Products containing electronics must generally be tested forelectromagnetic susceptibility, as part of their EMC certificationprocess, at the end of their development cycle to ensure that the testis representative of any future use of the product. However, the earlierthat the product as a whole, or the electronic systems that might formpart of the product, can be tested for susceptibility, the more benefitcan be gained from such a procedure. Both a saving in time and cost canbe achieved in the product development process. This paper describes astatistical technique which has been developed for use in the automotiveindustry with a bulk current injection (BCI) test. It has been designedto help overcome the uncertainties in correlating results from such asystem-level bench test with results from the final vehicle-levelsign-off test carried out in a full-threat field within a semi-anechoicEMC chamber. The technique uses a probability distribution function withthe mean transfer function and its standard deviation to estimate therisk of the test system, once installed in a vehicle, malfunctioningwhen that vehicle is exposed to radiation of a particular field strengthand frequency. The effect of vehicle body dimensions on these riskfigures has been examined and a simple mathematical model usingstatistical input data has been produced which shows some agreement withthe measured data
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