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Re: [sc-users] [DSP] zero padding = interpolation ?



On 11 Jun 2009, at 13:18, Zlatko Baracskai wrote:

Hi All,

A quick debate here -

JOS states in one of his online bits that zeropadding a signal before FFT would obviously give you a larger FFT size but that it will not contain significant spectral info as it is essentialy intrepolation of the magnitude values anyway.

This was in contrast to what my good old DSP teacher Peter Pabon taught me and yesterday I found a graph describing zero padding in Udo Zolzers DAFX first chapter that clearly shows that the new magnitude points in his example do give a better frequency resolution. It was also explicitly advised to increase frequency resolution
without compromising time resolution.

As I've said to you before, it gives better 'resolution' in terms of the spacing of the points in the result. What it does not give you is an improved ability to 'resolve' closely spaced spectral peaks. The only way to do that is to increase the duration of your input signal before zero padding. Simply put, these are two separate, although related, kinds of resolution, which are unfortunately easy to confuse.

S.




Anyone?

If someone has a zeropadding snippet, I'dd love to see it and try a few things,
can it be done with existing UGens anyway?


Cheers

Zlatko


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