A = [0 1 0 0
    -4 -4 0 0
    0 0 0 1
    6 0 0 0];
B=[0 3 0 -1]';
C=eye(4);
D=[0 0 0 0]';

tal = 0.2;
G=tf(1,[tal,1]);
%pre_filtro = G*G*G*G;
pre_filtro = series(series(tf(1,[tal 1]),tf(1,[tal 1])),series(tf(1,[tal 1]),tf(1,[tal 1])));
[numpf,denpf]=tfdata(pre_filtro,'v');
[Apf,Bpf,Cpf,Dpf]=tf2ss(numpf,denpf)
Cpf=eye(4)*625;
Dpf=[0 0 0 0]';

AA =[
     0     3     0    -1
     3     0    -1     -4
     0     0    -4   14
     0     0    14     0];

CC= inv(AA)*[0 0 2.24 2.24*6.24]';
CC=CC';

N1=(CC*A*A)*B;
mat1=(CC*A*A)*A/N1;


tal = 20;
mf = series(series(tf(1,[tal 1]),tf(1,[tal 1])),tf(1,[tal 1]));
[num,den]=tfdata(mf,'v');