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Questions tagged [ifft]

NOTE: please use the FFT tag instead. The FFT is a type of algorithm for quickly computing the Inverse Discrete Fourier Transform.

The IFFT is an FFT algorithm with some different initial permutation of data samples, and often an additional normalization, such that the algorithm computes the IDFT rather than the DFT. The FFT and IFFT are always implemented by the same code.

Related topics include , , , .

More information on the IFFT can be found in the Wikipedia article on the FFT

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De-convolving Instrument Response from Signal (MATLAB)

So I am trying to remove instrument response (phase lag) from some magnetics data. The code I am trying to use is below. I can't figure how to reconstruct the file together properly. The approach I am trying now is to subtract the phase lag and…
IKeneally
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making work the Oouras's FFT

i'm trying to make a simple convolution of two signals. One is a signal (music for example) and the other one is an IR (simple delay like this scheme: IR[0] = 1.0 IR[1->511] = 0 IR[512] = 0.5 IR[513->1023] = 0; so it should make a small echo. I've…
IonOne
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C++ Frequency response <-> Impulse response

I am trying to calculate an actual frequency response from a desired frequency response. fftSize = 128; fs = 8000; I have 2 input arrays: f[] and aDesired[], both of which are Real and length fftSize+1 (DC + Nyquist included). The f[] array is…
Andy
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CUDA Inverse FFT Bug

I have the following code that has bug when doing the inverse FFT. The forward FFT works as I printed the output and verified it. But the inverse does not seem to. Any ideas? Does it look like I have missed a concept? Code -…
viki.omega9
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how I can calculate median,min magnitude of image in matlab

I have a image and in my homework I must calculate fourier transform of it and recover it by 3 different value with min of magnitude values with median of magnitude values with 25% percentage of magnitude values my main picture is and after run…
Yuseferi
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inverse fast fourier transform for frequency range

My problem is to obtain original signal from amplitude spectrum (fft) based on inverse fft but only for some frequency range ex. 8-12 Hz. Could anyone help me? I try to used: xdft=fft(x); ixdft=ifft(xdft(a:b)), %where xdft(a:b) is |Y(f)| for freq…
Karolina
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Recursive FFT Error?

Given below is my java program for FFT. For the input {0,2,3,-1} its returns a false output in complex point representation. import java.io.*; public class test{ static double s[]={0,2,3,-1}; static double[][] re=new double[s.length][2]; static…
u2425
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Does the order of reversing a 2D fft matter?

I have been trying to apply the fft first on the rows and then on the columns resulting from the first application. My question is, when I try to apply the ifft, do I need to apply it to columns first and then rows, the other way or does it not…
Mason
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IFFT from FFT in AForge.Net

I'm rewriting code from Matlab to C#. I'm completely newb at mathematics. I had to use FFT function which I found in AForge.net library, but now I need IFFT. Is this possible to use FFT to compute IFFT in few lines? Aforge.Net FFT declaration: …
apocalypse
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constructing image after applying inverse fourier transform opencv

I am trying to apply fourier transform to an image, by following the code from link http://www.docs.opencv.org/2.4/doc/tutorials/core/discrete_fourier_transform/discrete_fourier_transform.html , after this I am trying to remove the noise components…
Bala
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SFCW radar: Collected Mag&Phase from VNA S21. After IFFT, why does the peak not shift for objects at different distances from antennas?

I am trying to analyze data collected from an antenna experiment. I setup two cantennas next to each other and connected each to a Vector Network Analyzer. I performed a frequency sweep from 2.3 to 2.6 GHz, with step size of 150 KHz, and 2001…
cecchollett
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Fitting on a semi-logarithmic scale and transfering it back to normal?

I am working with IFFT and have a set of real and imaginary values with their respective frequencies (x-axis). The frequencies are not equidistant, I can't use a discrete IFFT, and I am unable to fit my data correctly, because the values are so…
Thore
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How to implement ifft in matlab?

I have been having a big problem understanding the concept of numerical ifft. Consider a function in spatial domain like f(x)=-2/pi*Ln(abs(x)) in which x is between -Lx and Lx. The fourier transform of this function is F(w)=2/abs(w). I want to…
Mohammad Bazrafshan
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I can't make synthesis in Vivado

I work in Vivado HLS, and I want to make a code of IFFT with a test bench. Can any one help me?
Hussein Mroueh
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