Bode Diagramm

[Wilhem]

Hi to eveyrybody,
I m using the latest octave und the package
Control for my University Project but I m not able to display the bode
diagramm on a logarithmic (X) axis. Even semilogx doesn t help.

Do you konw how to visualize bodes diagramms in the right way?
Thank you very much.

Regards
Dave

[Marcio Barbalho]

I didn't quite understand your question. Why is it not working? Are you getting some sort of error?

I'd suggest you built a specif script so it will graph exactly what you want.

Regards

Márcio

[cliff]

Hello Dave: do this
n=[1,0,4];
d=[ 4.0000 14.5245 27.3703 33.2917 27.3703 14.5245 4.0000];
f=logspace(-3,1,300);
w=2*pi*f;
s=sqrt(-1)*w;
close all
semilogx(f,20*log10(abs(polyval(n,s) ./ polyval(d,s)))); grid on; xlabel('Hz'); ylabel('db'); title('Bode plot');