Can someone please help me do this problem?

The sinc function is very important in digital signal processing as it is the Fourier transform of a rectangular pulse and is used extensively in interpolation. The sinc function is given by: sinc(t)= sin(π t)/(π t) when t ≠0 sinc(t)=1 when t=0 We will graph the sinc function in 3D to understand better its shape. Write a script that creates a plaid of x and y values that vary between -5 to 5. Choose an adequate step size. Calculate r which is given by: r= √(x^2+ y^2 ) Then, plot using x, y, and sinc(r) using a mesh plot. You can either write your own function for sinc or use MATLAB’s built in function. Include your code and plot below. Skills – 3D mesh plots in MATLAB, meshgrid.

[Rehab Mohamed`]

I started with these equations, but i don't know if that's right or not x= -5:1:5; y= -5:1:5; r= sqrt(x.^2 +y.^2);

Answer 1

[Star Strider]

You have to adapt your ‘sinc’ function to use ‘r’ rather than ‘t’, and use element-wise division. Use the meshgrid function to create the appropriate ‘X’ and ‘Y’ matrices to calculate ‘r’.

Define ‘x’ and ‘y’ as:

x= -5:0.1:5; 
y= -5:0.1:5;

to get acceptable resolution in the plot.

[Rehab Mohamed`]

I did two codes but none of them is working however, the first one worked but i don't know why it is not working again!! 1. x= -5:1:5; y= -5:1:5; [xx,yy]=meshgrid(x,y); r= sqrt(xx.^2 +yy.^2); mesh(xx,yy,sinc(r))

2. [X,Y]=meshgrid(-5:1:5); R= sqrt(X.^2 + Y.^2); Z= sin®./R; mesh(X,Y,Z)

[Star Strider]

Your second code works. You need to make two changes:

[X,Y]=meshgrid(-5:0.1:5);                   % Use A Mesh With A Smaller Step Increment
R= sqrt(X.^2 + Y.^2);
Z= sin(pi*R)./(pi*R);                       % Multiply By ‘pi’
mesh(X,Y,Z)

That will give you the result you want.

[Rehab Mohamed`]

I did that, but it is not running ! that's the error that appears each time I try to run it, (Error in mesh2 (line 4) mesh(X,Y,Z)

[Star Strider]

The code I posted runs without error.

You did not say what the error is that you are getting.

[Rehab Mohamed`]

Oh ok, i figured out what was wrong. thanks for your help

[Star Strider]

My pleasure.