       Need help to solve FFT and IFFT by mathematica

• To: mathgroup at smc.vnet.net
• Subject: [mg117568] Need help to solve FFT and IFFT by mathematica
• From: Gazi Habiba Akter <gazihabiba02 at gmail.com>
• Date: Wed, 23 Mar 2011 02:53:01 -0500 (EST)

```Hello,
I want to solve FFT and IFFT in the same problem. My  function  is
Exp[2*(1 + I*c)*T^2].

For FFT, I used the following code:

ClearAll["Global'*"]
c = 0;
f[t_] = Exp[-(1 + I*c)*2*t^2];
sampleTime = .01;
data1 = Table[f[t], {t, -5, 5, sampleTime}];
freq1 = Fourier[data1];

now I need to do IFFT of  ( freq1*Exp[-0.5*(z/(1 - I*v))] )  function.
Before perform IFFT,  i converted Exp[-0.5*(z/(1 - I*v))]  into
frequency  data  as same matrix of  freq1. Here is my code:

s = Exp[-0.5*(z/(1 - I*v))];
data2 = Table[s, {v, 0, 2000*Pi, 2*Pi}];

Then i performed IFFT by

freq2 = InverseFourier[data2*freq1];

Now i am confused  whether my IFFT solution way is correct or not. I
got idea of  sampling frequency , Table[s, {v, 0, 2200*Pi, 2*Pi}]
from some tutorial.  Is there any another way I can calculate
IFFT for my function???

Finally i want to plot  (Abs[freq2])^2 with respect to time for
different value of z.
z=1;
ListLinePlot[(Abs[freq2]*Abs[freq2]), PlotRange -> Full]

But i got the curve  in terms of data value 0 to 1000.

How can i get the curve with respect to time now??

Thanks,
Gazi

```

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