[dsg-hdice] fsNMR test results

[Tyler Lemon]

Hi Xiangdong,

I looked at the fsNMR program and found a few bugs that I have now fixed:

  *   Auto-adjustment of lock-in amplifier gain was incorrectly using X measurement rather than amplitude
     *   This is probably why in all the plots with the odd stair-step appearance, the X data was the only one that looked okay.
     *   I ran a test with the same frequency range (40 MHz - 45 MHz) as in your last results document but with only 200 steps (to get the program to run faster) and everything looked okay; no stair-step jumps.
  *   Program had a subVI that was settings it's attenuation to -63 dB after a cycle, but the program never reset the attenuation to the user's set value.
     *   The setting to -63 dB explains why data was so small for subsequent cycles.
     *   This incorrect behavior has been corrected and the signals look very similar between cycles.
  *   Found that if background subtract was not used, program was still subtracting 1 from all data
     *   This caused all data to be offset by ~1 and in turn caused data to look odd/not expected when background scaling was used.
     *   After finding and fixing this, when background subtraction and scaling was then used, the results were all centered somewhat around zero.

With these fixes, the issues you noted in your last results PDF seem to be resolved.

Right now, I'm in the process of running a test with the same settings as in your PDF (40 MHz - 45 MHz, 2500 steps), but with only 10 cycles. As of this email, the program is on cycle 5 of 10 with no background subtraction/scaling. So far, everything looks good. Once that is complete, I'll use the results as the background for a second test. I expect these tests to run take the rest of the afternoon and maybe into the evening.

I will also be working on a short procedure on how to run the fsNMR program in various modes and will send that when it's done.

Best regards,
Tyler

________________________________
From: dsg-hdice <dsg-hdice-bounces at jlab.org> on behalf of Tyler Lemon <tlemon at jlab.org>
Sent: Monday, June 22, 2020 5:16 PM
To: Xiangdong Wei <xwei at jlab.org>; dsg-hdice at jlab.org <dsg-hdice at jlab.org>
Subject: Re: [dsg-hdice] fsNMR test results

Hello,

Attached is the document Xiangdong sent that I forgot to attach to my previous email.

Tyler
________________________________
From: Xiangdong Wei <xwei at jlab.org>
Sent: Monday, June 22, 2020 4:55 PM
To: Tyler Lemon <tlemon at jlab.org>
Subject: fsNMR test results

Hi Tyler,

The attached pdf file contain a preliminary test results of stage 1 and stage 2 fsNMR VIs. Please take a look.

I am not available for meetings on Thursday and Friday, but I can still reading email.

Thanks,

Xiangdong
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.jlab.org/pipermail/dsg-hdice/attachments/20200623/b9523d56/attachment-0002.html>