I´ve meant it in general, what we´ve noticed so far in this thread, what was solved from siglent, what´s still to do and so on...
Since today I have may a new one using current FW... (did not search on this lengthy thread)
1. running on 8 bit, vector display mode, on CH1 a digital square wave (0.3 low to 3V high) as 10MHz with 0.5ns rise/falling time
2. trigger about the half of the wave, show with cursor some 20% to 80% rise time as 0.5ns
3. add also color mode
4. all looks fine so far showing about 2 waves, with some small overshoots
than as soon I
5. enable Ch2, with or without 50E input, as nothing to display just enabled
6. On Ch1, the edges and overshoots gets modulated as like 50Hz, changed square from 10MHz to 49Mhz with same behavior
7. Change than from vector to pixel mode
8. all looks than fine .... No any more edge modulations visible
is this known?
IMHO it would be nice to have a thread moderated with current so easier to track as a bug tracking system
Btw, fast edges corners wobbling is not modulation... it is one form of aliasing and also possible "gibbs ears" (Gibbs phdenomenon) due to Sinc interpolation when not enough samples.
Long time ago I have somehow tried tell about Sequential Acquisition Random Interleaving (SARI) just my name for it for make clear it is not same as LeCroy RIS aka Random Interleaved Sampling mode, but somehow its small cousin.
But unfortunately it is only by my native Finnish language..
here (near end of page). The feature can be used in many situations as long as user know its features and limits in the particular oscilloscope user are using, in this case Siglent. But with it is also very easy to drop to trap. (one critical parameter is trigger engine used data stream and its sample interval what is not always same as ADC current displayed samplerate. )
Here signal is 45MHz square wave... and samplerate is 50MSa/s selected just for demonstration. Square wave freq 45MHz and sampled 50MSa/s. Where 3rd harmonic is 5.4*f
NyquistOf course depending signal ans scope and settings it may look much more nice and also without persistence, when wfm/s is enough.
btw, carefully look samplerate and displayed signal frequency.
One acquisition have only small amount of dots... display frame have many acquistions overlaid (as many acquistions as it have done in last TFT cycle). One single acquisition dots are marked red.
Also here is forum is some old treads about these things with some examples if I remember right.