I see. The design choices in 2400A are too low level for me, I mostly write glue code between gnuradio blocks and handle the user interface. If it needs 48 kHz, then this is what I will feed into FreeDV.
Thanks, Adrian On October 23, 2019 8:26:27 PM UTC, Steve <coupaydevi...@gmail.com> wrote: >I'm not sure why 48 kHz was used, other than it makes for a more pure >waveform, and is compatible with sound cards. You need at least 9600 >Hz, as the 4800 Hz tone would need as a minimum 2X to get it sampled. >I suspect 16 kHz would work good in firmware A/D or D/A (without a >sound card). > >The main concept is the tone spacing is at the symbol rate, and that's >what gives it the high performance. I wonder if you changed the first >tone to 400 Hz as then you would have 1600, 2800, and 4000 tones, and >then 8 kHz would sample it correctly. > >Just an idea. If you are using FM then, you want to move the baseband >left anyway, as the FM modulation bandwidth is probably about 16 kHz. > >On Wed, Oct 23, 2019 at 2:28 PM Adrian Musceac <kanto...@gmail.com> >wrote: >> >> So does this mean the input sample rate is also 48 kHz? That would >make it harder for me because all the other modes use 8 kHz... >> >> On October 23, 2019 4:20:48 PM UTC, Steve <coupaydevi...@gmail.com> >wrote: >>> >>> On Wed, Oct 23, 2019 at 10:44 AM Adrian Musceac <kanto...@gmail.com> >wrote: >>>> >>>> >>>> Regarding mode 2400A, can someone confirm that the output of this >mode is resampled to 48 kHz? >>>> I'm trying to add it, but some numbers don't work for me. >>> >>> >>> It's not resampled, it is generated at 48 kHz rather than 8 kHz as >in >>> other modes. >>> Due to the tones being 1200,2400,3600,4800 Hz. >>> ________________________________ >>> Freetel-codec2 mailing list >>> Freetel-codec2@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/freetel-codec2 >> >> _______________________________________________ >> Freetel-codec2 mailing list >> Freetel-codec2@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > > >_______________________________________________ >Freetel-codec2 mailing list >Freetel-codec2@lists.sourceforge.net >https://lists.sourceforge.net/lists/listinfo/freetel-codec2
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