When you say sample the channel - are you trying to look at the I&Q samples coming right out of the USRP2? In which case, the easiest way to start would be to use the usrp2_rx_cfile.py script, then you can load the file into Matlab/Octave/etc. to take a look at. If you want to record samples coming out of one of a block in the flowgraph (e.g. in the 802.11b scripts) - you can modify the flowgraph to connect up a file_sink at each point you want to record data from. Doug
On Tue, Sep 15, 2009 at 9:41 PM, Miklos Christine <[email protected]> wrote: > Hello, > > I'm trying to sample the 802.11b wireless channels but the USRP2. I'm > currently using revision 10689 of Gnuradio. > I've added code to bbn_80211b_rx.py to connect the gr_probe_signal_f() to > the top block. > To sample the channel, I use gr.probe_signal_f(). > Here's the code to connect the block: > > self.connect(self.u, self.conv_c2f, self.probe2) > > Then I use the gr.probe_signal_f().level() to retrieve the signal in a loop. > > data_file = open('data.txt', 'w') > T1 = time.asctime() > > while cs_samples < 1000000: > CST = self.tb.probe_channel() > data_file.write(str(CST) + '\n') > cs_samples += 1 > > data_file.close() > T2 = time.asctime() > > def probe_channel(self): > """ > """ > > return self.probe2.level() > > I was wondering if this is the fastest way to sample the channel from > python. When I compute how long this process takes, it appears that I can > get a sample every 8-9 microseconds, which seems a lot slower than what the > USRP2 is built to do. Am I sampling the channel in an incorrect way? > I'm running this on a machine with a Intel Quad Q9650 @ 3GHz. > > Thanks, > Miklos Christine > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > -- Doug Geiger [email protected] _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
