On 08/07/2014 03:32 PM, chaitanya wrote: > Hi Marcus > > Thanks for reply > >> Your GRCs don't work for me. With which version of GNU Radio were they > built? > one is version 3.6.5.1 and the other one is version 3.7.2.1. > I think the device addr in usrp sink and source should be changed.And also > the file path in file sink and source should be changed according to ur > system.
Ah, so you're using the old OFDM components, I guess. Not what I was assuming. What's your UHD version? >> Thinking about this, that was a bad question from my side. >> Since the ofdm_mod doesn't even *know* about the center frequency, the >> signal generated digitally is always the same, so you can only be >> looking at the rx side's abs(FFT). > > yeah,at rx side only > >> Would be nice if you had a description of what happens or a screenshot > uploaded somewhere! > > These are the screen shots of FFT at 2.45GHz and 2.455GHz center > frequencies. > 2_45GHz.png <http://gnuradio.4.n7.nabble.com/file/n49851/2_45GHz.png> > 2_455GHz.png <http://gnuradio.4.n7.nabble.com/file/n49851/2_455GHz.png> > > These are the screen shots of FFT at 2.452GHz and 2.454GHz center > frequencies. > > 2_452GHz.png <http://gnuradio.4.n7.nabble.com/file/n49851/2_452GHz.png> > 2_454GHz.png <http://gnuradio.4.n7.nabble.com/file/n49851/2_454GHz.png> Posting this earlier would have helped. Your rx spectrum is pretty screwed up at these frequencies. I can't say why, but I'd like to get the version issues sorted out first. Also, I recommend using the new OFDM subsystem. Refer to the manual for details. Cheers, Martin > > >> Ok, you're seeing frequency selective behaviour. This can happen for a >> myriad of reasons, among these interference and multipath propagation. >> You're excluding interference as a reason on an ISM band, so I presume >> you're working with a direct cable between tx and rx or in an anechoic >> chamber; thus multipath can't be the reason, either. > > No , I am not working with a cable between tx and rx or not in an anechoic > chamber.But I can say there is no interference (as on ISM band) because when > I run the benchmark_tx.py and benchmark_rx.py files ,then most of the > packets are being received (i.e, n_right value is near to n_rcvd ) even at > 2.452 and 2.454GHz center frequencies. > > chaitanya > > > > -- > View this message in context: > http://gnuradio.4.n7.nabble.com/OFDM-TRANSFER-and-RECEIVE-IN-GRC-tp49746p49851.html > Sent from the GnuRadio mailing list archive at Nabble.com. > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
