Insertion loss data assumes a 50 OHM circuit, however 50 OHM circuits seldom exists in actual applications. Therefore, insertion loss readings are not supposed to represent actual performance of noise suppression but a reference for comparison among different units. This can be used for evaluation of product conformity when inspecting the EMI Filters. To verify actual effectiveness in noise suppression, a filter has to be mounted in the intended equipment for the EMI filters’ application and be subjected to a conduct emission test in a shielded room.