Transfer Function of a Filter

[nigeltorque]

Hi everybody

i need to create a filter from a transfer function. I get the transfer function from a frequency response of a DUT and then i have to implement it. I try to explain better: i plot the frequency response of my DUT, i make a fit of the response and get a polynomial equation that describe that curve, then i inverse the transfer function plot and and put the new polynomial equation in this form: 1 / (a0 + a1 X + a2 X^2 + ...). Now i think i have to go from X to frequency domain and then i can implement the transfer function to obtain a filter to filtering a waveform.

Is it correct?? Do you have any other idea??

I have the Digital Filter Toolkit and The Control e Simulation Toolkit.

Please let me know if you have an advice

Thank you

[nigeltorque]

Well i mean..

is it possible to build a filter that has a magnitude/frequency response  which follows the course of a curve (a frequency response) that has a well know formula?? 

Thank You

[AntonisV]

Hello Nigeltorque,

have you taken a look at the following example?

Filter and Frequency Response

http://zone.ni.com/devzone/cda/epd/p/id/3249

Does this respond to your question?