www.pudn.com > 现代信号处理教程.rar > exa070802.m

%----------------------------------------------------------------------------------- 
% exa070802.m    for example 7.8.2 ,fig7.8.1 and fig 7.8.2 
% to explain how to design a biorthogonal FB by spectral factorisation.; 
% p.mat: From program exa060301.m 
%----------------------------------------------------------------------------------- 
clear all; 
load p; 
 
N0=512;Fs=1; 
a=1; 
A=zeros(length(p),1); 
A(1)=1; 
[Z,P,K]=tf2zp(p,A') 
 
%-------------------------------------------------------------------------------- 
% Next loop is for MATLAB 5.3 
%   for i=9:18 
%       Z(i)=-1; 
%   end 
%   z0=[Z(1),Z(2),Z(7),Z(8),Z(9),Z(10),Z(11),Z(12),Z(13)] 
%   z1=[Z(3),Z(4),Z(5),Z(6),Z(14),Z(15),Z(16),Z(17),Z(18)] 
%-------------------------------------------------------------------------------- 
 
for i=5:14 
    Z(i)=-1; 
end 
  
z0=[Z(1),Z(2),Z(5),Z(6),Z(7),Z(8),Z(9),Z(17),Z(18)] 
z1=[Z(3),Z(4),Z(10),Z(11),Z(12),Z(13),Z(14),Z(15),Z(16)] 
temp0=1; 
temp1=1; 
for i=1:9 
    temp0=(-z0(i))*temp0; 
    temp1=(-z1(i))*temp1; 
end 
if imag(temp0)<0.0001 
   temp0=real(temp0); 
end 
if imag(temp1)<0.0001 
   temp1=real(temp1); 
end 
K0=sqrt(K/temp0); 
K1=sqrt(K/temp1); 
 
 
l0=length(z0); 
l1=length(z1); 
P0=zeros(l0,1); 
P1=zeros(l1,1); 
[h0,P0]=zp2tf(z0',P0,K0); 
[h11,P1]=zp2tf(z1',P1,K1); 
h1=qmf(h11,1); 
 
 
figure(1) 
subplot(221) 
stem(h0);grid; 
subplot(222) 
zplane(h0,1);grid; 
subplot(223) 
stem(h1);grid; 
subplot(224) 
zplane(h1,1);grid; 
 
figure(2) 
[H0,w]= freqz(h0,a,N0,Fs); 
[H1,w]= freqz(h1,a,N0,Fs); 
absH0=abs(H0); 
absH1=abs(H1); 
subplot(224) 
plot(w,absH0,'k-',w,absH1,'b-');grid;