Implementation of Fir Filter Using Efficient Window Function and Its Application in Filtering a Speech Signal

Digital filtering is one of the main fundamental aspect of Digital signal processing, So Digital filters are widely used in many digital signal processing applications. In this paper low-pass FIR filter is implemented using an efficient adjustable window function based on Blackman window function. In this adjustable window function for a fixed length the bandwidth of main lobe and side lobe amplitude can be varied by changing the value of . In the frequency spectrum of window function for a efficiently selected value of , this window provides higher side lobe attenuation comparison to Hamming window and the width of the main-lobe is slightly greater than Hamming window function. In some applications such as FFT, signal processing and measurement where higher side lobe attenuation is required compared to Hamming window this this type of filters can play very significant role. The Blackman window function can also be used for these types of applications but the Blackman window has a wider main lobe width. Designed low-pass FIR filter is used in the speech signal processing application. In this work, firstly speech signal was recorded in wave format after that designed FIR filter applied to this recorded speech signal. Signal comparison between the original speech and filtered speech signal shows that the high frequency component of speech signal has significantly removed by using this FIR low-pass FIR filter. KeywordsBlackman window, FIR filters, FFT, IFFT, Low-pass filter, Speech Signal, Window function http://www.ijeemc.com Volume 1 Issue 1 November 2012