The release hasn’t posted yet, but I wanted to share this short document about copying and embedding EMF files from the QA40x application to Word or PowerPoint or Adobe Illustrator, etc. This allows you to copy a graph in a vector format onto the clipboard. When pasted into an app such as PowerPoint, the vector format is preserved meaning the data never gets fuzzy regardless of resolution or zoom levels
In the attached PDF, zoom to the max and you’ll note the graph remains as clear as the text. And if you print to a high resolution device, such as a 600 or 1200 DPI, you’ll see it renders at the native resolution of the printer and looks great.
If you are writing technical reports and including screen shots, this will help the work look that much better. Note that the Visualizers don’t have this capability yet. But the main screen graph and the automated test graphs do. Just right click on the graph and select the “Copy to EMF”. You can also do “save image as” and then select an EMF file (that has been there since the beginning). But the clipboard should make this a lot more useful for technical writing.
Matt,
I am in the unfortunate position of having only a 401A, unable to buy anything new due to availability. I would really appreciate an update to the 401 software that incorporates new features to the extent possible… We had an exchange a year or so ago about problems with the 401 software. It doesnot work very well on a laptop with no middle mouse button for scrolling. It does not respond the the touch screen input. There was also the problem of the notch width excluding harmonics for lower scan frequencies to which you proposed some advanced options to allow setting up the width and limiting the number of harmonics.
Last time I tried the new software, it had the 401 device greyed out.
Yes, for sure agree on the QA401. The problem right now is that instead of an analyzer lasting five years in the market, the silicon shortage has pretty required a new analyzer (and other products) every year and the time required to do that is extraordinary. I think the QA452 with workarounds is just about ready, and then comes the QA480 and QA461. Sorry the news isn’t better there.
Hi @BKDad, the QA401 started shipping in 2015 and the last SW release was in December 2020. I’m pretty sure there won’t be any more features added to the QA401 software.
Hi @Bonzoro, the QA401 still works as well as it did when it was introduced into the market. I’d say if programmability with a language like Python or C# or Matlab was important to you, then seek out a QA402 instead. I’d say if performance (and programmability) was important, then seek out a QA403 instead. But the QA401 should still work fine for a majority of tasks.
I have spent a good deal of time trying to use the 401A. It works well for THD > .001% (-100dB) at frequencies of 1k and above. Signals up to 2V work well, and frequency response sweeps are useful and work well. It’s easy to use. Matt’s support here in the forum is first rate.
Those are the good points. Now for some of the limitations.
The input channels seem to have THD just under .001% - say around -102 dB. As I try to test circuits to below that level I see the same harmonic pattern that I see in the loop back measurement, perhaps just a couple of dB higher. Thus I conclude that it is mostly the input channel. The best THD measurement I have been able to get was around -110 dB after fiddling with the levels to find the sweet spot. Muting the right channel output reduces the distortion, indicating that the cross-talk between channels is an issue.
Using the attenuator adds in a lot of 60 Hz and harmonics.
Then there are all the problems with the software. On a laptop without a third mouse button, I have found it impossible to scroll/pan around the screen once I’ve zoomed in. When testing at lower frequencies, such as 100 Hz, THD is reported as much higher than THD+noise. Matt and I discussed this last year, and the problem seems to be the width of the notch, which can obliterate several of the lower harmonics. Trying to zoom in on the response of a notch to determine the exact bottom frequency is not possible. The marker is looking for peaks, and so the marker system in not useful.
Generally, I have better luck with the user interface on a regular computer. My lab makes that inconvenient, as my desktop is not very close to the lab bench.
The input channels seem to have THD just under .001% - say around -102 dB
I’ve pasted a link to the QA401 product sheet. Make sure you can replicate the measurements in there to verify your device THD is as expected.
On a laptop without a third mouse button, I have found it impossible to scroll/pan around the screen once I’ve zoomed in.
Check with your laptop vendor on how to emulate a middle mouse button on your laptop. Most all can do it as it’s such a common operation anymore. The default is usually press and hold control AND the left mouse button on the trackpad. And then you can pan around as needed. Usually you use the left and to do the CONTROL + left mouse button, and the finger of the right hand to pan around on the touch pad.
And to reset the zoom, just hit the X Linear or X Log button and it will reset all your zooms on the QA Analyzer software.
The marker is looking for peaks, and so the marker system in not useful.
Yes, a marker needs to know if you want it to find peaks or valleys. On the QA Analyzer software, you can only look for peaks. On the QA40x software, you can add a cursor and slide that to an arbitrary location and then make delta measurements for that. The QA401 software doesn’t have that ability (markers only, no cursors)
Thanks for the info. I got the scrolling to sort of work. I think I should just find room for a real mouse on the lab bench.
The software limitations are why I and others would like an update for the 401.
I measured the THD from the input as specified in the data sheet, and my unit meets or exceeds those specifications. The problem is that I am working at a minimum of 1.3Vrms input levels so I either have left the sweet spot behind or have to use the attenuator which puts the harmonics down amongst the noise. I guess I’ll have to try my own attenuator. The sweet spot for the 1664/1656/1612 seems to be about 4Vrms output according to the data sheets.
I dialed the output from the oscillator as low as it would go and get -102 dB THD. Turning on the generator degrades that to -96. The crosstalk is almost all 2nd harmonic, taking it from -112 to -96.
I’m not complaining. The 401 is much better than anything else at that price point. I would gladly buy a 403/4/5 or whatever you manage to get out the door next. You undoubtedly know that TI has a direct sales website. I have found parts there that are not available from the distributors. I guess you are looking for some specific USB to +/- 15 V switching supplies. Personally, I’d be happy with a unit that would require external supplies.
Hi @mhuth1776 , yes, understood and it is currently the plan, but I hope you can understand with every single product sold out due to silicon shortages, the first task at hand is to redesign products as needed to get them back in stock. And that is a fairly large task that is taking some time.
Take a look at page 16 in the OPA1664 spec. In there, TI is telling you the distortion from the opamp is too low to measure even on $30K analyzers, and as a result you need to build a circuit to “magnify” the distortion.
I think that in general, if a circuit with an opamp or two is properly designed and you are using a premium opamp, you probably won’t be able to measure the THD or THDN of the circuit even with a $30K analyzer. You can make sure you aren’t ruining the opamp’s performance. But the typical THD+N of the OPA1622 is -124 dB, and there’s not really anything available, even at $30K, that can measure that with sufficient margin. That’s why TI publishes the op-amp distortion “magnifier” in all their spec sheets.
