function mag = zinc(f,m,n)% mag = zinc(f,m=64,n=1)	Calculate the magnitude response% of a cascade of n mth-order comb filters at frequencies f.if nargin<3	n = 1;    if nargin<2	    m = 64;    endendmag = ones(size(f));nonzero = mod(f,1) ~=0;mag = abs( sinc(m*f) ./ sinc(f) ).^n;