freqs
Compute analog filter frequency response values.
Syntax
h = freqs(b,a,w)
[h,w] = freqs(...)
Inputs
- b
- The numerator polynomial coefficients of the filter.
- a
- The denominator polynomial coefficients of the filter.
- w
- The frequencies (in radians/sec) at which the response is computed.
Outputs
- h
- The frequency response values.
- w
- The frequencies (in radians/sec) at which the response is computed.
Example
Verify the cutoff frequency of a fourth order Butterworth low pass analog filter with a 300
radians/sec cutoff
frequency.
b = [0.0, 0.0, 0.0, 0.0, 8.10000e+09];
a = [1.0, 7.83938e+02, 3.07279e+05, 7.05544e+07, 8.10000e+09];
h = freqs(b,a,300);
abs(h)ans = 0.70711