MATLAB program to find the Fourier transform of an exponential curve

Progam code

clc;

clear all;

close all;

t=0:0.001:1;

a=input('Please enter the multiplication factor of an exponential curve ');

cwtstruct = cwtft(exp(a*t),'plot');

Example of output

Please enter the multiplication factor of an exponential curve  5

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MATLAB program to find the Fourier Transform of cosine wave

Program code

clc;

clear all;

close all;

t=0:0.001:1;

cwtstruct = cwtft((cos(2*3.14*1000*t)),'plot');

Output

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MATLAB program to find out the Fourier Transform of sinusoidal waveform

Program code

clc;
clear all;
close all;
t=0:0.001:1;
cwtstruct = cwtft((sin(2*3.14*1000*t)),'plot');

Output

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MATLAB program to find DFT and IDFT using matlab functions

Program Code

%DFT and IDFT using matlab functions
clc;
close all;
clear all;
x=input('Please enter the sequence x(n)=');
N=input('Please enter the length of the DFT N=');
X=fft(x,N);
n=0:length(x)-1;
subplot(311);
stem(n,x);
title('Input Sequence');
subplot(323);
n=0:length(X)-1;
stem(n,X);
disp('DFT of input sequence is ');
disp(X);
title('DFT');
subplot(324);
stem(n,abs(X));
title('Magnitude spectrum');
subplot(325);
stem(n,angle(X));
title('Phase spectrum');
xr=ifft(x,N);
subplot(326);
stem(n,abs(xr));
title('IDFT');
disp('IDFT of input sequence is ');
disp(xr);

Example of Output

Please enter the sequence x(n)=[1 2 3 4 5 6 7 8 9]
Please enter the length of the DFT N=6
DFT of input sequence is 
  Columns 1 through 4

  21.0000 + 0.0000i      -3.0000 + 5.1962i       -3.0000 + 1.7321i       -3.0000 + 0.0000i

  Columns 5 through 6

  -3.0000 - 1.7321i          -3.0000 - 5.1962i

IDFT of input sequence is 
  Columns 1 through 4

   3.5000 + 0.0000i       -0.5000 - 0.8660i         -0.5000 - 0.2887i       -0.5000 + 0.0000i

  Columns 5 through 6

  -0.5000 + 0.2887i         -0.5000 + 0.8660i

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