New concept about common mode noise

We will show that in a typical switched mode power supply (SMPS), 3 types of conducted electromagnetic interference exist. This is a further development of the well known and widely applied theory that limits the type of noises to differential mode (DM) and common mode (CM). In this paper, the 3 types of noise are categorized as: DM, single mode (SM) ground noise and CM ground noise. The new concept of the SM is useful in explaining how the symmetry can significantly reduce ground noise (or in traditional concept, CM).