FFT Analysis


#1

The the items in the next paragraph are taken from Stack Overflow. Should FFT(x) , FFT(w), and FFT© be calculated with rectangular windowing, or with rounded windowing such as Hann or Hamming? The copyright symbol should be an C inside parentheses.

Take time domain buffer x, make a windowed copy w.
Sx = FFT(x), Sw = FFT(w)
c = Log of square magnitude of Sw
Cx = FFT©
Estimate fundamental (and maybe harmonics) using Cx
Use Sw to do cunning phase trick on fundamental (or higher harmonic) bin(s)
And/or use Sx to do quadratic bin fit around fundamental (or higher harmonic)

Thank you for considering these questions about FFT analysis. Please share your ideas about what can be done with Sx, Sw, and Cx.

@ Stephen Kyne
Thank you for the link. It will take a long time to read the whole thing.
https://ccrma.stanford.edu/~jos/sasp/


#2

It’s all in here: https://ccrma.stanford.edu/~jos/sasp/


#3

Or a more gentle introduction here: http://www.dspguide.com/pdfbook.htm


#4

Thanks Amina, this looks like a quite exhaustive and compact source of FFT knowledge I didn’t know of until now :open_mouth:


#5

Yeah, it’s a great link to bookmark and then never read ever again!

I guess it’s more of a reference if you have something specific to look up.


#6

I’m picturing an astronaut on the moon pointing to the earth. “It’s all in here.”