Thanks a lot. I found the problem. I should have used 'int16' instead of 'int' nor 'float'. I think I have better spectrum shape for 20Mhz signal using UHD compared to gnuradio usrp2_rx_cfile.py.
But I found high frequency portion is somewhat suppressed than the original samples transmitted. One question is that whether it is possible to demodulate 20Mhz signal using Gnuradio. I think many are trying to demodulate 802.11 packets, but still cannot found any one succeeded. The maximum sampling that Gnuradio can provide rate is 25Mhz with decimation 4. But I am curious about whether it is possible to demodulate the 20Mhz signal without 2x or 4x oversampling. On Thu, Jan 13, 2011 at 12:31 AM, Josh Blum <j...@joshknows.com> wrote: > > > I am trying to use "rx_samples_to_file.cpp" in UHD to save samples > received. > > UHD seems save samples in complex integer format in c++. > > yes, COMPLEX_INT16 > > > However, it is not possible to read that format from Matlab. > > I'm not a huge matlab fan, but I am sure that it can read integers from > a file. http://tinyurl.com/6kyxdk4 > > > I have checked the Matlab utilities in Gnuradio, but they were not > useful. > > Its looks like you are not very familiar with matlab, so I suggest (out > of my person preference) that you take this time to learn python+scipy > http://www.scipy.org/ For one, its free. And I have always found myself > more productive with python, and I have found the plotting widgets and > mathematics that come with scipy give me everything I need. > > > Is that any simpler way to change the formats of the saving file so that > > Matlab can easily read? > > > > You can change the example easily to write binary floats. And with a > tiny bit more effort and a for loop you can write a text formatted file > as well. > > > Another question is that why the saved samples are integer format? not > > float? > > To save disk space and IO overhead for large captures or high data > rates. You will appreciate this if you change the example to output a > text format. > > Good luck, > -Josh > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > -- *From: Sangho Oh * *Voice mail: (609) 759-1552*
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