In Memory of Professor Middlebrook

This evening I learned that my adviser at Caltech, Professor David Middlebrook, passed away.

The patents which I hold in stethoscope and sound sensing technology are, in no small part, the fruits of Dr. Middlebrook's teaching. His course, which won him both Caltech and national teaching awards, was titled "EE114 - Electronic Circuit Design". But it could just as well have been titled "PHIL114 - How to Think about What Really Matters."

His course was virtually unique in the world of engineering. On the first day of class, he handed out the first homework assignment and told us, "You've all seen circuits like this before and you know that with 4 or 5 pages of math you can find the exact equations that describe the circuit behavior. Do that in this class, and you'll get zero! What I expect is that you make intelligent judgments about what matters in this circuit. In one page, I want equations that approximate the circuit behavior with 90% accuracy. Anyone can do math, but only those who really understand can figure out what's important and what's not, and distill that into simple mathematical models."

While most electronics instructors teach math, Dr. Middlebrook taught insight. While most electronics courses are forgotten due to the tedium of mathematical analysis, he taught us to use mathematics intelligently, to make it useful and powerful.

When I started exploring electronic stethoscope design, I wanted to maintain the authenticity of stethoscope sound, with the benefit of electronic amplification and signal processing. There were two choices: (a) Do a highly detailed analysis of the acoustics of the stethoscope with complex mathematics that addresses every aspect of sounds traveling up the tubing and hitting the eardrums - math ad infinitum sans any judgment, or (b) Think, determine what matters most and eliminate the rest - less math, more judgment. Dr. Middlebrook's education led me to "b", resulting in a clean, simple design that really does sound like a stethoscope, but better. It's still mathematical, but it's elegant mathematics!

Beyond education, Dr. Middlebrook's contributions to the world of technology surrounds everyone reading this. Have you noticed how small your cellphone and iPod charger have become in the last few years? Notice how you can take it anywhere in the world and it adapts to all voltages? Have you realized how battery life in most accessories has improved despite using smaller batteries? All this is due to what's known as 'switching power supplies" a field virtually invented by Dr. Middlebrook and his research partner at Caltech, Dr. Slobodan Cuk.

Thank You, Dr. Middlebrook.