5 Commits

Author	SHA1	Message	Date
Steven Franke	b087328fc1	Don't waste time on excess BP iterations when doing K=50. Decode a little deeper.	2021-01-04 15:00:03 +00:00
Steven Franke	11b7aa9429	Implements decoding of FST4W messages as (240,50) crc-less codewords. ... By cascading the full 24-bit crc generator matrix with the (240,74) LDPC code generator, create a (240,50) generator that is used to decode with approximately 1 dB better sensitivity than the (240,64) with 14-bit CRC approach that is normally used. This approach treats the CRC bits as additional parity bits and provides no means for identifying incorrect codewords. All codewords on the list generated by the OSD algorithm have CRCs that match the CRC of the message payload. Codewords are validated by unpacking the message and comparing the unpacked message with the list of stored callsign/grid pairs stored in the fst4w_calls.txt file.	2021-01-04 14:59:56 +00:00
Steven Franke	b9328b96c9	Tweaks to update the diagnostics that are written to fort.21.	2020-08-29 19:55:22 +01:00
Steven Franke	bf06193c10	Add timer call for bit metric calculation. Improve some comments. Make fort.21 ntype parameter more informative.	2020-08-29 19:54:38 +01:00
Steven Franke	085e63e05d	Rename fst240 to fst4 in Fortran routines.	2020-07-23 12:48:50 -05:00