Question about transfer function calculations

I have a Transfer function (in Laplace area), and know that the output signal of the system should be a definite value (to be more precise, it's a constant in time area, like 5). How can I calculate the input signal for this output value with MATLAB? in other words: I have the "Transfer function in laplace area" as well as "the output in time area", how can I calculate the input signal using MATLAB?

[Aquatris]

You need to give more information. Does your transfer function has right half plane zeros, what is the order of the tranfer function, does it have same number of poles and zeros?

[Saeed Ahmadzadeh Mahboobi]

No, the Function has just one pole: F=a/(s+b) , whereby a and b are constants and the output should be a constant like c (in time area).

How can I get the input signal for this output ? Thank you

[Aquatris]

If the output is a constant 'c' for a transfer function F(s) = a/(s+b), it means that you are applying a constant input. The gain of F(s) at DC (or 0 Hz, or for constant input) is 'a/b'. So if you apply a constant input 'u = c*b/a', then the output will be 'y = F(0j)*u = a/(0+b)*(c*b/a)=c'.

Hope this helps.