Hi David, Yep that's a freedv.org signal. It's probably a frequency offset issue. The demod can only acquire a signal with +/- 200 Hz frequency offset, and fdmdv_dec is hard coded to a centre frequency of 1500 Hz. I probably should work out a way to acquire over a wider range or add a manual tuning offset to the command line options.
You could guess the centre frequency and manually adjust FDMDV_FCENTRE in codec2_fdmdv.h, the rebuild. fdmdv_demod Or load the 8kHz raw file up into FreeDV, where you can click on the centre frequency. Thanks, David On Sun, 2012-12-23 at 16:19 -0800, David Ranch wrote: > Hello Everyone, > > I'm new to the list but I've attended a few of Bruce Peren.'s Codec2 > presentations at the local Pacificon conferences. Much to my > pleasure, I spotted what I think was a FDMDV + Codec2 QSO on 20m today > (14.236Mhz). Please note that the transmitting station was created > some splatter that was impacting DRM-based SSTV on 14.233 so I don't > think 14.236 is a safe frequency to use). Anyway, here is a screen > capture of the signal as I was receiving it: > > > http://www.trinityos.com/PRIVATE/Codec2/fdmdv-waterfall-capture.png > > I recorded the signal with Fldigi and thought I'd try to decode it. I > downloaded the current FDMDV code as of today from the Subversion > repository and it compiled right up on my Centos6 platform. I then > tried the following command to decode the WAV files but I didn't get > any real voice out of it: > > sox /tmp/fldigi-codec2-capture.wav -c 1 -r 8k -t raw -s -2 - > | ./fdmdv_demod - - | ./c2dec 1400 - - | aplay -c 1 -r 8000 -t raw -f > S16_LE > > I tried many different permutations of the various commands but > couldn't get any speech out of it. Since I'm not sure where the > I posted the two WAV files here: > > http://www.trinityos.com/PRIVATE/Codec2/ > > > Could anyone help be confirm this was indeed a FDMDV + Codec2 QSO and > what I might have done wrong? > > Ps. Fldigi has a very nice feature to playback WAV files and see it > in the waterfall from the "File" command so this might > > > --David > KI6ZHD > ------------------------------------------------------------------------------ > LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial > Remotely access PCs and mobile devices and provide instant support > Improve your efficiency, and focus on delivering more value-add services > Discover what IT Professionals Know. Rescue delivers > http://p.sf.net/sfu/logmein_12329d2d > _______________________________________________ Freetel-codec2 mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 ------------------------------------------------------------------------------ LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial Remotely access PCs and mobile devices and provide instant support Improve your efficiency, and focus on delivering more value-add services Discover what IT Professionals Know. Rescue delivers http://p.sf.net/sfu/logmein_12329d2d _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
