Normal Mode Voltage (NMV) is characterized by the fact that the signals on two signal-carrying lines are in phase opposition and their voltage level is inverted. This means that, at the same level, it is positive on one line and negative on the other.
The two signals of a common mode voltage are equal in amplitude, but opposite and in phase opposition. For example, if a voltage of +1.3 V with a phase angle of 90 degrees is applied to input "A", then a voltage of -1.3 V with a phase angle of -90 degrees is applied to input "B" as a push-pull voltage. Typical electronic circuits that are controlled with push-pull voltages are differential amplifiers, operational ampl ifiers and push-pull amplifiers.
If in-phase voltages with the same level are present on the signal-carrying conductors, this is referred to as common mode voltage( CMV).