def ABCDFrequencyList_to_HFrequencyList(ABCD_frequency_list):
    """ Converts ABCD parameters into h-parameters. ABCD-parameters should be in the form [[f,A,B,C,D],...]
    Returns data in the form
    [[f,h11,h12,h21,h22],...]
    """
    h_frequency_list=[]
    for row in ABCD_frequency_list[:]:
        [frequency,A,B,C,D]=row
        h11=B/D
        h12=(A*D-B*C)/D
        h21=-1/D
        h22=C/D
        h_frequency_list.append([frequency,h11,h12,h21,h22])
    return h_frequency_list