Noise spectral density measurement

Matt added the V/rtHz capability to the UI some time ago, possibly from my request. I just had the need to use it and ran into some confusion. I believe it will work the same in the later versions as well.
I have two ways to measure noise density, A wavetek and the QA401. (There are other ways but they are so arcane and involved as to not be worth the effort.
In any case I’m checking the accuracy of a Quan-Tech 420 noise generator which is calibrated volts per rt/Hz. Initially I was getting a 6 dB different between them. After much poking around the interwebs I saw a reference to “windows” and it occured to me to see if they affect the measurement and they do. It’s to be expected BUT the Wavetek has one fixed window so I was not thinking and I naievely expected QA to adjust for the different windows. No such luck at present. Still the rectangular window gives the correct levels (in dB, I would like a V/rtHz number relating to the cursor but I’m happy to have this). Both instruments are within a few percent so I can trust the readouts.

HI @1audio, I don’t think the QA401 software adjusts for window sizes, but the QA402 software does.

Thats a good improvement not that different windows when corrected should give different results. For vaidating noise sources per GR you need to do statistical density distribution. Now to figure out how to do that.