I was making an amplifier circuit, and found it was oscillating at really low freq, down around 1Hz. My hacked sdg2042x was set to 800kHz. And then after playing around I noticed it is the AWG all on it's own doing it. I never noticed this before.
Looking at the AWG alone with 1Vpp
100kHz 1.24Vpp and 0.42Vrms ~0.05Hz (w/ scope on ~5sec/div)
1MHz about the same voltage, about 0.5Hz
Zooming in on the 1MHz signal, I see it's 1.25Vpp, 0.44Vrms
So without trying my analog scope, am I just seeing a frame rate effect, like when a spinning tire looks stopped ?? Or is it actually a real oscillation, maybe from ADC/DAC low freq noise??
I swear I never noticed it like this before, when using the AWG and the same scope together.
Your 1st image.
![](https://www.eevblog.com/forum/testgear/low-freq-noise-from-siglent-awg-or-just-scope/?action=dlattach;attach=1308776;image)
Have you ever noticed that producing some types of humor is not quite easy.
(I can not believe you do not know basic fundamentals, so I first reaction is: this is some kind of humor)
Also I can try humor. Problem is between chair and oscilloscope.
Playing like kid, independent of true age, without full understanding is, of course, a fun pastime.
But seriously. I'll give you a hint. The AD converter can also be used for frequency conversions. Sure, I could say more clearly, but then you wouldn’t start learning the basics of a digital oscilloscope.
But then if this is real seriously made msg...
Look your first image right top corner two numbers... 99.9999kHz and Sa 50kSa/s
Your signal is seriously undersampled. fNyquist with 50kSa/s is 25kHz and you try look 100kHz signal...
welcome to world of digital oscilloscopes. You are not first one.
![Smiley :)](https://www.eevblog.com/forum/Smileys/default/xsmiley.gif.pagespeed.ic.R8GFI-pF6f.png)