iir_theory.py 文件源码

def freqz_(sys, w, dt=8e-9):
    """
    This function computes the frequency response of a zpk system at an
    array of frequencies.

    It loosely mimicks 'scipy.signal.frequresp'.

    Parameters
    ----------
    system: (zeros, poles, k)
        zeros and poles both in rad/s, k is the actual coefficient, not DC gain
    w: np.array
        frequencies in rad/s
    dt: sampling time

    Returns
    -------
    np.array(..., dtype=np.complex) with the response
    """
    z, p, k = sys
    b, a = sig.zpk2tf(z, p, k)
    _, h = sig.freqz(b, a, worN=w*dt)
    return h