Electromagnetic Compatibility (EMC) is the ability of an appliance or system to operate satisfactorily in its electromagnetic environment without causing electromagnetic interference (exceeding the limits specified in Standards). It can not be measured directly. In order to be able to describe quantitatively the EMC, we distinguish:
– electromagnetic interference (EMI), which indicates the interfering power of an electrical equipment
– electromagnetic immunity (susceptibility) which indicates the ability to withstand disturbances (“susceptibility to electromagnetic disturbances” … EMS = electromagnetic susceptibility).
Whether it is emissivity (perturbations) or immunity (suceptibility), the distinction between radiated waves and conducted waves is also made in each case. Radiated mode tests generally require a large number of means, in particular with regard to the test site: anechoic chamber or free field (OATS).
To summarize : all electrical equipment is both source of disturbance (emission aspect) and victim of disturbances (immunity aspect) and this equipment can emit or receive disturbances by two distinct channels: conduction and / or radiation.