returns new *Signal* with samples of dtype *np_type*

        Parameters
        ----------
        np_type : np.dtype
            new numpy dtye

        Returns
        -------
        signal : Signal
            new *Signal* with the samples of *np_type* dtype

def astype(self, np_type):
        """ returns new *Signal* with samples of dtype *np_type*

        Parameters
        ----------
        np_type : np.dtype
            new numpy dtye

        Returns
        -------
        signal : Signal
            new *Signal* with the samples of *np_type* dtype

        """
        return Signal(
            self.samples.astype(np_type),
            self.timestamps,
            unit=self.unit,
            name=self.name,
            conversion=self.conversion,
            raw=self.raw,
            master_metadata=self.master_metadata,
            display_name=self.display_name,
            attachment=self.attachment,
            stream_sync=self.stream_sync,
            invalidation_bits=self.invalidation_bits,
            source=self.source,
            encoding=self.encoding,
        )