"Mirror QA401 Output" option level issue

[matt]

Looking at this more, I think there are a few things going on here:

1. When you enable Mirroring and press run for the first time, the level hasn’t yet been set. If you then increase amplitude by one step and then reduce it by one step, the correct value is written. This happens anytime you change the level using the dlg box. (eg control click on Gen1). So, the bug to be fixed here is to ensure the updated level is set for the PC in all the code paths.

2. For the automated test, the non-zero offset is one issue, but I think the issue identified in 1) is also coming into play

3. I don’t like that the frequency rounding isn’t happening for remotely generated PC tones. That is also an issue that was touched on in this thread:

QA401 Low Frequency Measurements

A customer writes with an issue related to amplitude errors they are seeing on frequency sweeps below 100 Hz. These can manifest as wildly wrong gain values. These are most often related to FFT size and/or window choice in some way. But a change will be made in 1.830 to help with the issue too. The “AMP Frequency Response” plug-in was used to plot the gain of the QA401 in loopback mode, from 2 Hz to 100 Hz, log step, at 5 points per octave (this was at 48K sample rate with Hann windowing). Thes…

I’ll try to get a release addressing the 3 items above turned around in the next few days.

Thanks for reporting, Matt