Martin, Thanks a ton for your help. Tuning the reciever via:
r = self.u.tune(0, self.subdev, target_freq) did the trick. Much appreciated! Rob Martin Dvh wrote: > > Robert Miller wrote: >> Hello, >> >> I created a flowgraph based upon the usrp_nbfm_ptt.py example. I am >> witnessing some weird, asymmetric behavior when running the graph. The >> code >> generates a tone from the user specified daughterboard and then plots the >> spectrum via an fft from another user specified daughterboard. I am >> using 2 >> RFX-1800 daughterboards with a single USRP to run the graph, however I >> imagine it should work the same for any RFX board. Here is the main >> issue: >> >> Everything works fine when using Side B as the transmitter and Side A as >> the >> Receiver. When running with Side A as the transmitter and Side B as the >> receiver, however, the fft display is really just noise (once in a while >> there exist some spectral lines at odd frequencies). As a note, I am >> fairly >> certain that the mux's are being set correctly and that the boards are >> tuning correctly. To verify that the issue is not the hardware, I am >> capable of running usrp_siggen.py and usrp_fft.py in both configurations >> successfully. (TXR A --> RXR B, TXR B --> RXR A). Also, I have done the >> tests in completely wired (with 60 dB of attenuation) and unwired >> environments, with both yielding the same results. Attached is the code >> that I am running, can anyone point out something silly that I am doing >> that >> is causing this problem? >> >> http://www.nabble.com/file/p14642329/DualChannel.py DualChannel.py >> >> As an added note, I am getting a segmentation fault when I close the >> graph >> by any means other than <Ctrl-C> from the command line. I don't think >> this >> is related to the above issue, and I don't get the seg fault when running >> the original usrp_nbfm_ptt.py code. >> >> Thanks! >> Rob >> > > Your problem is in the tuning I think: > > class receive_path(gr.hier_block): > .... > def set_freq(self, target_freq): > > r = self.u.tune(self.subdev._which, self.subdev, target_freq) # > <-- look here > > Which should be: > class receive_path(gr.hier_block): > .... > def set_freq(self, target_freq): > > r = self.u.tune(0, self.subdev, target_freq) # <-- look here > > The first parameter is the channel you are tuning, which is always channel > 0 if you only receive one stream. > It is NOT subdev._which, which indicates on which side the daughterboard > is. > > I hope this helps, > > Martin > > > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > -- View this message in context: http://www.nabble.com/Problem-with-symmetric-behavior-tp14642329p14681395.html Sent from the GnuRadio mailing list archive at Nabble.com. _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
