def frequency_from_polarizations(h_plus, h_cross):
    """Return gravitational wave frequency

    Return the gravitation-wave frequency as a function of time
    from the h_plus and h_cross polarizations of the waveform.
    It is 1 bin shorter than the input vectors and the sample times
    are advanced half a bin.

    Parameters
    ----------
    h_plus : TimeSeries
        A PyCBC TimeSeries vector that contains the plus polarization of the
        gravitational waveform.
    h_cross : TimeSeries
        A PyCBC TimeSeries vector that contains the cross polarization of the
        gravitational waveform.

    Returns
    -------
    GWFrequency : TimeSeries
        A TimeSeries containing the gravitational wave frequency as a function
        of time.

    Examples
    --------
    >>> from pycbc.waveform import get_td_waveform, phase_from_polarizations
    >>> hp, hc = get_td_waveform(approximant="TaylorT4", mass1=10, mass2=10,
                         f_lower=30, delta_t=1.0/4096)
    >>> freq = frequency_from_polarizations(hp, hc)

    """
    phase = phase_from_polarizations(h_plus, h_cross)
    freq = numpy.diff(phase) / ( 2 * lal.PI * phase.delta_t )
    start_time = phase.start_time + phase.delta_t / 2
    return TimeSeries(freq.astype(real_same_precision_as(h_plus)),
        delta_t=phase.delta_t, epoch=start_time)
Return gravitational wave frequency

    Return the gravitation-wave frequency as a function of time
    from the h_plus and h_cross polarizations of the waveform.
    It is 1 bin shorter than the input vectors and the sample times
    are advanced half a bin.

    Parameters
    ----------
    h_plus : TimeSeries
        A PyCBC TimeSeries vector that contains the plus polarization of the
        gravitational waveform.
    h_cross : TimeSeries
        A PyCBC TimeSeries vector that contains the cross polarization of the
        gravitational waveform.

    Returns
    -------
    GWFrequency : TimeSeries
        A TimeSeries containing the gravitational wave frequency as a function
        of time.

    Examples
    --------
    >>> from pycbc.waveform import get_td_waveform, phase_from_polarizations
    >>> hp, hc = get_td_waveform(approximant="TaylorT4", mass1=10, mass2=10,
                         f_lower=30, delta_t=1.0/4096)
    >>> freq = frequency_from_polarizations(hp, hc)