Re: Yaesu AMBE chip

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

Hi Cath,

I have not seen documentation on V/D mode 2.  Perhaps I missed it somewhere.

I am aware that it's important that you pace the packet stream to/from the AMBE3000 chip by waiting for the AMBE packet when sending in the PCM packet and vice versa.

On Sat, Nov 14, 2015 at 7:02 PM, beaupeppybrandypip@... [UniversalDigitalRadio] <UniversalDigitalRadio@...> wrote:

Hello John

Thank you for your reply :)

Yes 33 is the one I see it as being as well John.

Well, their are 3 different rates Yaesu use ..

 3600 .. 2450 voice .. 1150 fec .. V/D mode 1 .. index 33
 2450 .. 2450 voice ..      0 fec ...V/D mode 2 .. index 34
 7200 .. 4400 voice .. 2800 fec ..  FR mode ......index 59
    all AMBE+2

The index rate numbers are the only ones I can see them as being.
Am hoping it's the standard AMBE-3000R chip they use, especially as they have freely
published the protocol specifications they use (unlike DSTAR).

I am decoding and extracting all the data from the raw C4FM fusion frames that I currently have at hand, can decode/decompress the Fusion 2450 V/D type 2 mode voice using the software mbelib just fine, but am having trouble getting the AMBE-3000R chip to decode the channel bits back into audio samples. The chip gives me the audio samples back OK, just not in any kind of human speech language known to me lol.

If use the AMBE chip (the ThumbDV) to encode/compress speech, it then decodes it as expected. So all's fine there (using any rate setting).

I'll keep at it though until I find out exactly whats going on.


John D. Hays

PO Box 1223, Edmonds, WA 98020-1223 

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