Henry John Orchard

Henry John Orchard was a professor emeritus of electrical engineering at the UCLA Henry [Samueli School of Engineering and Applied Science] and an authority on filter design and network theory. He died June 23 of 2004 at his home in Santa Monica of respiratory failure. He was 82.
In a monumental breakthrough publication, he explained the "secret" behind the low passband sensitivity of doubly loaded reactance two-ports and showed how to design active two-ports that retain this key attribute. Among Professor Orchard's key contributions was the development of a systematic process for the computer-aided design of filters. During the early years of computer-aided filter design, when the synthesis of a single circuit required several days of multiple-precision computation, his method had an important beneficial effect. He was instrumental in introducing into switched capacitor filter design the bilinear s-z mapping, previously used solely in digital filter design, and in developing a methodology that allowed the use of arbitrary active-RC models for switched-capacitor filter syntheses.