RIGOL DM3068 - Manual (Page 144)

RIGOL Chapter 5 Measurement Tutorial
User’s Guide for DM3068 5-4
measure the DC and AC components of the signal using DCV and ACV
measurements, and then calculate the AC+DC true RMS value according to the
formula below. In order to obtain the best AC rejection, select 6.5 digits when
measuring DC voltage.
2 2
) (
DC AC RMS
DC AC
+ =
+