function [g,w] = gain(num,den)% Computes the gain function in dB of a % transfer function at 256 equally spaced points % on the unit circle% Numerator coefficients are in vector num% Denominator coefficients are in vector den% Frequency values are returned in vector w% Gain values are returned in vector gw = 0:pi/255:pi;h = freqz(num,den,w);g = 20*log10(abs(h));