Category Archives: Electronics

Crest Factors for QAM Signals

Quote of the Day If you want to succeed you should strike out on new paths, rather than travel the worn paths of accepted success. — John D. Rockefeller Introduction I need to do a quick calculation of the Crest … Continue reading

Posted in Electronics | 22 Comments

Trapezoids Better Than Sinusoids?

Sinusoids hold a revered place in electrical engineering -- they should. However, I do encounter quite a few trapezoids in telecom power systems. During a meeting the other day, I was asked "Why do we use trapezoidal waveforms for Alternating Current (AC) signals like ringer voltages and remote power systems." It was a good question. I have written about the trapezoidal waveform before, but I have never explained why the trapezoid is used so frequently. Continue reading

Posted in Electronics | 7 Comments

Design Review of Four Transistor Current Source

One of the engineer's in my group asked if I had any information on how a four transistor current source works. I decided that to pull together a quick Mathcad worksheet. The Wikipedia refers to this current source configuration as … Continue reading

Posted in Electronics | 3 Comments

Quadrature Modulators Solve Old Problems with Self-Calibration

Introduction I was reading EETimes this month when I saw an interesting article on analog quadrature modulators (AQMs). I have not looked at these devices in a while and I noticed that some of my early issues with AQMs may … Continue reading

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How Much Radioactive Material is in a Smoke Alarm?

Quote of the Day MacArthur could never see another sun, or even a moon for that matter, in the heavens, as long as he was the sun. - Dwight Eisenhower on Douglas MacArthur Introduction I was watching this Youtube video … Continue reading

Posted in Electronics, General Science | 5 Comments

Variable Voltage Power Supply Control Input Design Example

Introduction An engineer in my group is learning Mathcad and he asked me if could I show him how to use Mathcad to design the control input for a variable voltage power supply. After looking at the problem, I decided … Continue reading

Posted in Electronics | 2 Comments

A Good Analog Computation Example

Introduction I am always looking for real-world examples of analog computation and this blog post will discuss one of the best examples of analog computation that I found. I found this little gem in EDN magazines' Design Ideas section, which … Continue reading

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Laser Slope Efficiency and Curve Fitting

Introduction I have spent much of my summer dealing with issues related to the high temperature characteristics of lasers. These issues have stirred within me an interest in laser slope efficiency . Slope efficiency, also known as SE, is simply … Continue reading

Posted in Electronics, Fiber Optics | Tagged | 4 Comments

Laser Tracking Error and Curve Fitting

Introduction I had a request for an example of how the output power of a laser varies with temperature. We call this parameter tracking error. Tracking error varies from part to part and the manufacturers simply put a bound on … Continue reading

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Lighting My House Number and Designing with Phototransistors

Introduction I have had several people say that my house number is difficult to read at night. The number consists of four digits mounted on a structural column that holds up a section of my roof. In response to these … Continue reading

Posted in Construction, Electronics | Tagged | 5 Comments