Monthly Archives: June 2011

How to Interview Engineers

Posted on 29-June-2011 by mathscinotes

My youngest son has a long drive to and from work everyday. During his drive home, he frequently calls me to help him pass the time. During a recent drive, we talked about how I interview engineers, which I have done hundreds of times. I have a fairly standard interview methodology. The key part of any interview is how you go about grading the applicants. Continue reading →

Posted in Management | 1 Comment

Another Analog Design Legend Dies

Posted on 20-June-2011 by mathscinotes

I just saw the announcement that Bob Pease died in a car accident after leaving a memorial to Jim Williams, another analog legend. This is very sad. I have read everything that Bob Pease wrote. His column for Electronic Design, "Pease Porridge," was required reading for my crowd. Continue reading →

Posted in Electronics | Comments Off on Another Analog Design Legend Dies

Density of a Neutron Star

Posted on 19-June-2011 by mathscinotes

Television science programs frequently talk about black holes and neutron stars. A common quote during these programs is something like "a teaspoon of neutron star stuff weighs a billion tons" or some other similar statement. I always find numbers like these interesting to look at in detail. Continue reading →

Posted in Astronomy | Comments Off on Density of a Neutron Star

The Papoulis Filter (aka Optimum "L" Filter)

Posted on 17-June-2011 by mathscinotes

Analog engineers often have to design filters, which generally entails a lot of polynomial manipulation. Since I am currently designing some active filters, I thought it would be worthwhile documenting a filter function that I am using right now, but that is not widely known. This is the Papoulis or Optimum "L" filter. For this article, I will refer to this filter as the "L-filter." The "L" stands for Legendre, a mathematician whose like named polynomials are used in the derivation of the function. Continue reading →

Posted in Electronics | 13 Comments

The Passing of an Analog Electronics Giant

Posted on 14-June-2011 by mathscinotes

I just saw the announcement that Jim Williams passed away. This guy was an inspiration to me. His apps work at National Semiconductor was a model for the industry. His articles in magazines like EDN provided real-world examples of elegant analog design techniques. His books, particularly Analog Circuit Design: Art, Science and Personalities, provided wonderful examples of problem solving. He will be missed. Continue reading →

Posted in Electronics | Comments Off on The Passing of an Analog Electronics Giant

Filter Design Details

Posted on 10-June-2011 by mathscinotes

During a recent circuit design review, I saw the need for a simple two-pole filter in one region of the circuit. As I thought about, this filter might be a good example to work through here in the blog. While the application is rather routine, it does illustrate the general process involved in designing one of the most common forms of a low-pass filter. Continue reading →

Posted in Electronics | 3 Comments

Solar Photons

Posted on 4-June-2011 by mathscinotes

I was watching "How the Universe Works" on the Science Channel and they had a really interesting discussion on stars and photons. During the show, they mentioned that photons generated in the center of the Sun take 4000 years to get to the surface. From the surface, the photons only take 8 minutes to get to the Earth. As part of my campaign to promote active television watching, let's take a look at where these numbers come from. As part of this effort, I will use Mathcad for the calculations and as a programming tool for a simple simulation Continue reading →

Posted in Astronomy, General Science | 2 Comments