MATLAB and C Programs - Digital Signal Processing: A Practitioner's Approach - page 178

% introduces r zeros between
% two succesive samples
% e:\matlab\toolbox\rf
j=1:length(x);
k=j*r-r+1;
n=length(k);
y=zeros([1 n*r]);
y(k)=x;
clear k; clear j;
return;
A.7.2 Program f req
%Digital Signal Processing:A Practitioner's Approach
%Dr.Kaluri Venkata Ranga Rao , [e-mail]
function[m,f]=freq(r);
t=40*pi/180;
b=[1 0 -1];
a=[1 -2*r*cos(t) r*r];
[h,w]=freqz(b,a,180);
f=w/(2*pi);
m=abs(h);
p=angle(h);
return
A.7.3 Program f reqt
%Digital Signal Processing:A Practitioner's Approach
%Dr.Kaluri Venkata Ranga Rao, [e-mail]
function[m,f]=freqt(th);
r=0.9;
t=th*pi/180;
b=[1 0 -1];
a=[1 -2*r*cos(t) r*r];
[h,w]=freqz(b,a,180);
f=w/(2*pi);
m=abs(h);
p=angle(h);
plot(f,m)
grid
return