New article about setting up FFT harmonic notch filter

I recently set up a FFT harmonic notch filter - the first time in quite a while.

The new FFT function and documentation are wonderful improvements.

The area is complicated enough I decided to summarize what I learned in my own article - to help crystalize what I learned in my own mind, and perhaps to help others.

My article is only about FFT on copter - and I don’t address many of the advanced FFT capabilities. But I think what I’ve written may have value - especially for someone’s first time using FFT.

Before I circulate it to my associates and colleagues, perhaps the seasoned FFT experts here could take a quick look and offer comments or constructive criticism. I offer thanks for any input.