[Allstar Digital] DMR, DSD, DVSI MMDVM oh my

[Steve Zingman]

Robert,
As a system, there is no documentation you can read. You want to look at 
the parts and then understand how this goes together.
Start with a analog receiver listening to a DMR signal feeding 
discriminator audio to a sound fob or URI plugged in to a RPi.
The RPi is running DSD under Linux listening to the URI.
DSD unmodified uses a software based AMBE decoder. That decoder software 
is a violation of DVSI copyright. So we replace it with the DV3000.
DSD modified sends the AMBE packets to a DV3000 mounted on the RPi. The 
DV3000 takes the AMBE packets and decodes them to PCM (analog audio)
The analog audio packets are sent to the USRP channel driver .
The USRP channel driver just like the simple_usb channel driver sends 
audio to asterisk.

The "glue" that puts this together is software. This is not off the 
shelf software. Going forward, DSD will be gone. It works OK, but there 
is better. Next the sound FOB will go away.
This will be replaced by a purpose built digital audio modem. Start 
reading up on MMDVM from Jonathan G4KLX. Once we start using the MMDVM 
transmit will be possible.
As Mike mentioned somewhere, The is metadata that will come into play 
and will have to be dealt with.

The parts you want to start researching:
MMDVM
DSD
DV3000
USRP channel driver.

You can get your feet wet by setting up a receiver and DSD. With that 
you can listen to DMR, D-Star and P25 unencrypted signals.
This can be done under Linux or Windows.

73, Steve N4IRS


On 10/31/2015 06:46 AM, Robert Newberry wrote:
>
> Is there somewhere I can read more about this?
>
> I have a lot of questions.
>
> So when you say decoded audio you mean something like coming from a 
> hytera programmed to send that audio from its RJ45 on the back?
>
> Where does the dv3000 come into play?
>
> N1XBM
> Apparare Scientor
> Paratus Communicare
> Allstar Node # 27086, 41540, 41812, 42086
>
>
>
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-- 
"Anything is possible if you don't know what you are talking about."
1st Law of Logic

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