docs: def get_pulse_s(self):
          """Get pulse duration in seconds, for pulsed measurements."""
          
          try:
              dwelltime = self.ppg.dwelltime.mean
              beam_on = self.ppg.beam_on.mean
          except AttributeError:
              raise AttributeError("Missing logged ppg parameter: dwelltime "+\
                      "or beam_on")
          return dwelltime*beam_on/1000.