I just saw a great animation illustrating the Fourier series decomposition of a square wave. Check it out. The video includes two different animations, so be sure to watch it all the way through to see the second one. ... read more >>

Note: I really didn't expect to be writing about the FFT two weeks in a row. But ready or not, here we go!... read more >>

My last meeting of the day ended just a little while ago, and I was starting to think seriously about figuring out a blog post for this week. What to write about? That's when I happened to see that Cleve posted just yesterday about the FFT. Ah ha! I'll write about that, too (in honor of National Blog About the FFT Week).... read more >>

A reader asked in a blog comment recently why a vertical line (or edge) shows up in the Fourier transform of an image as a horizontal line. I thought I would try to explain this using the simplest example I could think of. ... read more >>

One of the discrete-time Fourier transform properties that many people learn is that if a sequence is conjugate symmetric, , then the Fourier transform is real. ... read more >>

In my Fourier transform series I've been trying to address some of the common points of confusion surrounding this topic. For today's espisode I want to look at how to use the fft function to produce discrete-time Fourier transform (DTFT) magnitude plots in the... read more >>

I recently asked for your advice about how to continue my Fourier transform series. I appreciate all the enthusiastic and helpful responses. I'd like to continue focusing on some basic points that confuse folks who don't have an extensive signal processing background: ... read more >>

Last fall I started posting occasionally about Fourier transforms. This topic causes much confusion, which is particularly unfortunate given how many people are interested in it. ... read more >>

OysterEngineer (I love that name!) asked some interesting questions in response to my last Fourier transform post, which concerned the relationship between the discrete-time Fourier transform (DTFT) and the discrete Fourier transform (DFT). ... read more >>

It's finally time to start looking at the relationship between the discrete Fourier transform (DFT) and the discrete-time Fourier transform (DTFT). Let's look at a simple rectangular pulse, for . The DTFT of is: ... read more >>