Running TX and RX simultaneously from CLI
Posted: Wed Sep 25, 2013 3:41 pm
I've been encountering some strange behavior when trying to simultaneously input a signal into TX and measure that signal from RX (with a cable connecting the tx port to the rx port) using the CLI. I'm running on Windows 7, and while CLI won't let me tx and rx simultaneously from a single command prompt, if I open two command prompt windows and use one to start/stop tx and the other to start/stop rx, then CLI doesn't complain. But the data I get from rx looks very unlike what I send into tx. For example, when I send a constant value (I=1024, Q=0) into tx, I see the following: plots
Here's a zoomed-in view of one of the large-magnitude portions: Next, I tried sending in a sine wave. When I send a sine wave into rx from a signal generator, I see a nice clean sine wave. But when I send it in from tx, I get: which looks similar to the case for constant input.
I checked my rx and tx gain settings, and I believe that I should be able to see some amount of the tx signal. Has anyone else attempted using tx and rx simultaneously from CLI? I'm not sure what could be causing this choppy behavior, since the conditions are the same over the whole data-taking time (eg no stopping/starting or changing settings). Does sending and receiving at the same time cause problems with PC loading or with USB? My eventual goal is to use the bladeRF as a network analyzer; has anyone else had success using it for that purpose?
Top left is I vs t, bottom left is Q vs t, and right is I vs Q.Here's a zoomed-in view of one of the large-magnitude portions: Next, I tried sending in a sine wave. When I send a sine wave into rx from a signal generator, I see a nice clean sine wave. But when I send it in from tx, I get: which looks similar to the case for constant input.
I checked my rx and tx gain settings, and I believe that I should be able to see some amount of the tx signal. Has anyone else attempted using tx and rx simultaneously from CLI? I'm not sure what could be causing this choppy behavior, since the conditions are the same over the whole data-taking time (eg no stopping/starting or changing settings). Does sending and receiving at the same time cause problems with PC loading or with USB? My eventual goal is to use the bladeRF as a network analyzer; has anyone else had success using it for that purpose?