This design note tackles design of a simple PWM signal generator using a square wave signal and an RC circuit with a variable time constant.
What are Design Notes?
Design notes are a way in which an engineer might present how he or she
decided to solve a particular design problem. They cover possible
solutions and go in-depth into one of them. This genre must not be
confused with the standard school project report; design notes focus on
intriguing the reader and showing them what you have done. I believe this
manner of communication is very effective.
The following design notes cover all kinds of different
electronics-related design problems which I did over the course of one
year at university. They are unfortunately in norwegian, and will probably
not be translated.
#1: PWM signal generator
#2: Class A power amplifier circuit
In this design note I present a very simple class A power amplifier circuit.
#3: Optical data transfer (lasers!)
This was a cool one. I designed and implemented a system for transferring data optically with a laser, and I was successful in transferring a square wave nearly 40 meters.
#4: Anti-alias filter (Butterworth)
Here I designed an anti-alias filter with very specific parameters based on an active Butterworth filter with Sallen-Key structure.
#5: Sinusoidal waveform generator
If you know your Fourier transform, you know that you can apply a low-pass filter to a square wave and extract the fundamental sine frequency. Here I designed a relaxation oscillator and a low-pass filter to get a sine wave with less than 5 % THD.
#6: Binary FSK communication system
This is one of my favourites as it involves a lot of interesting programming. I designed software to decode a binary frequency-shift keyed signal on an Arduino, which was surprisingly difficult.
