features.py 文件源码

def homomorphic_envelope(x, fs=1000, f_LPF=8, order=3):
    """
    Computes the homomorphic envelope of x

    Args:
        x : array
        fs : float
            Sampling frequency. Defaults to 1000 Hz
        f_LPF : float
            Lowpass frequency, has to be f_LPF < fs/2. Defaults to 8 Hz
    Returns:
        time : numpy array
    """
    b, a = butter(order, 2 * f_LPF / fs, 'low')
    he = np.exp(filtfilt(b, a, np.log(np.abs(hilbert(x)))))
    return he