supports all these error correction algorithms, independent on whether the signal is received via RF, IP, ASI or comes from a captured Transport Stream. Additional optimizations and error corrections have been implemented to maximize reception robustness, which even go beyond the standard specification.
The following short video sequences demonstrate how the M/H signal error correction improves reception. The left video snapshot has been received using a Hauppauge HVR-950 USB stick under poor reception conditions. The right video snapshot shows the identical video after processing lively the ATSC-M/H error correction algorithms on it.
|reception without error corrections||reception with error corrections|
Analysis and Monitoring
All signal error corrections are analyzed in real-time and the results can be monitored via SNMP.
– detection of M/H slot synchronization errors
– Bit Error Ratio after Viterbi
– number of bytes which could be corrected as well as not corrected by the Reed Solomon algorithm
– number of wrong detected M/H PIDs which have been corrected