% Filter Yn = Xn  +  X(n-1) plot the Impulse response and the frequency response.
% Measure the gain at DC, 2K, 4K, 6K and 8K.
% Measure the max and min gain and where they occur, the bandwidth if applicable and 
% the roll off rate Determine what type of filter it is.
% f=f*(180/pi);
% h is in rad/sample by default
clear

a=[1];
b=[1 1];                                % 1*Xn  +  1*X(n-1)
%impz(b,a)                           % impuls response
[h,f,units]=freqz(b,a,500);
Mag=abs(h);
Ang=angle(h);

plot(f,Mag);title('Frequency vs Gain');