Help with TRBO decoding

[TrickySpot]

Anybody who's a whizz with Mototrbo want to help out somebody starting from scratch?

I gather from reading elsewhere the data is in binary format, which I can only guess must be serially transmitted. I've run a sample .wav file through matlab and got out the decimal values...taken decimal below 0 as a "1" and above as a "0", I believe the data is inverted. So I can see the patterns running through the data, but stuck at how many bits each frame is....can't seem to see any logic....and since there are two channels, I assume that one channels data is transmitted directly after the first, but that's a big assumption.

Help would be appreciated!

 

[TrickySpot]

Update, got the DMR tech notes for the frame construction.....deconstructing now in excel - once I get the sync bits done, should be easy enough to write a VB app the do basic decoding.

 

[TrickySpot]

Hi Guys, can anybody confirm that I understand correctly, for every 27.5 ms of audio, you need to pull 264 bits (132 symbols), so your waveform should have 264 peaks (either + or -)?? OR

Are you looking for 132 peaks of 2 bits each? Would make sense, as the Java code seems to look for sequences of 1 and 3's (I don't know Java, so can't decode the java code)

I'm getting about 180 bits out of every 30ms burst, think my reception is too poor, anybody have a nice clear recording of a DMR transmission?

Cheers,
Tricky

 

[TrickySpot]

Noooo....its FSK, not ASK......start again

 

[SCPD]

You will need DMRDecode and this web site ASCII, Hex, Unicode, Base64, Binary, Octal Converter

Start by capturing the data through DMRDecode into a log file. you will need a good capture of 3/4 Data binary for a clean msg!

Once you have your Binary 3/4 Data you will need to remove the first 8 bits and the last 8 bits of the binary data. open up the web site as above, copy and paste the remaining Binary bits into the "Decode Binary into ASCII" window, check the "Binary" check dot at the top, uncheck the "Space between bytes" box then click on the Decode Binary into ASCII button. job done :biggrin:

 

[rjschilder]

TrickySpot - any chance I can get a copy of those DMR tech notes? They may help on a project i'm working on.

Thanks!
-Ryan KC9GMY