Noise is conducted from the DC power supply and GND lines to the switching power supply and radiated out using the AC power supply cable as an antenna. To suppress the noise, the BLMxxP Series (Chip Ferrite Bead) and NFMxxP Series (Chip Solid "EMIFIL®" for DC power supply circuits) are installed close to the power supply connector.

A filter whose rated current is sufficiently larger than the power supply current should be selected.