Pole zero plot and frequancy response of a system in MATLAB

20 vues (au cours des 30 derniers jours)
Muhammad Ali
Muhammad Ali le 29 Oct 2020
Commenté : Ameer Hamza le 30 Oct 2020
I have the following system:
I am required to find its frequency response using freqresp() function and find its magnitude response over the range 0 ≤ ω ≤ 20 in steps of 0.01. I am also required to plot its magnitude response and compare the results with its pole zero plot. I wrote following code for this in matlab but don't know whats the problem with this. The code is running without error but I think the plot of magnitude respnse is wrong. Kindly help me about these questions.
w = 0:0.01:20;
num = [3 4];
den = [1 5 8 4];
zeros = roots(num);
poles = roots(den);
H = tf (num,den);
%pzmap(H)
%grid on
H1 = freqresp(H,w);
H2 = squeeze(H1);
plot(w,abs(H2))
xlabel('w');
ylabel('freq response');

Réponses (2)

Ameer Hamza
Ameer Hamza le 29 Oct 2020
It looks strange because the frequency response is usually plotted on logarithmic axes. Replace the line
plot(w,abs(H2))
with
loglog(w,abs(H2))
  2 commentaires
Muhammad Ali
Muhammad Ali le 29 Oct 2020
Now I am getting this.
But how would know that this plot correct? and whats the of this plot with pole zero plot?
Ameer Hamza
Ameer Hamza le 29 Oct 2020
You can use bode() function to see if this is correct.

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Muhammad Ali
Muhammad Ali le 30 Oct 2020
Yeah thats correct now. Thank you for your kind help.

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