How are FFT bins implemented?

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prodigenius

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I'm not really sure if this is the right place for this question, so my apologies if it's not.

A standard N-point FFT yields N frequency bins, but how do programs like MATLAB generate an FFT that takes in N points and returns the content of M frequency bins?

My hunch is that they break N down into L vectors of length M, and then averages the L values of each bin. But, what if N is not divisible by M? Would the the final "leftovers" vector 0-padded?

Thanks for the info!
 

Hi,

Thanks for the response, but I've checked the Wikipedia page several times and it mentions nothing about frequency bins. Where did you find it?
 

Sorry, I thought wikipedia would answer.

My answer would be:
- For an N-point transform, fft rounds n up to the next higher power of two unless N is already a power of two. If the input series contains fewer than n samples, it is padded with zeros up to the next higher power of two. Any additional input samples beyond the first N are not read.

- So yes the last vector would be zero padded. But I recommend you check other references.
 

Hi,
Sorry for interrupting. Can I ask you a few question? Where can I find free source code for fast fourier transform to implement at fingerprint image? It's for image processing.
 

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