How can I extract numerator and denominator as polynomials from a transfer function?

I'm am having some stupid trouble with transfer functions.

If I have to write the tf:

              s^2 + 2 s
G(s) =  ---------------------
        s^3 - 2 s^2 + 4 s + 1

I could write: G=tf([2 1 0],[1 -2 4 1])

But now, I would like to extract numerator and denominator as array. If I write: [Num, Den]=tfdata(G) the programm gives me them as cells

Num =

cell

    [1×4 double]

Den =

cell

    [1×4 double]

How can I take numerator and denominator as arrays? I would like to receive

Num =

    [2 1 0]

Den =

    [1 -2 4 1]

Thank you

[Vaibhav Singh]

Can someone help me please.. everytime I write the terms for s^2 inside transfer block properties it shows me the format..num(s)/den(s) ..

[Walter Roberson]

Is that a question about a Simulink block?

[Petr Danielka]

If you make the "Transfer Function" block bigger, it will show properly

Answer 1

[Thiago Barreto]

Just do this:

G = tf([2 1 0],[1 -2 4 1]);
[num den] = tfdata(G, 'v');

num =
     0     2     1     0
den =
     1    -2     4     1

[Fabricio Arturo Balboa Cavazos]

I needed to extract que coeficients to use the Jury criteria, thanks a lot man.

Answer 2

[Bill Tubbs]

The answer is good but what if I want to go one step further?

What if I want A(s) and B(s) where G(s) = B(s)/A(s)?

This seems to work, is this the right way to do it?

>> B = tf(num,1)

B =
 
  2 s^2 + s
 
Continuous-time transfer function.

>> A = tf(den,1)

A =
 
  s^3 - 2 s^2 + 4 s + 1
 
Continuous-time transfer function.

[Walter Roberson]

That looks ok