Question

transfer function is given as follows. Write down a brief Octave/Matlab code to show is poles omplex plane. m 2 6s? +18s +12 +105 +168 +12

Answer 1

The code to find the poles of the given transfer function amd plot them on zplane is as follow:-

s = tf('s')

H = (6*s^2+18*s+12)/(2*s^3+10*s^2+16*s+12)

P = pole(H)

zplane(P)

When this code is run in the command window step by step the following results appear :-

>> s = tf('s')

s =

s

Continuous-time transfer function.

>> H = (6*s^2+18*s+12)/(2*s^3+10*s^2+16*s+12)

H =

6 s^2 + 18 s + 12
--------------------------
2 s^3 + 10 s^2 + 16 s + 12

Continuous-time transfer function.

>> P = pole(H)

P =

-3.0000 + 0.0000i
-1.0000 + 1.0000i
-1.0000 - 1.0000i

Now to plot the poles in z plane the following command is written

>> zplane(P)

Which gives the following plot

- O X Figure 1 File Edit View O k Insert Tools Desktop Window A Help OE - O 0.5 Imaginary Part of o -0.5 -1.5 0.5 Real Part Type here to search Type here to search o n e A 05:39 PM )) ENG 21-04-20205