Ualification Of Radiated EMI Test Sites Using Statistical Methods

Evolving standards (ie: ANSI '263.4) regarding the qualification of Radiated EM1 Test Sites could cause the disqualification of many existing test facilities. A solution is needed, which is both technically and economically sound. This paper suggests that the present criteria for Radiated EM1 Test Site acceptance based on absolute limits of Normalized Site Attenuation (NSA) error, could be replaced by the concept of a Safety Factor (or Site Uncertainty Factor) derived from statistical processing of Volumetric NSA data. Among the issues explored, are repeatability of Volumetric NSA measurements and an examination of the robustness of various statistical processing algorithms under the stress of NSA measurement variability. A specific algorithm is recommended.