Friday, 22 April 2016

FIR Filter design using Windowing method

FIR filters can be designed to be linear phase by making the coefficients symmetric. They are stable as compared to other filters. There are many ways to design these filters. Here, I have designed the filter using Windowing method. The coding for this was done in C and SCILAB to obtain the Magnitude and Phase plots. C programming was used to obtain the h[n] values of the signal, while SCILAB was used to plot the graphs
Initially, I was a bit confused about how to plot the phase plot graph. It took me a few weeks to understand the actual working of the filter, which later on paved the way for me to write the code. The phase plot shows desired linear characteristics.

Go to the link below to view the codes for obtaining h[n] values of high pass, low pass, and band pass filters and also to plot the magnitude and phase plot,
https://drive.google.com/open?id=0B8OWu2Drhsp0YjdoODVGQ1dQakE

6 comments:

  1. could have mentioned that filter design and accuracy depends on As

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  2. which window function is better?

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    Replies
    1. In order to obtain smaller transition region (i.e max stability), Blackman window function will be better, since the length of the signal increases in it, and increased signal length reduces the transition region

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    2. Comparison of window function is given in every reference book of DSP. You need to find time and sit in library. Our library has good no of reference books.

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  3. Greater is the value of As, better is the window function.

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