EMI Requirements for Power Supplies and Description of an Enclosed Open Field Test Site

The continuing development of new converter technologies has meant a rapid evolution of the power supplies used in telecommunications equipment. Supplies using these new technologies operate at ever higher frequencies and are potential EMI sources. In concert with this technological development, regulatory bodies such as the FCC have set new or tighter standards to limit EMI problems. This combination of technology and limits changes has put a strain on the evaluation and testing process for new power supplies. For timely introduction of acceptable new power supplies, EMI must be considered during design. Iterations of the evaluation and redesign cycle must be performed quickly; therefore, in house verification of EMI becomes essential. This paper will review: -EMI requirements and measurement methods for power supplies -An "enclosed" open field test site used in the verification of compliance to EMI limits