Re: [Discuss-gnuradio] DV Dongle - AMBE USB Device

[Eric A. Cottrell]

Jeff Brower wrote:
> Eric-
>
>   
> > ----- Start Original Message -----
> > Sent: Wed, 19 Mar 2008 23:29:57 -0400
> > From: "David I. Emery" <address@hidden>
> > To: Rick Parrish <address@hidden>
> > Subject: Re: [Discuss-gnuradio] DV Dongle - AMBE USB Device
> >
> >     
> > > On Wed, Mar 19, 2008 at 07:38:13PM -0500, Rick Parrish wrote:
> > >       
> > > > Jeff Brower wrote:
> > > >         
> > > > > If you're looking at low bitrate codecs for GNU radio, why use a
> > > > > hardware (dongle)dependent solution? You might look at MELPe, which
> > > > > provides 600, 1200, and 2400 bps,and can be implemented as a software
> > > > > solution. MELPe is a US/NATO standard (STANAG4591). Common
> > > > > applications are HF radio and L band satellite apps where bandwidth is
> > > > > very limited.
> > > > >           
> > > > My interest is what is actually being used - which in the case of public
> > > > safety communications is the P25 variant of IMBE. FWIW, a closed source
> > > > PC hosted IMBE vocoder exists now.
> > > >         
> > >       Is this a DVSI licensed and publically available closed source
> > > module or something "unofficial" or not generally available to the world
> > > at large ?  It has obviously long been possible to recode some reverse
> > > engineered DSP chip based IMBE implemenation into C++ source code for
> > > Wintel/Unix/BSD use, but this would not be free of license and patent
> > > issues... and could not be made part of an open sourced project or
> > > product without a DVSI deal (and it appears they don't see this as in
> > > their interest).
> > >       
> > Hello,
> >
> > In the case of the DV Dongle they buy the DVSI chips and designed a USB
> > interface to connect to a PC.  DVSI gets paid for their work.  It is a
> > neat solution for the problem of providing PC and Network support for
> > D-Star.  The open source part is the interface to the CODEC chip.  It
> > is similar to the MadWiFi drivers where there is a closed source HAL
> > provided by Atheros and the open source part is the interface of the
> > HAL to the OS.  Not the best solution but otherwise there would be
> > nothing.
> >     
>
> Have you seen one of the IMBE dongle codec chips up close?  Is it a TI DSP, 
> maybe
> something like a TMS320VC5509, or similar?  DVSI typically uses TI DSPs.
>
> I'm wondering, because IP rights issues for MELPe go away for 2400 bps rate if 
> a TI
> chip is used; TI will normally waive royalty fees in that case.  Maybe a similar
> approach could be taken for MELPe, it would be cheap and not tied to a radio 
> receiver
> or other equipment.  Just a dongle for GNU radio.
>
> -Jeff
Hello,

This picture of the prototype shows it is a TI chip.
http://www.moetronix.com/dvdongle/

The problem is it may be a ROM or protected Flash version of the DSP 
chip.  I paid for a AMBE codec so I do not want to destroy the internal 
programming,

However this could be used for another project using a TI DSP for a 
MELPe dongle.  The DV Dongle could be a defacto standard for external 
CODEC interfacing.

73 Eric