Hi All,
My question is as follows. When calculating an N-point IFFT with the
inputs conjugate symmetric (real output), this can be performed using a
single N/2-point IFFT and some pre and post processing.
Is there any method to do this (use a single N/2-point IFFT) with half the
inputs set to zero instead of the complex conjugate? (and thus getting the
complex analytic output instead of the real output?)
Thanks, Nadav
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Posted by Mark Borgerding●May 11, 2005

nadavf wrote:
> Is there any method to do this (use a single N/2-point IFFT) with
half the

> inputs set to zero instead of the complex conjugate? (and thus getting the
> complex analytic output instead of the real output?)
>
> Thanks, Nadav

I won't call it impossible ... but I doubt it.
Look at the inverse operation that would be possible if that were true.
It would be equivalent to zero-padding a length N sequence to size 2N
and doing a 2N fft on it for the cost of a 1N fft. In other words,
you'd get the increased/interpolated frequency resolution for free.
-- Mark

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