Common-Mode Rejection - Tektronix P5210 Instructions Manual

NOTE. Common-mode voltage greater than 2,200 V
distort the output signal, but the probe will not indicate an overrange
condition.

Common-Mode Rejection

The common-mode rejection ratio (CMRR) is the specified ability of
P5210 High Voltage Differential Probe to reject signals that are
common to both inputs. More precisely, CMRR is the ratio of the
differential gain to the common-mode gain. The higher the ratio, the
greater the ability of probe to reject common-mode signals. For
detailed specifications, see pages 21 and 24.
Common mode rejection decreases as the input frequency increases.
Figure 4 on page 26 is a plot of typical CMRR of the probe versus
input frequency. For example, if you apply a 60 Hz line voltage of
500 V to both input leads of the probe, the probe rejects the signal
P-P
by 80 dB (typical) and the signal appears as only a 50 mV
on the oscilloscope screen.
P5210 Instructions
Operating Basics
CAT II can
RMS
signal
P-P
15