matlab

clc;
clear;

x=logspace(-2,2,100);

%h1=[1 -2 3];        stabilny
%h2=[1 2 3];

%h1=[1];             oscylator
%h2=[1 0 2];


%h1=[1 -2 3];        oscylator
%h2=[1 0 2];


%h1=[1 2];           stabilny
%h2=[1 1];


%h1=[1 -1];          stabilny
%h2=[1 1];


%h1=[2 3];           stabilny
%h2=[1 4 4];


%h1=[1 2 2 0 2];     niestabilny
%h2=[1 -2 4 1];


%h1=[1 1];           %stabilny
%h2=[1 3 1];


%h1=[1];             %stabilny
%h2=[1 8 15];


%h1=[1];             niestabilny
%h2=[1 6 -7];


h1=[1 6 8];
h2=[1 2 3];
h3=[1 -2 -8];
h5=[1 -6 8];
h7=[1 2 -8];

s=i.*x;

roots(h2)

Ha1=polyval(h1,s);
Ha2=polyval(h2,s);
Ha3=polyval(h3,s);
Ha5=polyval(h5,s);
Ha7=polyval(h7,s);


H1=Ha1./Ha2;
H2=Ha3./Ha2;
H3=Ha5./Ha2;
H4=Ha7./Ha2;

figure(1)
loglog(x,abs(H1));

hold on;
loglog(x,abs(H2));
loglog(x,abs(H3));
loglog(x,abs(H4));
grid;
hold off;

figure(2);

semilogx(x,angle(H1));
hold on;
semilogx(x,angle(H2));
semilogx(x,angle(H3));
semilogx(x,angle(H4));
hold off;
grid;