Sep 11, 2009 #1 M musicguy Junior Member level 3 Joined Aug 9, 2009 Messages 30 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,286 Activity points 1,462 b = fir1(n,Wn) if i am using hamming window FIR filter, what is the formula for calculating 'n'.