I was running the Amp Gain and Distortion Vs Amplitude test and was getting blank graphs unless I checked the gain tickbox for the tests. Then suddenly the plots are blank no matter what I do. Here is a sample of a plot from 30 minutes ago and one I just did without changing anything.
I restarted the computer and will reinstall software but figured it was worth an ask here.
(edit) Reinstalled the software and no change.
More info.
If I do a simple loop through everything works fine but when I insert the DUT I get the blank plot pane. It is the same on two different computers, will try a different DUT (amplifier) and see.
Hi @Dave, can you show the test setup screens you are using for the tests? When a mathematical result is a NaN (Not a Number, which can come, for example, dividing zero by zero), then the points won’t be displayed.
Also, I note that you are displaying Gain and THD at the same time, which comes from running two different tests but plotting them to the same graph. That’s a bit in uncharted waters, and by that I mean it might work, but there are time it might not work too.
If you run the gain test by itself, does that give you the plot you expect? And if you run the THD test by itself, does that give you the plot you expect?
More info.
If I do a simple loop through everything works fine but when I insert the DUT I get the blank plot pane. It is the same on two different computers.
At one point I had to check the plot gain to get any results and now when I do get plots even with the gain box unchecked it still plots gain. If I disconnect the DUT from one channel it works.
found a way to trick it…
here is the setting pane and it returns the blank When I enter a number in the Y1min the plots suddenly appear.
Hi @Dave, if you specify a Y1 Min Value that is greater than the Y1 Max value, then there’s not much to show. Can you make sure your Y1 Min is less than your Y1 Max?
The gap in the data is still confusing to me. From what you have written, in loopback there is no gap, but when you add in your DUT with about 17 dB of gain, the gap shows up is that correct?
The “blank” plot happened without me ever entering or changing numbers. I was able to trace it down to the right channel input causing it and as of late everything has been fine.
along these lines, I also find it odd that for anything with gain (+Vu), the plots only go to 0Vu and I have to manually increase the range to see the info.
It would be nice to auto-range the plots to show all of the plotted data and to remember the extents if manually changed and more data is added.
the ability to fix the ranges would also be a nice option. This is only for the automated tests that bring up a new plot window.
dave
