Hi,
what additional explanation do you expect?
High impedance --> less noise current --> less noise voltage.
Klaus
More detailed:
Let´s view only one path: Maybe it´s inductance is 1mH
--> for commom mode (noise) both path´s inductance is added to 1mH + 1mH = 2mH
--> for differential mode (usual energy flow) both path´s inductance is subtracted to 1mH - 1mH = 0mH
For common mode the vector in both paths go from left to right.
For differential mode: The upper path vector goes from left to right, but the lower path vector goes from right to left.
Klaus