MATLAB and C Programs - Digital Signal Processing: A Practitioner's Approach - page 142

clear;close;
n=6;rdb=0.4;wn=0.4;
[b,a]=cheby1(n,rdb,wn);
%[b,a]=butter(n,wn);
N=360;
fn=linspace(0,0.5,N);
sysd=tf(b,a,1); hk=impulse(sysd);
m=abs(freqz(b,a,N));
phi=angle(freqz(b,a,N))*180/pi;
nmax=length(fn); n1=round(wn*nmax*1.1);
line_1=ones(size(fn(1:n1)))*0.92;
line_2=ones(size(fn(1:n1)))*1.02; part_1=fn(1: n1);
subplot(211);plot(fn,m,part_1,line_1,part_1,line_2);grid;
print -depsc f3_1
%temp1=abs(roots(a)) ;temp=angle(roots(a));
% [theta,i]=sort(temp);r=temp1(i);pause;
%subplot(111) ;polar(theta,r, 'o') ;grid;
%subplot(212) ;plot(fn,phi,fn,phi_new) ;grid;
%[xp, yp]=ginput (1);
text(xp,yp,'O

< --- Non-linear Phase of IIR Filter ')
%[xp,yp]=ginput(1);
text(xp,yp,'O < --- Linear Phase of FIR filter ')

%print -depsc f3_8

A.3.2 Program f 3_1a

%Digital Signal Processing:A Practitioner's Approach
%Dr.Kaluri Venkata Ranga Rao, [e-mail]
%Generates figure 3.2

clear;clg
k=1:200;f=0.02;x=sin(2*pi*f*k)+0.2*rand(size(k));
subplot(211);stem(k,x);grid

A.3.3 Program f 3_2

%Digital Signal Processing:A Practitioner's Approach
%Dr.Kaluri Venkata Ranga Rao, [e-mail]
%Generates figure 3.9

clear;close;
xk=1;xk1=0;
for i=1:20
xk2=xk1;xk1=xk;xk=1.8*xk1-xk2;