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 -- View this message in context: http://www.nabble.com/Problem-with-symmetric-behavior-tp14642329p14642329.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
