Function Reference: 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);

Demonstration 1

The following code

 B = [1 2];
 A = [1 1];
 w = linspace(0,4,128);
 freqs(B,A,w);

Produces the following figure

Figure 1

Package: signal