Re: [Discuss-gnuradio] DAB with GNU Radio
Christoph Fischer wrote: Hello Andreas, thank you for your very interesting reply. 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). That is bad news... So perhaps at first we should do some analysis if DAB is really impossible with the TVRX or if we only have severe degradation of SNR. We have a DAB transmitter just some km away from the university so perhaps it could somehow work at least for this one... Does anyone already have some data about the phase stability of the TVRX? Unfortunately the L-Band is no option here. You could try undersampling with basicRX. Frequency stability wouldn't be an issue. But the sensitivity is very very low and you get interference from all bands above 32 Mhz folded over each other. This could be improved by using a bandfilter and an amplifier in front of the basicRX. Just use a bandfilter which only passes the part of band III which you are interested in. The bandfilter should have a bandwidth of 30 Mhz or less. For example 170 - 200 Mhz. For amplification best would be a dedicated amplifier for this freq-band with 20 to 50 dB gain. But to keep things simple you could use an off-the-shelf amplifier for TV-signals which have usually 10 to 15 dB gain. As an antenna you could use a home-made vertical dipole or J-antenna for exactly the right freq. This also improves selectivity. greetings, Martin 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. Thank you very much for all that. We also would be very interested in your thesis. Regards, Chris ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] DAB with GNU Radio
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 signature.asc Description: OpenPGP digital signature ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] DAB with GNU Radio
Hi Andreas, I am also interested in your work. Would you be so kind of sending me your thesis when it is finished? Thanks a lot! Best regards, Carles Fernández. On Tue, Jun 10, 2008 at 4:01 PM, Andreas Müller [EMAIL PROTECTED] wrote: 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/http://people.ee.ethz.ch/%7Eandrmuel/files/gnuradio/samples/ [2] http://people.ee.ethz.ch/~andrmuel/files/gnuradio/gr-dab.tgzhttp://people.ee.ethz.ch/%7Eandrmuel/files/gnuradio/gr-dab.tgz ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] DAB with GNU Radio
Hello Andreas, thank you for your very interesting reply. 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). That is bad news... So perhaps at first we should do some analysis if DAB is really impossible with the TVRX or if we only have severe degradation of SNR. We have a DAB transmitter just some km away from the university so perhaps it could somehow work at least for this one... Does anyone already have some data about the phase stability of the TVRX? Unfortunately the L-Band is no option here. 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. Thank you very much for all that. We also would be very interested in your thesis. Regards, Chris begin:vcard fn:Christoph Fischer n:Fischer;Christoph email;internet:[EMAIL PROTECTED] tel;home:07311761080 tel;cell:01728889339 x-mozilla-html:FALSE version:2.1 end:vcard ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] DAB with GNU Radio
Hello everybody, we would like to implement a DAB receiver with GNU radio. On the hardware side we have a USRP with the TVRX daughterboard. From some older posts on this list, i learned that there are already some people trying to do this. 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? Any help is very appreciated! Thanks in advance, Chris begin:vcard fn:Christoph Fischer n:Fischer;Christoph email;internet:[EMAIL PROTECTED] tel;home:07311761080 tel;cell:01728889339 x-mozilla-html:FALSE version:2.1 end:vcard ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
