def __init__(self, data, sampling=<NUM_LIT:1.>, ar_order=None, ma_order=None,<EOL>lag=-<NUM_LIT:1>, NFFT=None, detrend=None, scale_by_freq=True):
super(ParametricSpectrum, self).__init__(data, sampling=sampling,<EOL>NFFT=NFFT,<EOL>scale_by_freq=scale_by_freq,<EOL>detrend=detrend)<EOL>if ar_order is None and ma_order is None:<EOL><INDENT>raise errors.SpectrumARMAError<EOL><DEDENT>self.__ar_order = ar_order<EOL>self.__ma_order = ma_order<EOL>self.ar_order = ar_order<EOL>self.ma_order = ma_order<EOL>self.lag = lag<EOL>self.__ar = None<EOL>self.__ma = None<EOL>self.__reflection = None<EOL>self.__rho = None<EOL>
**Constructor**

        See the class documentation for the parameters.

        .. rubric:: Additional attributes to those inherited
            from :class:`Spectrum`:

        * :attr:`ar_order`, the ar order of the PSD estimates
        * :attr:`ma_order`, the ar order of the PSD estimates