Re: Yaesu AMBE chip

"John D. Hays" <john@...>


My reading of the Yaesu spec is that type 2 adds some FEC bits, external to the AMBE+2 vocoder.  My suspicion is that they are applying those addition FEC bits to the AMBE sample but having the AMBE-3000 chip only handle the 'standard' HR packet.  I'll look into it further.

Also are you using the RATET commands to set the register values or individually setting them using RATEP? (Page 64 of the 3000F manual)

On Mon, Nov 16, 2015 at 12:46 AM, beaupeppybrandypip@... [UniversalDigitalRadio] <UniversalDigitalRadio@...> wrote:

ah !

Thank you John. Fresh samples !

The DN file is V/D type 2.
I've just looked at the DR-1X manual and see that Yaesu don't give you the option to specify which of the two HR modes (V/D type 1 or V/D type 2) it uses, which is a shame.

I can decode the DN voice OK by feeding the extracted voice channel bits to the software mbelib AMBE decoder, but when I feed them to the hardware AMBE-3000 chip it doesn't decode it correctly still (comes back garbled).

So, either Yaesu are using a none standard AMBE-3000 chip, or I've still got something wrong, or they have chosen not to document a required step before sending the voice channel bits to the AMBE-3000 chip.

Considering that encrypted/hidden voice or data transfers are forbidden on the ham bands, I'm surprised the radio manufactures are getting away with not making every protocol detail freely availabe (such as what happened with ICOM/DSTAR).

Anyway, I shall keep at it, because I can't yet rule out that I'm forgetting something or have got something slightly wrong.

For Fusion V/D mode type 2 (a HR mode), I'm setting the AMBE-3000 chip to a custom rate using the these parameters listed in the chip data sheet ..

Total rate    Speech rate   FEC rate   RCW0    RCW1    RCW2    RCW3    RCW4    RCW5
   2450           2450             0           0x0431   0x0754   0x0000   0x0000   0x0000   0x7031

And for Fusion FR mode I'm using ..

Total rate    Speech rate   FEC rate   RCW0    RCW1    RCW2    RCW3    RCW4    RCW5
   7200           4400           2800        0x0458   0x0986   0x8020   0x0000   0x0000   0x7390


John D. Hays

PO Box 1223, Edmonds, WA 98020-1223 

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