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FIR Filter Design : Windowing Method

FIR Filter Design : Windowing Method 

FIR Filters being inherently stable can be designed to have a linear phase. Their is a great flexibility in shaping their magnitude response and these are easy and convenient to implement. This being said,  Digital FIR filters cannot be derived from from analog filters as analog filters cannot have a finite impulse response.  

In this experiment, a causal linear phase FIR Filter was designed by multiplying an ideal filter that has an infinite duration impulse response (IIR) by a finite duration window function. The Scilab code was written for calculating the parameters using Hanning Window Function. The window shape affects the width of the transition band and stop band attenuation while window duration affects the transition bandwidth only. Having given the values of parameters like attenuation in pass band and stop band and frequencies as input, the response of filter was plotted. 

There are much less ripples for the hanning window than the rectangular window, but the transition width is higher.  

Comments

  1. $oM€$h26 April 2017 at 07:02

    FIR requires large amount of memory though!

    ReplyDelete
  2. Amol26 April 2017 at 19:21

    As we go from rectangular window function to hanning window, we get smoother response which reduces Gibbs phenomenon.

    ReplyDelete

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