% h1=1+exp(j*pi)+exp(-j*pi);
 
% h2=(1-2*exp(-j*(2*pi/3)))/(1-(1/4)*exp(-j*(2*pi/3)))

% h3=0.5+j*cos(2.5*0.25*pi)-sin(.4*0.25*pi)

w1=angle(h1)
w2=abs(h1)