Signal Toolkit - freqs

Function File: h = freqs (b, a, w)

Function File: freqs (b, a, w)

Compute the s-plane frequency response of the IIR filter B(s)/A(s) as H = polyval(B,j*W)./polyval(A,j*W). If called with no output argument, a plot of magnitude and phase are displayed.

Example:

 b = [1 2]; a = [1 1];
 w = linspace (0, 4, 128);
 freqs (b, a, w);