The objective of this experiment was to design digital filter using windowing technique and study the spectrum of filter.
This experiment was implemented in two stages:
1.C code: in the first part of the experiment we calculated impulse response h(n) of the filter by multiplying desired impulse response hd(n) with window funtion W(n). Input specifications as mentioned in the lab manual were entered and the opuput of the code was h(n). This impulse response obtained was noted down and used in stage 2.
2. Scilab code: The values obtained from stage one were used to find magnitude and phase plot for the required impulse response.
Thus FIR filter was designed by truncating infinite samples of hd(n) using windowing method. The implulse response of FIR filter obtained was symmetric in nature. Hence its phase spectrum was linear(i.e phase response varies linearly with frequency)
https://drive.google.com/open?id=0B8Ks3rz0S_nzbXZXTU8zMWp4OG8
This experiment was implemented in two stages:
1.C code: in the first part of the experiment we calculated impulse response h(n) of the filter by multiplying desired impulse response hd(n) with window funtion W(n). Input specifications as mentioned in the lab manual were entered and the opuput of the code was h(n). This impulse response obtained was noted down and used in stage 2.
2. Scilab code: The values obtained from stage one were used to find magnitude and phase plot for the required impulse response.
Thus FIR filter was designed by truncating infinite samples of hd(n) using windowing method. The implulse response of FIR filter obtained was symmetric in nature. Hence its phase spectrum was linear(i.e phase response varies linearly with frequency)
https://drive.google.com/open?id=0B8Ks3rz0S_nzbXZXTU8zMWp4OG8
Nice explanation.
ReplyDeleteNice explanation.
ReplyDeleteBlackman window is the best since it has the highest attenuation in the stop band
ReplyDeleteYes.. But unfortunately Pranav I didn't get to see its spectrum. My input specs were for hamming window.
ReplyDeleteThe value of As of window function should be higher than that of given filter.
ReplyDeleteThe magnitude of lobes of blackman function were a lot smaller than that of rectangular window function
ReplyDeleteThe longer the signal, smaller is the width of the main lobe. With reduced main lobe, the transition region reduces and hence the filter becomes more stable.
ReplyDeleteThere are primarily 5 window functions - Rectangular, Bartlett, Hamming, Hanning and Blackman. Out of which Blackamn is best due to high attenuation
ReplyDelete