def resample_signal(self, data_frame):
        """
            Convenience method for frequency conversion and resampling of data frame. 
            Object must have a DatetimeIndex. After re-sampling, this methods interpolate the time magnitude sum 
            acceleration values and the x,y,z values of the data frame acceleration

            :param data_frame: the data frame to resample
            :param str sampling_frequency: the sampling frequency. Default is 100Hz, as recommended by the author of the pilot study [1]
        """
        new_freq = np.round(1 / self.sampling_frequency, decimals=6)
        df_resampled = data_frame.resample(str(new_freq) + 'S').mean()

        # f = interpolate.interp1d(data_frame.td, data_frame.mag_sum_acc)
        
        # new_timestamp = np.arange(data_frame.td[0], data_frame.td[-1], 1.0 / self.sampling_frequency)
        # df_resampled.mag_sum_acc = f(new_timestamp)
        
        logging.debug("resample signal")
        df_resampled = df_resampled.interpolate(method='linear')
        get_sampling_rate_from_timestamp(df_resampled)
        
        # df_resampled['td'] = df_resampled.index - df_resampled.index[0]
        
        return df_resampled
Convenience method for frequency conversion and resampling of data frame. 
            Object must have a DatetimeIndex. After re-sampling, this methods interpolate the time magnitude sum 
            acceleration values and the x,y,z values of the data frame acceleration

            :param data_frame: the data frame to resample
            :param str sampling_frequency: the sampling frequency. Default is 100Hz, as recommended by the author of the pilot study [1]