% dlh.m - ideal lowpass/highpass FIR filter%% h = dlh(s, wc, N) = row vector%% s = 1, -1 = lowpass, highpass% N = 2M+1 = filter length (odd)% wc = cutoff frequency in [rads/sample]function h = dlh(s, wc, N)M = (N-1)/2;for k = -M:M,    if k == 0,        h(k+M+1) = (1-s) / 2 + s * wc / pi;    else        h(k+M+1) = s * sin(wc * k) / (pi * k);    endend