On Tue, Feb 9, 2010 at 9:04 PM, bin zan <[email protected]> wrote: > Hi, > > 1.Any one can tell me in gnuradio OFDM, after ofdm_sync block, what are the > data looks like?
The output of this block is a "voltage" level used to control and NCO as well as a timing signal. The NCO control signal is a stream of floats that is proportional to the frequency offset of the subcarriers. The timing signal is a stream of characters where a 1 indicates a preamble has been found at this sample position. > 2. Does the output go through FFT operation already? > If not, when does the FFT actually actually come ? Does it after the > ofdm_sampler block? > If yes, how can I actually get these data? And, how can I match the data to > the sub-carriers. > > Thanks, > Bin Yes, the FFT is done right after the ofdm_sampler. If you use --log when running the benchmark_ofdm.py script, you will get a bunch of data files, including ofdm_receiver-fft_out_c.dat, which is the data you are asking for. You can view it (if you have scipy and matplotlib installed) with gr_plot_ofdm.py. In the current git master, though, there's a small bug in this script because we changed the names of one of the output files. Just edit the script to use the right name (look at the error message and it should be obvious). This will show you a lot of what you are probably looking for. Tom _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
