[Scilab-users] Problems with Bode and Bode asymptotic

[Emmanuel Delaleau]

I don't succeed in using the Bode plots facilities. (See script below).

- on fig 1 and 2 one sees a shift between the true and the asymptotic 
Bode plot

_ on fig 3 one sees a strange plot corresponding to the second argument 
of frequency bounds.

Do you have any idea ?

Thank in advance.

Emmanuel

//-------------------------------------------------------------------------------------------------------------

//
xdel(winsid());
f1 = 100;
w1 = 2*%pi*f1;
tau1 = 1/w1;
H1 = 10/(1 + tau1*%s); // order 1 system
S1 = syslin('c',H1);
scf(1);
bode(S1);//,[0.001,10000]);
bode_asymp(S1);
xtitle('Order one');
//xs2pdf(1,'order1bode');

m = .125;//sqrt(2)/4;
wn = w1;
H2 = 10/(1 + 2*m*%s/wn + %s^2/wn^2); // order 2 system
S2 = syslin('c',H2);

scf(2);
bode(S2,[.01,1e4]);
bode_asymp(S2);
xtitle('Order two');
//xs2pdf(2,'order2bode');


scf(3);
bode(S1,[0.01,1000]);