Should we be more concerned with emission compliance or immunity protection? The field of EMC deals with electrical equipment operating within an “intended” environment of use such as residential areas, commercial facilities, industrial factories, military applications, space, and the like. When we examine environment of use and product utilization during certification testing, what aspect of EMC should we be more concerned with, emissions or immunity?
Almost everyone has a wireless phone, iProduct, wireless Internet, tablets, laptops, e-book readers as well as numerous other electrical devices most of which are hand-held. The RF spectrum supports an unlimited number of devices in narrow frequency ranges depending on application of use and international allocation of the spectrum. Intentional transmitters must share a limited bandwidth within the frequency spectrum at the same time. Everywhere we go we are subjected to nearly an unlimited number of RF signals sharing a narrow portion of the frequency spectrum with all having about the same field strength intensity.
Will one unintentional radiator with an single RF signal a few dBs above a specification limit really cause harmful interference to other electrical devices that may be co-located within a specific environment of use? With an unlimited amount RF energy in the environment today propagating from billions of hand-held devices at high levels of signal intensity, can this one unintentional signal a few dBs above a pre-defined specification limit really create a serious EMI event? This must be taken into consideration since almost all products sold today has to meet stringent European requirements that mandate numerous immunity tests, in addition to emissions?
Should we be more concerned with increasing immunity protection of all electrical products against harmful interference due to a narrowband signal of high intensity that is usually hidden or masked in a very noisy broadband environment of legally licensed transmitters which will never cause harmful disruption, or making sure that emission requirements are met against a specification limit that has, in reality, a causal relationship to many different environments of use?
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