Peak-to-Peak vs Mean Voltage Measurement
Use the Mean setting.
The mid-point of the Peak-to-Peak can differ significantly from the mean if the signal is asymmetric (eg a pulse that only occurs occasionally).
Be aware that most oscilloscopes perform the average on the signal displayed on the screen - if there is not an integer number of full cycles the average may not be correct.
For example while displaying a sine wave and 1-1/2 cycles are displayed the average will consist of a full cycle (which will average to zero) together with one half cycle (which will have an non-zero average) so the displayed average will not be zero.
To avoid this error there are two options; either adjust the horizontal time base so that exactly one or two (or any integer number) of cycles are displayed.
Or use the &quot;Cycle Average&quot; that most scopes have. This will calculate the average for complete cycles and give the correct result (zero in this example).