Like a frequency hopper (FHSS) you want it to hit all the tones, and not send CW.
I haven't examined the codec 2 vocoder bits when no audio is input. I'm assuming it cycles through all four tones. I can see where telemetry data would need a scrambler though. On Fri, Jun 15, 2018 at 12:38 AM Mark Jessop <lenniethelemm...@gmail.com> wrote: > > The current version of the Horus Binary modem using both a scrambler and an > interleaver. > > Without the scrambler you can end up with long runs of zeros depending on the > payload contents. Maybe it doesn't affect the modem, but it sure doesn't > sound right! > > 73 > Mark VK5QI > > On Fri, Jun 15, 2018 at 10:03 AM, David Rowe <da...@rowetel.com> wrote: >> >> We've used this FSK modem quite a lot for balloon telemetry and have >> wondered from time to time if we need scrambler. So far we have never found >> "the smoking gun" which would be the timing estimator falling over. >> >> Having said that I think we may have included a scrambler in one version of >> the telemetry. >> >> A related problem is burst operation ... how to get timing sync just as a >> signal starts. >> >> - David >> >> >> On 14/06/18 23:02, Steve wrote: >>> >>> On Thu, Jun 14, 2018 at 12:14 AM David Rowe <da...@rowetel.com> wrote: >>>> >>>> >>>> Just want to point out that, last time I tested them, the 4FSK waveforms >>>> work just fine - unmodified and without a scrambler. >>> >>> >>> It was just a what-if that was suggested as an experiment. I'm over it now. >>> >>> ------------------------------------------------------------------------------ >>> 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 > > > ------------------------------------------------------------------------------ > 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
