Products > Test Equipment
Sub: Rigol's DHO800 Oscilloscope (Gibbs Effect & Aliasing Misunderstanding)
Mechatrommer:
--- Quote from: ebastler on October 26, 2023, 08:14:12 pm ---Yes, a steep (higher order) analog, "physical" filter will give the same effect.
--- End quote ---
i noticed gibbs effect is worst in siglent at much lower sampling rate, but not at its max smapling rate. from here https://www.eevblog.com/forum/testgear/rigols-new-dho800-oscilloscope-unbox-teardown/msg5121846/#msg5121846
1GSps:
100MSps:
lowering sample rate should lower the cut off frequency, not creating more high frequency elements. even sampling below nyquist and straight plot point to point (no sinc interpolation) will not "fabricate" this artifact, if its a real physical filter that caused it, why implement a physical filter that causes artifact that is not seen in high end dso?
--- Quote from: 2N3055 on October 26, 2023, 08:31:21 pm ---Most modern scopes, especially higher BW ones will have that overshoot as a consequence of brickwall AA filter used.
--- End quote ---
see? i think my point will be side tracked again, i was talking about "non-causal" or "precursor" ringing... not overshoot not undershoot that we usually saw :palm: do you care to read my long post above? or at least look carefully at 1st picture attachment, that whats i'm talking about. here again...
ebastler:
--- Quote from: Mechatrommer on October 26, 2023, 08:33:55 pm ---i think my point will be side tracked again, i was talking about "non-causal" or "precursor" ringing... not overshoot :palm: do you care to read my long post above? or at least look carefully at 1st picture attachment, that whats i'm talking about.
--- End quote ---
Got your point now -- please see the "Edit" in my most recent post.
Maybe your original post was a bit too long for me, with too much text. Talk about a "brickwall"... ;)
Good night!
Edit: I Still stand by my earlier assessment,
--- Quote ---It is the real signal, as represented by all its harmonics that fall within the scope's Nyquist limit. Which, one could argue, is what you expect a DSO to show you.
--- End quote ---
But getting that "ideal" set of harmonics, without relative phase shifts, can't be done with an analog filter. Hence there must be digital filtering happening in the Siglent.
Martin72:
--- Quote from: Martin72 on October 25, 2023, 09:25:52 pm ---You have made me curious... ;)
You don't necessarily have to open it to find out what the quality is like.
Because in the end it's what comes out that matters....
I'm just thinking about a USB-C adapter on which you can make measurements.
--- End quote ---
I have now ordered USB-C breakout boards, once to look at the signal quality of the power supply and as a nice side effect, to check the accuracy of my USB-C powermeter. ;)
If someone should have opened the liteon power supply, how many wires come from the connection line ?
TimFox:
A lot of posts on this thread, include mention of Lenovo (supplied with my DHO914S) and LiteOn supplies.
Has anyone made a direct comparison between DHO800 or DHO900 performance with different power supplies, or, even better, between a supplied unit and a very clean non-switchmode lab supply?
Martin72:
No, but it´s a nice idea, will do it in the next days.
--- Quote ---DHO800 or DHO900 performance
--- End quote ---
What performance? Noise ?
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