This application note describes the background, technique and results of EMI measurements on the PCK2001 (CKBF), showing reduced EMI emissions over standard design techniques. Through the use of circuit design, the high frequency EMI emissions from the CKBF were reduced from a standard design approach. These reduced emissions should help a board/systems manufacturer pass FCC and CISPR EMI requirements. BACKGROUND OF EMI, FCC AND CISPR STANDARDS EMI, Electro-Magnetic Interference, is any unwanted electromagnetic signal which may degrade the performance of an electronic device. It is generally thought of as one device creating electromagnetic radiation that interferes with the operation or performance of another device. PCs and PC motherboard designs have to meet standards set by regulatory agencies. Two standards are, FCC (Federal Communications Commission) regulations part 15B, and International Electrotechnical Commission’s International Special Committee on Radio Interference (CISPR) 22B. These regulations specify limits: