This is part one of a rather basic article that describes the complete signal path of a radio meteor, from the sinusoidal carrier wave that is initially transmitted, to the spectrogram that is typically used as the final result in the receiving chain. I have presented this material at…
In digital communications, the measure of the signal to noise ratio of a signal is Eb/N0. Why is that? To figure it out, let’s start from the classical SNR, which is the ratio of the average signal power S to the average noise power N, given by…
![Simulation of two merging black holes [image: SXS, the Simulating eXtreme Spacetimes (SXS) project]](https://tomroelandts.com/sites/tomroelandts.com/files/styles/thumbnail/public/field/image/merging-black-holes.jpg "Simulation of two merging black holes [image: SXS, the Simulating eXtreme Spacetimes (SXS) project]")
Not that I am going to try, but it is difficult to underestimate the importance of the first detection of gravitational waves for physics. Apart from the fact that it is another gloriously successful test for general relativity, it actually opens up a new observational window on the universe…
This article presents spectral reversal, a technique to turn a low-pass filter into a high-pass filter. Spectral reversal is an alternative for spectral inversion, as described in How to Create a Simple High-Pass Filter. Starting from the cutoff frequency…
When researching what to include in The Moving Average as a Filter and Variations on the Moving Average, I came across a lot of references to applications in the financial sector. This is not my forte, but, just for fun, I gave a few of the moving averages that are used there the same treatment as the filters in…
The low-pass single-pole IIR filter is a very useful tool to have in your DSP toolbox. Its performance in the frequency domain may not be stellar, but it is very computationally efficient. A low-pass single-pole IIR filter has a single design parameter, which is the decay value d. It is customary to define parameters…
The moving-average filter is a strong performer in the time domain, but not in the frequency domain. For those cases where you have to work with data for which both domains are important, there are “weighted” versions of the moving average that are…
Say yes to HTTPS! As of today, my sites (https://tomroelandts.com/ and https://impulseresponse.eu/) require HTTPS. HTTPS is the secure version of HTTP (the Hypertext Transfer Protocol), the protocol that your browser uses to show you a website…
This article is a wrap-up of what happened on TomRoelandts.com in 2015.
After introducing several types of filters in previous articles, this article compares their performance in the time and frequency domain. This is important because the choice of filter is strongly influenced by the domain in which the useful information in your signal is situated…