OSCILLOSCOPE DC Voltage Measurement Error

Thread Starter


Joined Sep 12, 2023
Hello everyone,

I have a R&S®RTM3000 scope. I can also provide a pdf with its specifications if needed.

My problem is:
I am supplying constant DC voltages to 4 channels of the scope. These are the voltages: 0.5, 1, 1.5, 2, 2.5, 3, 3,5 ,4 [V].
I am using "Mean Value" option in the scope to measure these voltages.
What I am experiencing is that I get different measurement results of the same supplied voltage on different channels.
I also noticed that the location of the signal on the scope's display also affects the results.
For example, the measurement results for a signal at the bottom of the screen may be slightly (or perhaps significantly) different from those for the same signal at the center or top of the screen.
I decided to record the differences between supplied and measured voltage for each channel for each state (bottom, center, top of the screen).
I calibrated both the scope and the probes before I started recording the differences, and I still got 15-20 mV difference. I have crossed probes and channels to see if there is a problem with the specific channel/probe, but it seems that the problem is not consistent, and it happens on different channels and probes.

I need to understand if these voltage offsets are acceptable and within specification range or is this a problem and if so, how can I fix it?

Here is the specification:
Attaching the page 5 from it that may be related to my problem.

Thanks for your time