Re: [Discuss-gnuradio] DAB with GNU Radio

[Andreas Müller]

Hello Chris

> we would like to implement a DAB receiver with GNU radio. On the 
> hardware side we have a USRP with the TVRX daughterboard. 

Jens Elsner, who worked on DAB some time ago, found out that the TVRX
actually disturbs the OFDM signal very much, making it rather hard to
receive DAB, so I would strongly discourage its use (I'm not able to get
any information out of TVRX samples currently).

My current setup involves a spectrum analyzer to receive the signal, and
an external mixer+signal generator to convert from the IF of the SA down
to 10 MHz for the BasicRX. I have uploaded some of the samples to [1].


If you have a DAB station in the L-Band near you, you can also use the
DBSRX. (@Jens -> is it ok if I publish your mode 2 samples as well?).

> From some 
> older posts on this list, i learned that there are already some people 
> trying to do this.

I have implemented part of DAB for my current semester thesis. I have a
working physical layer (all OFDM stuff, all 4 DAB modes complete for
transmitting and receiving), and enough of the FIC (fast information
channel) to see the names of the radio stations (receiving+some blocks
for transmitting; all modes). To actually hear something, the MSC
(main service channel) would be needed (many blocks in the MSC already
exist, as they are needed for the FIC too, so it should not be that much
work).

> Is there any initial advice or pointers to existing implementations you 
> could give us? Do we need the checkout the svn version or even some 
> branch or is the 'latest stable' enough?
> 

I have uploaded my current code to [2]. It requires GNU Radio from the
trunk and some small patches (mainly for the peak detector). If you are
interested, I can also send you my mostly-finished semester thesis
off-list.

I hope to finish the FIC in the next week or so, but as my thesis is
over at the end of this week, I am not sure, when/if I'll get to the
MSC. The code for OFDM and FIC currently runs real-time on my four year
old ThinkPad (Pentium M 1.6 GHz).

Regards, Andreas

[1] http://people.ee.ethz.ch/~andrmuel/files/gnuradio/samples/
[2] http://people.ee.ethz.ch/~andrmuel/files/gnuradio/gr-dab.tgz

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