About our authors Professor James W. Nilsson taught at Iowa State University for 39 years. Since retiring from Iowa State he has been a visiting professor at Notre Dame California Polytechnic at San Luis Obispo and the United States Air Force Academy. In 1962 he coauthored (with R.G. Brown) Introduction to Linear Systems Analysis (John Wiley & Sons). In 1968 he authored Introduction to Circuits Instruments and Electronics (Harcourt Brae and World). Professor Nilsson received a Standard Oil Outstanding Teacher Award in 1968 the IEEE Undergraduate Teaching Award in 1992 and the McGraw-Hill Jacob Millman Award in 1995. In 1990 he was elected to the rank of Fellow in the Institute of Electrical and Electronics Engineers. Professor Susan A. Riedel has been a member of the Department of Electrical and Computer Engineering at Marquette University since 1981. She also holds a clinical research appointment in the Department of Orthopaedics at the Medical College of Wisconsin and was a visiting professor in the Bioengineering Unit at the University of Strathclyde Glasgow Scotland as a Fulbright Scholar during the 1989-90 academic year. She has received two awards for teaching excellence at Marquette and was recognized for her research contributions with an award from the Chicago Unit of the Shriner's Hospitals.