Noise present equally on two conductors with respect to some reference point; often used specifically to refer to noise present on both the hot and neutral AC lines with respect to ground.
Abnormal signals that appear between a current carrying line and its associated ground.
Noise signal that is common to both the converter output and return lines with respect to input common.
Signals that appear equally and in phase on two conductors. The noise is seen with respect to the system ground reference point.