Symbolic tool box - Equation in desired form

Hi,

How can I tell matlab to give me the result in desired form.

I'm using symbolic tool box.

For example, I got following transfer function from the symbolic tool box calculation

G=D*R*1/(C*L*R*s^2+L*s+R)

but I want matlab to represent the same function as follows

G=G_s*1/(1+s/(Qω_c )+(s/ω_c )^2 )

Where

 G_s=D
ω_c=1/√LC
Q=R*√(C/L)

Also find the attached.

Thanks.

[Stephan]

Jochen, mit der Frage kann niemand etwas anfangen. Welche Gleichung? Was hast Du bisher versucht? Bitte teile Deinen Code mit uns. Erzähle uns auch etwas über Dein Ziel. Was möchtest Du erreichen?

[Jochen Baier]

Thanks for the suggestion. Please see the question again.

[Walter Roberson]

You can do part of that using subs(), such as

subs(G, D*R, sym('G_s'))

However, you will have difficulty getting ω or √ symbols.

[Jochen Baier]

Thanks for the answer.

But, I want matlab to give me G_s, w_c & Q.

What I have showed you is a simple 2nd order transfer function. I want to know these values for 3rd, 4th order transfer function which will have other constants as well.

Let me know.

[Walter Roberson]

Some of that looks like partial fraction analysis. The rest of it looks like using children() to extract sub-expressions.

[Jochen Baier]

Thanks, I'll try this.