MMTTY offers 4 different RTTY demodulators, with configurable filter shapes
for each. Configurable bandpass and notch filters are also provided. The
AA6YQ-FIR-512 profile yields the best weak signal decoding attained so far
with MMTTY.
MMVARI offers 2 RTTY demodulators, with a choice of 4 bandpass filter
widths. The FFT demodulator with the ~200 hZ bandpass filter yields the best
weak signal decoding attained so far with MMVARI.
Using a -10db SNR file generated by Moe AE4JY's Pathsim, I used Alex
VE3NEA's RTTYcompare to compare MMTTY's weak signal decoding with MMVARI's.
Configured as described above,
- MMTTY produced an 18% character error rate
- MMVARI produced a 19% character error rate
MMVARI's weak signal decoding is not better than MMTTY's when both are
configured optimally.
73,
Dave, AA6YQ
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