AnsweredAssumed Answered

vrf ifft amplitude scaling

Question asked by VRFuser on Apr 18, 2006
Nick,

Unless you have a particular need to have the "correct" absolute scale in the frequency domain, I would not use the scaling function. Just do the FFT, multiply by your filter function and do the IFFT.
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Bill Ossmann
Philips Ultrasound


"Nick Evans" <nick@genesysibs.com> wrote on 04/18/2006 11:39:16 AM:

> Hi All
>
> Can anyone point me in the direction of how to scale the amplitude
> of an inverse fft.   Vee has an example of how to scale the
> amplitude of an fft such that the spectral peaks in the frequency
> domain have amplitudes equal to those in the time domain.  I am using
> this function basically to convert a waveform into the frequency
> domain.  Then I’m manipulating the data with some shaping curves and I
> want to convert it back to the time domain.  The problem is that if I
> strictly reverse the process in the “scale fftâ€
> it does not always give me the correct amplitude back in the time
> domain.   I sometimes end up with huge numbers in the time domain.
>
> Any help would be greatly appreciated.
>
> Thanks
>
> Nick
>
> ---
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