% klh.m - lowpass/highpass FIR filter design using Kaiser window.%% h = klh(s, fs, fpass, fstop, Apass, Astop)%% s = 1, -1 = lowpass, highpass% dlh(s, wc, N) = ideal lowpass/highpass FIR filterfunction h = klh(s, fs, fpass, fstop, Apass, Astop)fc = (fpass + fstop) / 2;  wc = 2 * pi * fc / fs;Df = s * (fstop - fpass);  DF = Df / fs;dpass = (10^(Apass/20) - 1) / (10^(Apass/20) + 1);dstop = 10^(-Astop/20);d = min(dpass, dstop);  A = -20 * log10(d);[alpha, N] = kparm(DF, A);h = dlh(s, wc, N) .* kwind(alpha, N);