sdir2cas.m

西交大刘树棠写的《数字信号处理》那本书的所有源代码

function [C,B,A]=sdir2cas(b,a);
Na=length(a)-1;Nb=length(b)-1;
b0=b(1);b=b/b0;
a0=a(1);a=a/a0;
C=b0/a0;
P=cplxpair(roots(a));K=floor(Na/2);
if K*2==Na  
A=zeros(K,3);
for n=1:2:Na
Arow=P(n:1:n+1,:);
Arow=poly(Arow);
A(fix((n+1)/2),:)=real(Arow);
end
elseif Na==1
A=[0  real(poly(P))];
else 
A=zeros(K+1,3);
for n=1:2:2*K
    Arow=P(n:1:n+1,:);
    Arow=poly(Arow);
    A(fix((n+1)/2),:)=real(Arow);
    end
    A(K+1,:)=[0  real(poly(P(Na)))];
end
Z=cplxpair(roots(b));K=floor(Nb/2);
if Nb==0 
B=[0  0  poly(Z)];
elseif K*2==Nb 
B=zeros(K,3);
for n=1:2:Nb
    Brow=Z(n:1:n+1,:);
    Brow=poly(Brow);
    B(fix((n+1)/2),:)=real(Brow);
 end
 elseif Nb==1
B=[0  real(poly(Z))];
else
B=zeros(K+1,3);
for n=1:2:2*K
    Brow=Z(n:1:n+1,:);
    Brow=poly(Brow);
end
B(K+1,:)=[0  real(poly(Z(Nb)))];
end