MATLAB Program for N point DFT and IDFT of a given sequence

Here is the simple MATLAB code to find out N point DFT and IDFT.

You can get transfer function also using this code. Phase and Magnitude both are plotted separately.

MATLAB Program

Coding:

clc;

clear all;

close all;

Length=input('Enter the length of DFT(for best result enter in terms of power of 2):');

Theta=0:pi/Length:pi;

Num=[0.05 0.033 0.008];

Den=[0.06 4 1];

Transfer=tf(Num,Den);

[Freq,W]=freqz(Num,Den,Length);

grid on;

figure(1);

subplot(2,1,1);

plot(abs(Freq),'k');

disp(abs(Freq'));

title('Magnitude Response');

xlabel('Frequency Index');

ylabel('Magnitude');

grid on;

subplot(2,1,2)

disp(angle(Freq'));

plot(angle(Freq),'k');

title('Phase Response');

xlabel('Frequency Index');

ylabel('Phase');

grid on;

 OUTPUT

Enter the length of DFT(for best result enter in terms of power of 2):16
  Columns 1 through 12

    0.0180    0.0179    0.0176    0.0172    0.0166    0.0159    0.0150    0.0140    0.0130    0.0119    0.0109    0.0100

  Columns 13 through 16

    0.0093    0.0088    0.0086    0.0085

  Columns 1 through 12

         0   -0.1273   -0.2557   -0.3863   -0.5206   -0.6603   -0.8074   -0.9646   -1.1356   -1.3247   -1.5363   -1.7738

  Columns 13 through 16

   -2.0360   -2.3148   -2.5972   -2.8730

Figure:

DFT/IDFT Plot

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