Greenlee GT-540 Instruction Manual page 18

Specifications (cont'd)
* Noise rejection is the ability to reject unwanted signals, or noise.
• Normal mode voltages are AC signals that can cause inaccurate
DC measurements. NMRR (Normal Mode Rejection Ratio) is a
measure of the ability to filter out these signals.
• Common mode voltages are signals present at the COM and +
input terminals, with respect to ground, that can cause digit rattle
or offset in voltage measurements. CMRR (Common Mode
Rejection Ratio) is a measure of the ability to filter out these
signals.
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