code: def amplitude(self, caldb, calv, atten=0):
          
          amp = (10 ** (float(self._intensity+atten-caldb)/20)*calv)
          return amp
docs: Calculates the voltage amplitude for this stimulus, using
          internal intensity value and the given reference intensity & voltage
  
          :param caldb: calibration intensity in dbSPL
          :type caldb: float
          :param calv: calibration voltage that was used to record the intensity provided
          :type calv: float