how to design a notch filter in matlab

i wnat to design a notch filter in my project

Answer 1

[Aquatris]

Here is one way;

alpha= 2000;    % determines the depth
f    = 650*2*pi;% notch filter frequecy (rad/s) 
x    = 0.1;     % notch filter damping, determines width
Gn1=tf([1 2*x*f/alpha f*f],[1 2*x*f f*f]);% notch filter TF