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Log Scale FFT ?

Started by edwardehopkins ●April 4, 2005
Does anyone know if there is a way to compute an IFFT over a log scale of
sampled frequencies?  In other words if I have a frequency response that
is on a log scale (base 10) what does this mean in the time domain?



		
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Reply by Jerry Avins ●April 4, 20052005-04-04
edwardehopkins wrote:

> Does anyone know if there is a way to compute an IFFT over a log scale of
> sampled frequencies?  In other words if I have a frequency response that
> is on a log scale (base 10) what does this mean in the time domain?
> 
> 
> 
> 		
> This message was sent using the Comp.DSP web interface on
> www.DSPRelated.com


What would a logarithmic IFFT be? Log-spaced time ticks? For an FFT 
(amplitude only), you can do a very fine-grained one, then lump the 
results into log-spaced chunks.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
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Reply by Lars ●April 4, 20052005-04-04
"edwardehopkins" <edward.e.hopkins@dartmouth.edu> wrote in message
news:jqKdnYjDaOiAoszfRVn-3Q@giganews.com...

> Does anyone know if there is a way to compute an IFFT over a log scale of
> sampled frequencies?  In other words if I have a frequency response that
> is on a log scale (base 10) what does this mean in the time domain?


How strict is the log-scale criteria? Would an approx do? If so do a search
on warped fft.

Second google result:
http://www.acoustics.hut.fi/~aqi/papers/waspaa01.pdf


cheers,
Lars