Hi,
Just want to point out that, last time I tested them, the 4FSK waveforms
(FreeDV 2400A, and 800XA) work just fine - unmodified and without a
scrambler.
800XA is being used by people over the air - in fact I'm working with
some UK Hams on exciting high power experiments using simple and compact
Class E amplifiers. There is a lot of link margin possible compared to
OFDM waveforms through linear PAs.
Now 800XA is a FreeDV GUI mode that anyone can run ..... pls feel free
to try it.
Two years ago Brady ran 2400A (using a 4FSK modem) on the SM2000
prototypes which use the stm32 - Glen IIRC you were in the Gipstech
audience :-)
So what we have is:
i) Code that works on the x86 platform
ii) Code that doesn't on the stm32
This suggests a porting issue to me. Steve - happy to work with you on
a series of unit tests to take us from x86 FreeDV API cmd line test
programs to working code on the stm32. It is possible there is some
corner case that we are missing, if so some careful unit tests will show
that up.
Cheers,
David
On 14/06/18 13:20, Steve wrote:
Yes. You can't see it on the FreeDV spectrum display, as that display is
filtered and averaging. But I'm sure an oscillator or two disappears.
This particular scrambler resets itself every frame. It has a starting
bit pattern. So every modem frame starts-off with the same value, and is
only 64 bits long (two codec frames). So errors may only be 80 ms in
length, before the next modem frame.
The additive scrambler for HORUS was taken out of wikipedia
1+x^{{-14}}+x^{{-15}}
On Wed, Jun 13, 2018 at 10:37 PM glen english <g...@cortexrf.com.au
<mailto:g...@cortexrf.com.au>> wrote:
The downside of most scramblers (I dont know what is used here) is that
you can get error propagtion in a scrambler.
------------------------------------------------------------------------------
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
