Nature and classification of disturbances
Measurements in electromagnetic compatibility

Disturbances produced by or affecting equipment can have multiple origins and complex propagation modes:

• by conduction on cables connected to the equipment ;

• by direct radiation from chassis, boards or internal wiring;

• by different types of coupling of the two previous modes.

For a better understanding of possible couplings, we have defined in figure the different types of access possible for a given device.

European standards define access as a specific interface between the device concerned and the external electromagnetic environment.

They also define enclosure access as the device's physical boundary through which electromagnetic fields can radiate or penetrate. For plug-in...