The problem illustrated here is representative of all conducted Electromagnetic Interference's : an electrical appliance, here for instance a Switched Mode Power Supply (SMPS) emmits conducted noise in the main. Consequently, other apparatus to the same main can be disturbed.

The aim of this chapter is to present how the standards propose to characterise the noise level emitted by electrical apparatus.

First of all, it is necessary to represent the main, using a more convenient apparatus : this is the LISN

The LISN efficiency should be ensured on a large bandwidth, since its role concerns two frequency ranges :

• The main frequency : f_main
• The Disturbances frequency : f_noise