How do I create a transfer function using the zp2tf function with following poles and zeros

Zeros = 1 -1 0.5+2i 0.5-2i poles = -0.3 3 0.2+7i 0.2-7i with a gain k of 1 and i=sqrt(-1) can seem to get the transfer function just keep getting errors could someone help with correct code thanks

[Paul]

Show your code along the complete error message.

Answer 1

[Sam Chak]

Hi @Matthew

I didn't know what code you have tried. But you just need to specify the zeros, poles, and the gain correctly, and use the zpk() command, followed by the tf() commant.

z = [1 -1 0.5+2i 0.5-2i];   % zeros
p = [-0.3 3 0.2+7i 0.2-7i]; % poles
k = 1;                      % gain
G = zpk(z,p,k)

G =
 
     (s-1) (s+1) (s^2 - s + 4.25)
  ----------------------------------
  (s+0.3) (s-3) (s^2 - 0.4s + 49.04)
 
Continuous-time zero/pole/gain model.

G = tf(G)

G =
 
       s^4 - s^3 + 3.25 s^2 + s - 4.25
  -----------------------------------------
  s^4 - 3.1 s^3 + 49.22 s^2 - 132 s - 44.14
 
Continuous-time transfer function.