writing transfer functions in matlab

Hi, I want to write a transfer function in matlab. I know we usually write in the following way

trans = tf([1 0 0], [1 0 1]);

This gives something as a function of 's'.

what if i wanted to write an equation that was a function of 's+x', where x is a constant. So instead of H(s), i want to write a function and evaluate at values of say H(s+5).

thanks

[rupam mahapatra]

Write a MATLAB program to determine the partial fraction expansion of a rational z-transform. Using this program

determine the partial-fraction expansion of G(z).

Answer 1

[Thomas]

The documentation has good examples on how to write transfer functions:

http://www.mathworks.com/help/toolbox/control/ref/tf.html

[aaa]

Hi, yes, i have looked through this documentation, but was not able to find what i wanted.

Any helps with implementation would be great

[Thomas]

is this what you want:

trans=tf([1 5],[1])

trans =

s + 5

[aaa]

thanks for your reply.

that is not quite what i am looking for. that method just gives H(s) still. I would like to implement something that is in the form of H(s+5)

Answer 2

[Arkadiy Turevskiy]

Do you want to see the resulting expression as a function of (s+x), or do you just want to write an equation as function of (s+x)? If it is the latter you could do this:

>> arg=tf('s')+5

arg =

s + 5

Continuous-time transfer function.

>> h=1/(arg+3)

h =

    1
  -----
  s + 8

Continuous-time transfer function.

>> arg=tf('s')+10

arg =

s + 10

Continuous-time transfer function.

>> h=1/(arg+3)

h =

    1
  ------
  s + 13

Continuous-time transfer function.

HTH. Arkadiy

Answer 3

[Savan Prajapati]

num = 100

den = [1,14,10]

sys = tf(num,den)

printsys(num,den)