[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Discuss-gnuradio] Problem with symmetric behavior
From: |
Robert Miller |
Subject: |
[Discuss-gnuradio] Problem with symmetric behavior |
Date: |
Sat, 5 Jan 2008 18:09:50 -0800 (PST) |
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] Problem with symmetric behavior,
Robert Miller <=