# design filter with transfer function

1. ## design filter with transfer function

Hi
I want to design a FIR filter with length of 48, also I have the coefficients of num and den.
the length of num and den is 25.
I wanna know is it possible to design the filter with this amount of information?

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2. ## Re: design filter with transfer function

Hi
You are given an IIR filter and now you have to approximate the given IIR filter with an FIR one.

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3. ## Re: design filter with transfer function

Could you pleas describe more? I can't understand what should I do exactly

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4. ## Re: design filter with transfer function

Hi
There are numerous ways to design a FIR filter. One of the way is Windowing method.
In this method you suitably truncate the impulse response values. You may use this method to approximate the given IIR filter.

5. ## Re: design filter with transfer function

unfortunatly I didn't find a matlab code for designing a FIR filter which just needs transfer function and length of filter. I'm so confused :( could you pleas tell me which code is suitable for my design?

6. ## Re: design filter with transfer function

Hi
Sorry for late reply. Actually I was much busy.

You may use impulse function in Matlab to estimate impulse response of an IIR system.

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7. ## Re: design filter with transfer function

@ MHanif,

say there was a 10000 samples input data to a LTI.. After knowing the IIR filter coefficients, i mean the transfer funtion coefficients, how to find the output?? randomly pick a length for the IIR filter coefficients while generating the Impulse response with the help of the coefficients is it what u meant?? but in real world the IIR is infinite rite?? how does it go about this.??

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