This change removes the old copyright header from project sources and
replaces it with a new simplified SPDX-compliant header. Note that files
that were missing the header but reasonably understood to be licensed
according to the root license were not corrected.
Signed-off-by: Ryan Turner <ryan@turnrye.com>
DC removal filter had a bug that created weird positive spikes on
Module17, add a syncword hot re-sync to be able to correct small phase
errors that appear every five seconds more or less.
TG-81
Quantization algorithm is now based on separate rolling averages for
positive and negative samples.
Merged csv outputs from syncword search and quantization on Linux.
TG-81
RRC filter taps have been replaced with the ones generated by Wojciech,
a new baseband for the M17 demodulation testsuite has been generated,
using OpenRTX itself and some further minor changes.
TG-81
Added implementation of the M17 4FSK demodulator, including clock
recovery, phase detection, and quantization algorithms.
A testsuite is also included to do regression testing against a
reference baseband pre-generated and the corresponding reference
bitstream.
A 1% BER is still present due to a fault likely in the RRC filtering,
since the eye diagram of the filtered stream is bad.
TG-81
