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Test conditions are two posts before in post #1743.

Effective bits:

My comparison of MSO5000 to SDS2000X+

I'm sorry but I dare to question @Howardlong's findings on the MSO5000 rms noise and thus the calculated equivalent resolution.

Just compare the peak-to-peak with rms noise figures at 500mV/div setting:

Vpp - 44.5mV

Vrms - 44.2mV

These two numbers are more or less identical which is mathematically impossible in case of an observation of AC signals. Vrms cannot be higher than Vp = 1/2 Vpp, which is the case if the signal has true square shape. And noise doesn't look that much like a square wave... On average, the crest factor for white noise can be assumed to be in the ballpark of 4, thus Vrms should be closse to 1/8 Vpp which matches the figures of the "big" Keysight and the TEK surprisingly well.

To explain the measured figures, I state that all those numbers that deviated considerably from the 1/8 relation had some amount of DC offset superimposed. This is easily overlooked since the zero marker is such a tiny pip at the left border of the screen... The better method of evaluating the AC component of Vrms using internal measurements is just taking the standard deviation of Vpp. This eliminates the average (DC offset) by summing up geometrically the difference of the individual measurements minus the average, e voila -- AC RMS

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The resulting equivalent resolution figures for some of the scopes will turn out much better if this calculation is done properly, but this wouldn't change the impression the reader now already memorized that the MSO5000 has got a front-end that's noisy like the Niagara falls... The apparent noise definitely differs, and Rigol for sure is among the noisier "party", but it's definitely not as bad as Howard evaluated in his table. Much of the apparent noise is also contributed to the way the traces are visualized, and Rigol's display engine traditionally emphasizes the extremal values and thus makes their scopes appear more noisy.

I'm not a Rigol or Siglent fanboy - I own gear of both companies and also had some "buyer's remorse" with both, but I think when publishing a comparison like this, we should at least make sure that the figures make sense from a mathematical point of view...