NOISE NOISE NOISE
The noise THHNew propose in his vagueness is indeed noise.
Electrical noise?? Audible noise?
Unless defined and accounted for
noise is just typical THHnew noise and blather
RB: this is a very strange approach - that if you cannot exactly understand what causes noise, then it does not exist?
I don't want to seem difficult about this - the noise here is quite interesting and perhaps someone (maybe ascoli, who is good at that sort of thing) can think of a source that fits it well. Probably the best preparatory work would be to look at approx 500s segments of time in this waveform and work out the noise by regression fitting a line to (only) the segment data and then taking mean square error as a noise amplitude measurement. In addition one could look at the noise statistics of how it deviates from the fitted (linear) curve. Note that the gradient discontinuity when the power is switched off cannot be fitted by a linear curve so should be an end-point, not in the middle of one of these segments. Having this noise amplitude measure throughout the curve we could look at how the amplitude varies with other parameters. I don't guarantee this would lead to any gems of extra info, but you never know.
A job for RB?