Uncertainty Analysis and Novel Test Procedures Performed with a Realtime Time-Domain EMI Measurement System

Time-domain EMI Measurement Systems allow to reduce the measurement time by several orders of magnitude. In this paper novel test procedures for radiated emission measurements based on a realtime time-domain emi measurement system are presented. Those test procedures take advantage of the parallel calculation of the spectrum at several thousand frequency bins. By a full maximization procedure full automated measurements can be performed. By an enhanced pre- and final scan a test procedure is presented that reduces test time by at least one order of magnitude. The proposed test reduces the critical parameters that have to be selected by the operator. Measurements have been performed in the frequency range 30 MHz - 1 GHz and compared with the results obtained by an EMI receiver. The long term stability of the emission of a brush motor is investigated. A measurement uncertainty analysis based on a reliable statistic of 200000 quasipeak values. The standard deviation as well as the histogram of the probability density function is calculated and evaluated.