That's great... but what do you see when you actually use _the same settings_ as the OP?
An interesting point, because his screenshots look better than mine (the noise has about the same amplitude, but it doesn't look as periodic) - mine had looked about the same on almost all the settings I tried, but I hadn't tried that particular configuration, so I did, and mine looked better too.
After a bit of experimenting, I realized I completely overlooked something - whether or not I was looking at an intensity-graded combination of multiple acquisitions. Single-shot capture attached - it doesn't look periodic that way. The 'wobbles' in the signal have a
similar spacing by appearance, but if you actually try to line up cursors with them, they're totally different frequencies.
The periodicity only becomes apparent when multiple acquisitions are involved. Second screenshot is the same exact thing, but a screen-freeze of a continuous capture instead of single-shot.
Iiiiinteresting. Something to do with the timing when overlaying multiple acquisitions?