When you are designing a modem, you’ll typically make heavy use of simulations. Much of the design work is concentrated on the algorithmic part of the device, especially in these days of Software-Defined Radio (SDR), where the actual electronics might…
Now that we are just past Pi Approximation Day (22/7 or July 22), I thought about how to find other fractional approximations of pi with small numerators and denominators. I decided that I was going to brute force this thing, just because I can…
A year is the time that it takes the Earth to complete one revolution around the Sun. You might think that a day is the time that it takes the Earth to complete one rotation of 360 degrees, but that isn’t true. A full 360 degrees rotation takes only about…
This article is a wrap-up of what happened on TomRoelandts.com in 2019.
There is really only one circle. Of course, you have to allow for translation and scaling for this to be true, but I think you’ll agree that a large circle is essentially the same as a small one. The geometrical term for this is similarity. Two objects are similar if…
In the context of images, steganography is the hiding of an image (or other information) within another image. The “carrier image” can then be sent over an untrusted channel (e.g., published on the Internet), and only people that know that the hidden message is there will…
With fractional delay, I mean a delay of a fraction of a sampling period. Introducing a delay of an integer number of samples is easy, since you can do that by simply skipping a number of samples, or buffering them if you don’t want to…
This article is firmly in the category “All work and no play makes Jack a dull boy.”, so don’t take it too seriously… Do you know what an antegooglewhackblatt is? Well, an antegooglewhackblatt is…
Before information can be transmitted using a digital modulation scheme, the information bits have to be mapped to the constellation. Each point in the constellation is known as a symbol, making the full collection of symbols a kind of alphabet of the modulation scheme. For most digital modulation schemes…
Say that you have an ant that lives on an infinite plain with tiles that can be either black or white. The ant can move in the four main directions, and it keeps moving indefinitely, according to the following two simple rules…