def getSignalHeader(self, chn):
        """
        Returns the  header of one signal as  dicts

        Parameters
        ----------
        None
        """
        return {'label': self.getLabel(chn),
                'dimension': self.getPhysicalDimension(chn),
                                 'sample_rate': self.getSampleFrequency(chn),
                'physical_max':self.getPhysicalMaximum(chn),
                'physical_min': self.getPhysicalMinimum(chn),
                'digital_max': self.getDigitalMaximum(chn),
                'digital_min': self.getDigitalMinimum(chn),
                'prefilter':self.getPrefilter(chn),
                'transducer': self.getTransducer(chn)}
Returns the  header of one signal as  dicts

        Parameters
        ----------
        None