This International standard specifies methods to measure the radio interference suppression characteristics of passive EMC filtering devices used in power and signal lines, and in other circuits. The defined methods may also be applied to combinations of over-voltage protection devices and EMC filtering devices. The measurement method covers the frequency range from 9 kHz to several GHz depending on the device and test circuit. NOTE Measurement methods in this standard may be applied up to 40 GHz. The standard describes procedures for laboratory tests (type tests) as well as factory tests. Test methods with and without bias conditions are defined. Measurement procedures are provided for unbiased and bias conditions. Measurements under bias conditions are performed to determine potential non-linear behaviour of the EMC filtering devices such as saturation effects in inductors with magnetic cores. This testing serves to show the usability in a specific application (such as frequency converters that produce high amplitudes of common mode pulse current and thus may drive inductors into saturation). Measurement under bias conditions may be omitted if the non-linear behaviour can be determined by other methods (e.g. separate saturation measurement of the inductors used).