On Sun, Dec 21, 2014 at 12:05 AM, glen english <g...@cortexrf.com.au> wrote: > Easy when you've got a 70K logic cell FPGA, but still possible on > STM32-4, I think you need to come up with a clever way to run the demod
Well keep in mind that there can be multiple target demodulators for this. If a modulation scheme is competitive on a small STM32-4 with the most highly performing scheme you could use with a demod in those constraints it would also be good someone who happens to have 70k LU on an fpga to throw at it (or many fast x86_64 cores) could potentially get a few more dB of low SNR performance. Having a "scalable" setup where people who have huge amounts of money to blow getting small improves can get small improvements-- e.g. by concurrently demodulating with many choices of timing offset and equalizer parmeters and running a big dynamic programming solution over all the error correcting, timing, equalizer, all regularized by stronger statistical speech models than used in the codec, etc.. would serve VHF digital well, because it would allow people with that optimization bug to chase it as far as they want, an would encourage them to get more people producing these signals that their fancy hardware could consume. And if this scaling can be accomplished primarily by adding more commodity cpu power and software (after you've gotten past the initial SDR input), it doesn't require quite the amount of cost ineffective special purpose stuff. (I sort of boggle that people will spend thousands of dollars for fancy radios which are only sold in fairly small quantities and so are fairly expensive for what they deliver, but a modern ham shack does not usually have a half rack of 8 core processors or an FPGA array doing DSP... the returns are diminishing, sure, but cpu power is cheap compared to specialized radio hardware) ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk _______________________________________________ Freetel-codec2 mailing list Freetel-codec2@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freetel-codec2
