Variability studies on EMI data for electronic, telecommunication and information technology equipment

Data variability has long been a problem for radiated emission testings of electronic, telecommunication and information technology equipment. When a piece of electronic equipment undergoes electromagnetic interference (EMI) test, the inherent data variability is inevitable even with known test facility uncertainties. This study presents a methodology for analyzing this variability based on a modified analysis of variances (ANOVA), with polynomial regression analyses. The data variability is estimated after the prototype has been built in a design laboratory. The analytical analysis results can also be used to provide confidence limits for internal in-process EMI control when the equipment is mass-produced.