kind of results

[aminichangeez]

Hello

Regarding the presentation named "tetra-toolkit", I would appreciate it if you please answer the following questions:

1. Why the Frequency (Hz) is set to 100M? Is not it over 300M?
2. What (kind of) results should I expect? A related figure of my desktop demonstration is attached

Thank you in advance

[Tim---]

Hi !

The 100 MHz is a placeholder for the target frequency. You must replace it with the frequency of the Tetra channel you want to listen.
Once you do that, you can use the different graphs to adjust the fine freq and gain, and make sure you have a clean signal. If you did everything correctly, your constellation view should show a QPSK constellation, with 4 distinct clusters.

Now the decoded bits are sent to the output of the "Tetra Demod" block. In the demo, this block is plugged to a "UDP Sink". So the bits are sent to localhost:1234.
Now you need to feed them to a program that actually decodes the bits, such as osmo-tetra.

I think in the end, you can decode the bits live with something like:

socat UDP-LISTEN:1234,fork,reuseaddr - | tetra-rx /dev/stdin

I hope this helps !

[aminichangeez]

Hello again
I followed your instructions and actually saw the QPSK constellation. However, I still need more help concerning the parsing (feeding them to a program that decodes the bits). Would you please guide me more on what I should do?
Best regards

[Tim---]

I added more details on the README, and updated it a bit.
This is a bit succint, but it should hopefully help you get started on how to use osmo-tetra.
Hopefully you should end up with a working Wireshark showing you the Tetra packets after that :).

[aminichangeez]

Hello,
Thank you for the new "README".

Is it possible to interpret the data offline? In other words, is it workable to use "File Sink" instead of "UDP Sink", and then input the results to the interpreter?

Best wishes