IFFT calculate only one timesample
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T on 6 Mar 2017
Answered: Star Strider on 6 Mar 2017
I have a frequency signal and I apply an IFFT to it. This results in the time domain x(n) which has N samples. But I am really only interested in the value of x(n) for one specific n. Is there a way to speed up the calculation compared to just applying ifft and generating the entire signal x? I will have a lot of these operations, so even a small speed gain makes a difference Thanks
Star Strider on 6 Mar 2017
‘Is there a way to speed up the calculation compared to just applying ifft and generating the entire signal x?’
No. The Fourier transform calculates a series of complex exponentials (with a real cosine and imaginary sine term) to your entire signal, both when transforming to the frequency domain and when inverse-transforming to the time domain. Because of this, you cannot transform only one value. You have to transform the entire signal.
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