Products > Test Equipment
Siglent SDS1104X-E anomaly on what should be a simple task.
<< < (5/9) > >>
tautech:

--- Quote from: bdunham7 on February 06, 2021, 10:44:51 pm ---
--- Quote from: tautech on February 06, 2021, 10:34:39 pm ---With Measurements or Cursors.

--- End quote ---

Still not seeing that it is possible.  Let's try a simple example.  I have a triangle wave of about 5 Vrms riding on an approximately 10VDC signal.  I don't know either value exactly.  What I want to do is measure the voltage relative to ground of the signal at the lowest point of the triangle wave.  How can AC coupling manage that?

--- End quote ---
Simple examples displaying the usefulness of AC coupling.
Waveform details deliberately not stated as the displayed info is sufficient to understand what it is. DC coupling tells that story.
Channels 2 and 4 show the same waveform and the offset value when DC coupled shows how much the waveform is above 0V. Measurements deliberately omitted as we have graticules.


AC coupling removes that offset and allows us to examine parts of the waveform to the limits of the channel offset specification. Channel tabs and menus tell the story.  ;)
Any part of a waveform can certainly be measured with cursors.
bdunham7:
I'm listening, but not convinced yet.  That looks a bit messy and I think you may be overdriving your scope as well in that example, even with the AC coupling.  Offset range and amplifier dynamic range are different and you are driving it 190 divisions off the top of the screen.

Humor me--try the exact test signal I was using.  I used the SDG2042X, with 0-5V volt rectangular pulse of 100 milliseconds at 5 Hz on CHQ and a 100mV 1ms 100Hz rectangular pulse on CH2 and then combined them in the output menu.  I want to pretend that small pulse only exists on the trailing edge of the big one--the rest are just for comparison--and I'd like to see if you can use your technique to accurately measure and perhaps cleanly display that pulse as accurately as the Tek scope does in my last picture.
StillTrying:

--- Quote from: bdunham7 on February 07, 2021, 06:40:03 pm ---Offset range and amplifier dynamic range are different
--- End quote ---

Yep, everyone is confusing the Y offset voltage with the pk-pk dynamic range of the variable gain amp.

There's some triangular waveforms distorting because of the amount off screen waveform here.
https://www.eevblog.com/forum/testgear/siglent-sds1000x-series-oscilloscopes/msg1208426/#msg1208426
bdunham7:
The interesting thing--I see it mentioned in the other thread as well--is this is mostly a low-frequency phenomenon.  I say 'mostly' because it causes a residual offset at higher frequencies too.

I tried a different setup--a +/- 5 volt square wave with superimposed 10kHz 100mV pulses.  I set the channel to 200mV/div with a +5V offset so that the lower portion of the wave should be right on the center grid line.  Set it to 1 Hz, captured the trailing edge and then some of the flat section so that you can see that -5V section of the square wave does indeed eventually line up with the center grid.  But the trailing edge shows many milliseconds of recovery from the overdrive.  Then I increased the frequency to 1kHz, now  you can see the bottoms of that are relatively flat, but offset upwards by 200mV.  AC coupling made little difference.  At 200Hz, you see a bit of recovery 'bounce', looking sort of like the one Tautech posted.









py-bb:
You posted a link to this from one of my threads and I agree your situation is terrible, the pictures show a stark contrast.

What do you think of a Rigol DS1052E?

I'm after a digital one to capture things that don't repeat and I'm not asking for recommendations as such, I'm asking "is it afflicted by the same deal breaking problem?"


Or was yours somehow defective? The probes perhaps?


Thanks
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod