Stereo Tool
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SDR-DAB and -FM with USRP, mmbTools and GNURadio on Linux
https://forums.stereotool.com/viewtopic.php?f=8&t=4859		 Page 1 of 1
Author:  radiofreak [ Thu Jun 20, 2013 7:26 pm ]
Post subject:  SDR-DAB and -FM with USRP, mmbTools and GNURadio on Linux
I've successfully tested the latest Linux-Version of ST on Ubuntu Studio 12.04 in combination with CRC-mmbTools and an Ettus USRP-B100-Box for a fully compliant DAB-Transmission. All runs nice and smooth on a (somewhat older) Lenovo ThinkPad-Notebook with a Core2Duo-CPU, even with the De-Clipper on!

There's a script running in the background that does the following signal pipe:
vlc (plays a wav-file and upsamples it to 48 kHz) -> stereo-tool (processing) -> toolame (dab-mp2-encoder) -> crc-dabmux (dab-muxing) -> crc-dabmod (dab-baseband-rendering) -> wapp (dab-baseband-player to the USRP)
It is also possible to get audio from JACK to ST via VLC and the jackaudio-plugin.

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Furthermore, I've built a GNURadio-application that allows to transmit MPX-WAV-Files (or stdin-datapipes) on FM directly via the USRP-B100. Unfortunately, it doesn't work with ST directly at the moment, because sampling rate input for stdin can be only 128 or 256 kHz (yet), and ST doesn't put out an mpx-stream with this sample rates. For first tests, I upsampled the MPX-recording of the Omnia 9 from the Processing Freakday to 256 kHz, and got it to work. Stereo, RDS - everything on the air with a tiny little box!

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Author:  Bojcha [ Thu Jun 20, 2013 8:25 pm ]
Post subject:  Re: SDR-DAB and -FM with USRP, mmbTools and GNURadio on Linu
Nice :)
Author:  hvz [ Thu Jun 20, 2013 11:06 pm ]
Post subject:  Re: SDR-DAB and -FM with USRP, mmbTools and GNURadio on Linu
Cool :)

I'm working on adding Jack support to the Linux version of Stereo Tool (that would in turn also enable MPX output etc), I hope it will be in the next beta version!

(Do you by any chance have some experience with Jack? I'm running into a weird issue: If I open the Jack connection from my main() function it works, but if I do the same from the thread that handles the processing it hangs on the jack_activate() call. If it cannot be used from within a thread (which seems very strange) I can make something that does it in the main() function but it would be annoying and unnecessarily complicated code.)
Author:  radiofreak [ Fri Jun 21, 2013 12:48 am ]
Post subject:  Re: SDR-DAB and -FM with USRP, mmbTools and GNURadio on Linu
Update!

Seems that the output-samplerate from ST is equal to the input-samplerate, so I simply piped VLC in front of ST for resampling the input-wave from 44,1 kHz to 128 kHz. Yes, it works, but ST then generates the pilot around 57 kHz?! So it's only usable in mono at the moment. And the CPU-load is immense, cause there's too much resampling in the signal-path.

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Quote:
I'm working on adding Jack support to the Linux version of Stereo Tool (that would in turn also enable MPX output etc), I hope it will be in the next beta version!
Hope this will fix all the issues :)
Quote:
Do you by any chance have some experience with Jack?
Sorry, unfortunately no. I'm very new to all the Linux-stuff...
Author:  hvz [ Fri Jun 21, 2013 1:18 pm ]
Post subject:  Re: SDR-DAB and -FM with USRP, mmbTools and GNURadio on Linu
The command line (and Linux) versions currently expect 44.1 kHz input, so that would indeed not work. And it doesn't resample, it just thinks it gets 3 times as much data... So yes, the CPU load would indeed be immense :)
Author:  radiofreak [ Fri Jun 21, 2013 6:12 pm ]
Post subject:  Re: SDR-DAB and -FM with USRP, mmbTools and GNURadio on Linu
Quote:
And it doesn't resample, it just thinks it gets 3 times as much data...
Okay, that indeed explains the ultra-high CPU-load when feeding it with 128 kHz :mrgreen:

Looking forward to the new Linux-Version with JACK- and MPX-functionality :)
Author:  veso266 [ Thu Nov 20, 2014 9:49 am ]
Post subject:  Re: SDR-DAB and -FM with USRP, mmbTools and GNURadio on Linu
could you please send the GNU Radio flowgraph and stereo tool setting file?

Best Regards
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