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# scipy.signal.freqs

`scipy.signal.``freqs`(b, a, worN=None, plot=None)

  Compute frequency response of analog filter.

  Given the numerator (b) and denominator (a) of a filter compute its frequency response.

  > b[0]*(jw)**(nb-1) + b[1]*(jw)**(nb-2) + ... + b[nb-1]

  H(w) = ——————————————————–
    a[0]*(jw)**(na-1) + a[1]*(jw)**(na-2) + ... + a[na-1]

  Parameters: | b : ndarray numerator of a linear filter a : ndarray numerator of a linear filter worN : {None, int}, optional If None, then compute at 200 frequencies around the interesting parts of the response curve (determined by pole-zero locations). If a single integer, the compute at that many frequencies. Otherwise, compute the response at frequencies given in worN.
  Returns: | w : ndarray The frequencies at which h was computed. h : ndarray The frequency response.

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