JT44 vs CW simulation
- Hello all.
This is just a brief note to say that at the request of several EMEers I
have added two CW files to my JT44 Simulation webpage, which is at
http://www.qsl.net/w3sz/JT44.htm . They are near the bottom of the page,
just after the list of JT44 test files.
What I did was to create 2 CW-in-the-noise files with the signal-to-noise of
the cw the same as the signal-to-noise where JT44 had good copy. One file,
test52cw.wav has cw at -52dB with the noise at -54 dB, and the other
test48cw.wav has cw at -48 dB with the noise at -54 dB. These are the first
two levels where JT-44 achieved single-exchange complete copy (although JT44
did complete copy at lower signal levels with averaging).
I find I can see the cw signals at these levels with Linrad, spectran, and
dsp-blaster, as well as with fftdsp, but so far neither I nor anyone else
has copied the cw in the files correctly.
Please note that these files are long- 2 to 2.5 minutes in length, as
shorter file durations made trying to copy the messages more difficult.
Because of their length, both files are in zipped format on my website.
Any comments appreciated, especially if you think you've broken the code on
one or the other of the files. Remember-assumptions can be dangerous ;)
If you think you've broken the code, please reply to me directly and not to
the list, so as not to 'spoil the fun'.
2 Merrymount Road
Reading, PA 19609-1718