On 9/12/17, Phil Frost <ind...@bitglue.com> wrote: > I did some experimentation with this technique on BPSK31, and I was able to > get a little more performance in simulations with a matched filter and > trellis decoding than fldigi and PSKCore got with their unmatched filters > designed to minimize the ISI. Though in the case of BPSK31 the ISI isn't > all that bad, so there less than 1 dB of a gain to be had. Perhaps with DMR > there's more potential? >
Hi, On a related note, I've also done some tests between Codec2 voice frames and Opus voice frames. For the tests, Codec2 bitrate was 1300 bits/s while Opus was 19.4 kbit/s Results can be seen here: https://www.youtube.com/watch?v=C9107EA3vNE As far as I'm concerned, Codec2 does amazingly well at voice frequency reproduction (I used a synthesized voice on purpose as I believe it makes it even more difficult for the vocoder.) However, I can see a purpose for Opus, when combined with H264 video, since we are already using a lot of bandwidth for the video frames and the Opus codec does not really add much to it. (the good thing about Opus frames is that they can be reused to multiplex exactly 8 Codec2 frames into timeslots which can be useful when going TDMA). Cheers, Adrian YO8RZZ ------------------------------------------------------------------------------ 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
