good . someone who knows the difference between bps and baud. :-) ahh I seem to have misunderstood the bit rate requirement, and radio requirement.
For my audio passband OFDM modems, I used 64 point FFT @ 8000 sps, radios were off the shelf FM 25k links 'flat'. The 125 Hz bins were a little too wide.Needs to be narrow enough that audio passband doesnt change appreciably across a bin of course. I just was picking a nice radix 4... But if you have a whole new radio, I would think 250 Hz bins would provide a pretty good long delay multipath protection / simulcast facility....but with considerable processor cycles lost to setup/ processing overhead each frame. The slower symbol rate say 50Hz as you suggest would provide MUCH better economies of scale for processing overhead per OFDM frame. On 8/11/2017 7:48 AM, Steve wrote: > On Tue, Nov 7, 2017 at 3:59 AM, glen english <g...@cortexrf.com.au> wrote: >> only 1000 bps ish is wanted ? > No. Whatever 5 kHz BW OFDM can provide. That's 80 or so carriers, at > QPSK would be 160 bits 50 times a second, 8000 bps at 50 Baud if my > finger math is working. > 160 bits would get you 64 vocoder + 64 data + 32 protocol bits every 20 ms. > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Freetel-codec2 mailing list > Freetel-codec2@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Freetel-codec2 mailing list Freetel-codec2@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freetel-codec2
