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Older DSOs tend to be worse, especially those with interleaved ADCs because of greater non-linearity in the digitizer. On these instruments the "wobulation" goes away when random equivalent sampling is used because the equivalent time sample rate is so much higher so there can be no aliasing. Modern instruments which lack equivalent time sampling can use averaging (HP/Agilent/Keysight recommended this in an application note), but I do not think this is as effective.
Siglent scopes have dot mode where they practically perform RIS (random interleaved sampling), although it is not marketed as such. If signal is triggering fast enough you get nice waveform reconstruction on repetitive waveforms, even when severely undersampled. So they don't market ETS or RIS but it still works as such.
That is effectively what HP/Agilent/Keysight recommended for DSOs which lack equivalent time sampling. The problem is that even in dot mode, (sin x)/x reconstruction must still be used to determine the trigger point, so the aliasing moves the trigger point around corrupting the result. Averaging helps, but it does not produce as accurate a result as equivalent time sampling.
As a practical matter, the difference should be irrelevant. In both cases the bandwidth of the instrument is insufficient to accurately represent the signal.
Display mode dots, interpolation x
( I have reduced memory for get enough low samplerate for demonstrate this)
In this image Zoom window
sample interval is 2 div (10ns)
Rise time here is <0.5*sample interval. I can not see big problems with trig position...
Of course can say that it is not accurately trig'd but... how big problems you see there... and this is
not ETS.
There on screen is
sequential
acquisitions
randomly
interleaved (overlaid)
However, this method has limitations, although it is useful in some situations. Most of the time, our real-time sample rate is sufficient because the full 2GSa/s can be kept up to 10ms/div (SDS2000X Plus)
But as can see trigger position is still ok even when in this case sample interval is 2 div in this Zoom window (4000x Zoom ). Digital trigger engine after ADC can still handle this quite well.