The FIR filter was designed using Windowing method. The method multiplied window function to desired impulse response to obtain h(n). Window function had to be selected by an user and then other input parameters such as attenuations and frequencies had to be given. Out of five known window function, Hanning window function was used in the experiment. The length of the impulse response was equivalent to the order of filter. After finding h(n), Z- transform was used to find transfer function H(z).
Window functions are preferable because they allow different window functions
ReplyDeletewhich can be used as per the design specifications of filter we can choose the different window function depending on the attenuation in stopband and passband.
Different window functions are used depending upon stop band attenuation.
DeleteRectangular window is not generally preferred.
ReplyDeleteYes, rectangular window function has lowest attenuation in stop band.
DeleteBlackmann window is the best for designing higher order precise filters.
ReplyDeleteDue its higher attenuation in stop band
DeleteFIR filter is designed by truncating infinite samples of hd[n] by using window function.
ReplyDeleteYes. It truncates hd[n] by using window function.
DeleteRectangular window function has As=21db which is very small compared to other window functions.
ReplyDeleteWhich makes it less preferred window function.
DeleteAs parameter should be as high as possible. Blackman filter has As=74 which is highest among other filters and so it has high efficiency.
ReplyDeleteWe can find the approximate window length by equating the main lobe width with the transition band of the desired filter.
ReplyDelete