DFT Circular Convolution by Overlap Add Method in Matlab

 

Matlab Code:

     clc;

close all;

x=input('Enter the input sequence: ');

h=input('Enter the impulse sequence: ');

n=length(x);

m=length(h);

z=1;

for i=1:4

    if i~=4

        for j=1:m

            X(i,j)=x(((i-1)*m)+1+(j-1));

        end

        for j=m+1:5

            X(i,j)=0;

        end

    else

        for j=1:5

            if j==1

                X(i,j)=x(n);

            else

                X(i,j)=0;

            end

        end

    end

end

disp('Subsets of sequense: ');

disp(X);

 

y1=cconv(X(1,1:5),h,5);

y2=cconv(X(2,1:5),h,5);

y3=cconv(X(3,1:5),h,5);

y4=cconv(X(4,1:5),h,5);

 

Y=[y1(1:m),y1(m+1:end)+y2(1:m-1),y2(m),y2(m+1:end)+y3(1:m-1),y3(m),y3(m+1:end)+y4(1:m-1),y4(m:end)];

Y=Y(1:n+m-1); 

disp('By Overlap Add Method: ');

disp(Y);

Output:

Enter the input sequence: [3 -1 0 1 3 2 0 1 2 1]

Enter the impulse sequence: [1 1 1]

Subsets of sequence:

     3    -1     0     0     0

     1     3     2     0     0

     0     1     2     0     0

     1     0     0     0     0

 

By Overlap Add Method:

    3.0000    2.0000    2.0000    0.0000    4.0000    6.0000    5.0000    3.0000    3.0000    4.0000    3.0000    1.0000