SEFRAM 7314 Notice D'utilisation page 49

CMRR (Common Mode Rejection Ratio) :
The CMRR is the ability of a multimeter to reject the Common
Mode Voltage Vcm (The voltage present on both the COM and
VOLTAGE input terminal with respect to earth ground). The
Vcm normally comes from the electromagnetic interference of
high voltage power source line or generators.
NMRR (Normal Mode Rejection Ratio) :
The NMRR is the ability of a multimeter to reject the
Unwanted AC noise, V , in DC measurement.
NM
Burden Voltage :
Burden Voltage (V ) is voltage present on the CURRENT
BURDEN
input terminal and COM terminal of a multimeter. The presence
of the Burden Voltage on the current under test flows through
the impedance of the current sensing circuit of the multimeter .
The Burden Voltage will cause the measuring value to be less
than the actual value. For accurate measurements use the
approxi-mation described in the operation of Measuring
Current.
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