QA403 384Khz sampling rate

Hi @Matt. I wanted to know if there are any plans to enable 384 Khz sampling rate for QA403. Thank you

Hi @Claudio, I think the ADC side works at 384, but the DAC side does not due to the timing margin being too tight across the isolation buffer. Currently, I think the DAC sprays out gibberish, but that probably should be replaced with all zeros. On the QA403, can you select the 384K rate?

Hi @Matt. On my QA403 the 384 KHz sampling rate appears to be disabled, or I don’t know how to enable it. It would be a good thing if it were enabled on the ADC side and then you could use the ADC side at this sample rate. If there is a way to enable it that I don’t know, can you show me how to do it? Thank you

Hi @Claudio, I just checked and it’s not currently enabled. What we will add is a command line switch to enable 384K on the ADC only, and then the button will get enabled. And if people are finding it useful and reliable, we’ll go in and do the work to disable generation at 384K sample rate. But for now, if you have generation enabled in 384K, gibberish will come out of the DACs.

Hi @Matt. Thank you and I am very much looking forward to the enabling of 384 KHz sampling for the ADC. It is very important for me to be able to use the ADC at this sampling rate. Eventually I will use an external generator to overcome the DAC problem.

Hi @Matt. Is there any news about enabling the 384 KHz sampling rate? Thanks

Hi @Claudio, it will be in the next release, but that is probably a few weeks out at this point. Thanks, Matt

Hi @Matt. Very good. Thank you

@matt Is this still in development or is it clear by now that it can’t be implemented? E.g. for measuring input transformers that usually ring around or beyond 100k it would be nice to have.

Hi @THDaniel, it might be doable if users were able to tweak timing options on the command line. But that’s a bit too much for most. I think you can specify -384k on the command line and get the ADC side to run at 384k. The DAC output will be garbage, so don’t have anything hooked up to the analyzer output.

Hi!
I just got my new QA403. I’m trying to get up to speed on how to use this up to 384kSps.

What is the magic command line syntax that enables the 384kSps ADC’s? That seems to have been left out of this discussion. And which command line option are we talking about? Is this a windows DOS command line, linux command line, HRL command, etc? I’m a little lost.

I’m still trying to figure out how to use the http://localhost:9402 syntax for issuing get, put commands etc. For example, I just tried http://localhost:9402/status/version, but I get an exception when I try to do that.
Thanks,
Nathan

FYI … I figured out the syntax to make the QA403 work at Fs = 384kSps. The windows command line syntax, is “QA40x.exe -384k”. Like this …
CommandLineOption

Hi @nathanbaltz, yes correct. Just be aware that the DAC won’t work at 384, only the ADC.

I would like to try and take noise measurements above 90KHz and am struggling to enable this. This 386K button has been dangled out here as a carrot for years now. Can you at least provide some explicit instructions (for those of us that don’t use command lines daily) for enabling it? I’ve been farting around with this for a half hour now trying to enable this. After muddling around trying to even get to this directory, I entered this into the windows command line and got “access denied”.

“C:\Program Files (x86)>\QuantAsylum\QA40x>QA40x.exe-384k
Access is denied.”

Hi @RobbN. I created a very simple batch file and activate the 384k mode by launching it. I am testing it right now and everything is working smoothly. I am attaching a scrennshot of the file.


Create it with text editor like Notepad, but save it with extension .bat, no with extension .txt. Once saved as a batch, simply double-click on the file to launch QA40x in 384k mode

I Just created a copy of the desktop QA403 icon, named it as you like, then right click on it and PROPERTIES; in the DESTINATION just add -384k after the ending " (be sure to give a space). Job done.

Yes, I think @clane has the right approach. Duplicate the icon and then depending on what you need, you can have an icon for other options like console, 384k, logging, etc.

And then pin each to the start menu, and when you type qa40x, it finds them all

Thanks much for the help, Guys. It was still a bit confusing. For other boneheads like me (at least with Windows 11):

There is no “DESTINATION” under properties for the link. It is labeled “Taget” under the “Shortcut” tab. I also missed Clane’s note about putting it after the quotation mark. If you put the " -384k inside of the quotation marks (immediately after the program file name) it give you an error.

Now though, every time I launch to program, with or without extension, and regardless of using the shortcut icons, or the Widows launch button, I always get a user access control message making me agree to make changes to the program. Is this normal?

Here’s how it looks like:

Thank you, Clane. It does look different on mine, as described–Windows 11 USA/English distribution.

Have you (or anybody) used this technique and now have to agree to app changes at every launch? This is true even if I’m consecutively launching the standard version?