% diagonal matrix to 2nd order filter
% lab2_1.m * mw * 01/06/2007
z = [-j j]; p = [.5 -.25];  % zeros and poles
b = poly(z); a = poly(p);   % numerator and denominator
A = [0 1; -a(3) -a(2)];     % matrix A in drectform II
[V,D] = eig(A);  % eigenvectors and eigenvalues
M = [V(:,1)/V(1,1) V(:,2)/V(1,2)];  % modal matrix
M_1 = inv(M);                       % inverse modal matrix
L = M_1*A*M;                        % diagonal form