def impedance_filter(c):
    num = c[0]
    den = c[1]

    summed = [a + b for a, b in zip(den, num)]
    subbed = [a - b for a, b in zip(den, num)]

    norm = 1 / subbed[0]
    summed = [i * norm for i in summed]
    subbed = [i * norm for i in subbed]

    return [summed, subbed]