python-scipyHow do I use the Scipy freqz function in Python?

The scipy.signal.freqz function in Python is used to compute the frequency response of a digital filter. This function takes two arguments: a numerator and denominator polynomial coefficients of a digital filter.

Example code

from scipy.signal import freqz
b = [1, -2, 0.5]
a = [1, 0, 0.3]
w, h = freqz(b, a)

The output of the above code is two arrays w and h which contain the frequency and corresponding complex frequency response of the filter, respectively.

Code explanation

1. from scipy.signal import freqz - imports the freqz function from the scipy.signal module
2. b = [1, -2, 0.5] - defines the numerator polynomial coefficients of the filter
3. a = [1, 0, 0.3] - defines the denominator polynomial coefficients of the filter
4. w, h = freqz(b, a) - computes the frequency response of the filter using the freqz function

Helpful links

• Scipy freqz documentation
• Digital filter design tutorial

Edit this code on GitHub