# Digital Signal Processing Using MATLAB

### John Proakis (view profile)

• 1 file
• 4.38298

21 Aug 2002 (Updated )

Companion Software

dir2par(b,a);
```function [C,B,A] = dir2par(b,a);

% DIRECT-form to PARALLEL-form conversion

% --------------------------------------

% [C,B,A] = dir2par(b,a)

%  C = Polynomial part when length(b) >= length(a)

%  B = K by 2 matrix of real coefficients containing bk's

%  A = K by 3 matrix of real coefficients containing ak's

%  b = numerator polynomial coefficients of DIRECT form

%  a = denominator polynomial coefficients of DIRECT form

%

M = length(b); N = length(a);

[r1,p1,C] = residuez(b,a);

p = cplxpair(p1,10000000*eps);

I = cplxcomp(p1,p);

r = r1(I);

K = floor(N/2); B = zeros(K,2); A = zeros(K,3);

if K*2 == N; %N even, order of A(z) odd, one factor is first order

for i=1:2:N-2

Brow = r(i:1:i+1,:);

Arow = p(i:1:i+1,:);

[Brow,Arow] = residuez(Brow,Arow,[]);

B(fix((i+1)/2),:) = real(Brow');

A(fix((i+1)/2),:) = real(Arow');

end

[Brow,Arow] = residuez(r(N-1),p(N-1),[]);

B(K,:) = [real(Brow') 0]; A(K,:) = [real(Arow') 0];

else

for i=1:2:N-1

Brow = r(i:1:i+1,:);

Arow = p(i:1:i+1,:);

[Brow,Arow] = residuez(Brow,Arow,[]);

B(fix((i+1)/2),:) = real(Brow');

A(fix((i+1)/2),:) = real(Arow');

end

end

```