QA40x Release 0.999

The release of 0.999 is located here.


This release adds the ability to add one or two cursors to the main display. The cursor control box is located beneath the Run/Stop control:


When you turn-on C1, you will add the first cursor to the display IF a trace is present.

The added cursor is show above, There are two elements to be aware of. First, is the “1” marker. This is the yellow box highlighted by label “A”. You can grab this box and move it left or right and place it as you see fit. The X,Y values associated with the cursor are shown in the legend highlighted by “B”.

The cursor can be off screen to facilitate measurements on very zoomed regions. If you need to bring it back to the visible part of the screen, just press the “Center” button.

Each cursor can be associated with the Left or Right display. You indicate what you want the cursor attached to using the Left or Right buttons in the cursor control box.

The cursor also works in the time domain display. Below the cursors are using to measure the time between zero crossings, and we can see the time and also 1/time in the legend.

Zoom Stack

If you zoom in on a trace using the mouse to drag a region, then you can “back out” of that zoom by pressing the back button on your mouse OR by pressing the arrow that shows up in the lower right corner of the graph display. As you press the button (mouse or on-screen back arrow), you’ll step back through all your different zooms until you are back home. The on-screen arrow makes it easy to back up on touch screens.

At any time, you can zoom to the full display extents by pressing either the “Time” or “Freq” button in the Display Options control block.

THD and THDN dB or PCT Preferences

You now have the ability to specify your THD and THDN default preferences. These are global settings and are located in the THD and THDN context menus (right click or click and hold on the THD measurement button to open THD context menu).


The 0.999 release is on Github. See the release notes at the link for other fixes and changes.

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I have noticed with 0.999 that the Y axis controls do not work any more, and this includes the Y preset buttons.

Yep, I just plugged the interface into a computer with 0.998 and the Y axis works fine. Upgraded to 0.999 and they don’t work.

Hi @Rammis, got it, thanks! There is a release 0.9991 today that will also have “peak” buttons so you can nudge a cursor to the nearby peak. Currently it’s too hard to move the cursor right to the tip of a peak by hand. I’ll make sure the bug you note is fixed too.

The new cursor feature is very slow even on a fast computer. It is very difficult to position a cursor at a particular frequency. it would be good if the cursors could be positioned with the left and right arrow keys.

Hi @Rammis, release 0.9991 is located here

Hi @Avo, in release 0.9991 there are independent peak buttons that will let you move a few samples to the nearest peak.


I’d not consider my machine that fast (~2 years old) but speed seems OK. Do you not see similar performance? Or are you using very large FFT sizes?

In release 0.9991 the Y presets are fixed but the Y Min / Max / Up / Down buttons still do not function.

BTW, it would be nice if the “Set Peak To 0” in the dBr settings had an option to “always do this” so that if I change levels, I don’t have to again manually set the peak back to 0.

The “Peak” feature seems to be responsive on my 3 year old computer.

I think the issue is for very large FFT sizes…checking on this. Noted on ymax/ymin. Also, changing FFT sizes has a regression and causes an exception.

0.9992 is up HERE and should fix the FFT change exception and YMAX/YMIN. Thanks for the very fast feedback.

I do not see the executable file there…

Hi @VAR, it went up a few hours after the posting. Thanks for pointing out.

Hi @Avo, if you enable cursors with 128K or larger FFT sizes, I think a pop-up for the user will be added stating that the data sets are too large for smooth cursor control.

Long term, the internal data sets and the displayed data sets need to be decoupled. That is, the calcs are all performed on the full data sets, but what is displayed is a heavily decimated version of the full data set. For example, if you have a 1M point FFT, but your display width is 1920 pixels, then your displayed data can be shrunk down by a factor of 500X while still showing all the peaks and valleys.

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Hi Matt, I have tried the cursor feature with 32k point FFT. The performance is good. With a 128k or 256k points FFT, the performance is not so good (I use Ryzen 5, 4500 system which should have enough perfomance for the QA402 software). There is no pop-up (or is this in a later release?).
With 0.9992, the other problems I have noted seem solved. Thank you to the QA team for having released this update so quickly.

Yeah! So good to have Cursors, particularly when doing an FR. My life got so much better. :smiley: :joy:
Of course, it would be nice to have a MIN as well as a PEAK, should you ever run out of things to do :smiley:

Hey @matt, would it be possible to upload a mono version of the newest release as well? :slight_smile:


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When appending additional traces to an Automated Test (frequency response using chirp in this case at least), as each new measurement is added to the original graph, the Y axis limits I set are ignored and the graph resets to its ‘default’ Y limits. I change them back to what I want, and they are again ignored when I add a new trace.