% Pole-Zero Demonstration 3D Plot
% F(s)=(s+20)/(s^2 + 100)
% The magnitude is limited to 1 to make the plot better
% Authored by Jeffrey N. Denenberg on 8 April 2004

% Establish the function of s
% B is the numerator and A is the denominator
B = [1,20] 
A = [1,0,100]

% Set up the values for s
S=zeros(50,50);
for n=1:50
for m=1:50
S(n,m)=(n-25)+j*(m-25);
end
end

% Populate F(s)
F=zeros(50,50);
for n=1:50
for m=1:50
s=S(n,m);
numerator=B(1)*s + B(2);
denominator=A(1)*s^2 + A(2)*s + A(3);
F(n,m)=numerator/denominator;
if abs(F(n,m))>1
F(n,m)=1;
end 
end
end

% Plot the magnitude of F(s) in 3D
X=-24:25;
Y=-24:25;
mesh(X,Y,abs(F));

% Done