Hi All,
I have modified WSJTX 2.0.0 (old version rather than 2.0.1 because I
don't want to switch versions mid project) to produce 12000 samples per
second wav files for data analysis.
The files produced work properly for every mode, both fast and slow,
except for JT4. I did not mess with any mode-specific code.
The JT4 files produced decode properly if they are run in a program such
as CoolEdit and sent to WSJTX via VAC, but fail to decode if run by
using the File>>Open>>read_wav_file facility of WSJTX, even though the
waterfall that they produce looks identical to the waterfall produced
when CoolEdit is feeding WSJTX. The problem wav files give no error
message, and produce a normal-appearing waterfall, and WSJTX does
attempt to decode but I get an non-decode message like "0000 22 -1.0
700 $*" in the Single Period Decodes window for JT4. And the dB report
is 12-20 dB lower than expected
Also, if I have WSJTX produce 48000 samples per second sampling rate
files and then decimate them to 12000 using MATLAB I get the same
result; with this method as well all modes work properly except for
JT4, which behaves exactly as just described above.
The JT4 wav files "saved" by WSJTX after a successful decode of one of
the problem JT4 wav files sent to WSJTX from CoolEdit work properly
using the WSJTX File>>Open>>read_wav_file facility.
I am hoping that someone has run into some similar problem before or has
an idea about what the problem may be. I've been over the code and am
stuck.
Here is some data:
waterfall showing CoolEdit input on the bottom and WSJTX
File>>Open>>read_wav_file input on the top:
http://w3sz.x10.mx/WSJTX/1-JT4GLowerTraceFromCoolEditUpperTraceDirectFromFileToReceiveWSJTX.PNG
As noted above, the bottom trace decoded and the top one did not.
waterfall running audio output of one instance of WSJTX to input of
another via VAC, same signal as above (strength is much greater but I
get same results with all reasonable signal levels):
http://w3sz.x10.mx/WSJTX/1-JT4GDirectFromNormal2pt0pt0ToReceiveWSJTX.PNG
12000 sampling rate wav file produced by modified WSJTX:
http://w3sz.x10.mx/WSJTX/JT4_12000_FromModifiedWSJTX.wav
12000 sampling rate produced by standard version of WSJTX when it
decodes above (input via CoolEdit)
http://w3sz.x10.mx/WSJTX/190404_0233a.wav
I produced the 12000 sampling rate files in WSJTX by modifying
Modulator.cpp, changing TX_SAMPLING_RATE to 12000, and then making the
necessary housekeeping changes to Modulator.cpp associated with the
above. It is likely that I did something stupid to cause this problem,
I just can't figure out what that is.
My code is here:
http://w3sz.x10.mx/WSJTX/Modulator.cpp
A comparison with the original code is here (original is on the left):
http://w3sz.x10.mx/WSJTX/DiffModulatorDotcpp.htm
I don't think it could be a header problem because all of the other
modes work fine, but just in case here is some header info below.
The header section of a problem wav file is in the first 44 bytes of
this pdf:
http://w3sz.x10.mx/WSJTX/JT4GdotWAVfromModifiedWSJTX_HEX.pdf
and the header from the "good" wav file WSJTX saved after decoding the
above is here:
http://w3sz.x10.mx/WSJTX/JT4GdotWAVsavedFromStandardWSJTX_SuccessfulDecode_HEX.pdf
Thanks in advance, and
73,
Roger Rehr
W3SZ
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