Broadband EMI Control for Data Processing and Office Equipment

The paper, "EMI Control for Data Processing and Office Equipment," presented at the EMC Symposium and Exhibition, Montreux, Switzerland in May 1975, resulted from technology studies conducted in IBM over the past decade on the electromagnetic emanation characteristics of electronic data processing (EDP) and office machine (OM) equipment. That paper described 1) the development of a generally worst case, narrowband interference model for most classes of communication services in the United States, and 2) a general approach to narrowband radiated and conducted limit setting with examples appropriate to EDP/OM equipment. This paper extends the scope of that work to include control of broadband emanation sources which can exist independently of or İn conjunction with narrowband sources in EDP/OM equipment (products). While both narrowband and broadband noise sources have the potential for rf interference with communication services, our experience with broadband problems has shown this class of sources to be much less significant than the low incidence of actual narrowband EDP interference problems examined in the initial paper [1]. Limits are discussed considering the empirical data base and need for international harmonization of interference requirements.