On 6/10/2010 8:03 PM, J. Moen wrote:
When talking about DV hardware approaches, I have no problem with
D-STAR's use of the proprietary AMBE coded that sells for about $20
per chip in small quantities. It was chosen because it was the best
codec available. Most other DV systems use AMBE chips too.
But when talking about DV software approaches, the AMBE chip does
limit development, not so much because it's proprietary, but because
you can only get it at that inexpensive price on a chip. This greatly
limits experimentation.
So a couple of new codecs legally available to amateurs would be very
welcome. David's codec2 web page also points out the value for
amateur satellites of having open code that could be uploaded to the
sats.
He advocates at least two new codecs, one with better audio quality
and wider bandwidth for use on VHF+, the other using narrow bandwidth
(like MELP) for HF.
If this really happens, there will be a lot of happy amateurs
worldwide. But I am skeptical that it will happen anytime soon. We
are told it is very hard to write quality, workable codecs that work
in a reasonable bandwidth. David's site currently conjectures how to
go about this archtecturally, but this project needs more than good
plans and good intentions. But, I wish him luck.
Jim - K6JM
I think most of us are in total agreement with Jim on these points. We
would love to see open source and unencumbered DV Vocoders. The push
back is only when someone wants to use it to break D-STAR, which has an
installed base and a defined protocol. If someone is successful in
creating a new DV Vocoder, I'm sure many of us will give it a go -- I
will probably be early in the line :)
--
John D. Hays
Amateur Radio Station K7VE <http://k7ve.org>
PO Box 1223
Edmonds, WA 98020-1223
VOIP/SIP: [email protected] <sip:[email protected]>
Phone: 206-801-0820
801-790-0950
Email: [email protected] <mailto:[email protected]>
