Refs #9791 Edited EnginXCal doc

Code/Mantid/docs/source/algorithms/EnginXCalibrate-v1.rst

@@ -15,10 +15,10 @@ Description
    removed without a notification, should instrument scientists decide to do so.
 
 
-Utilises :ref:`algm-EnginXFocus` which performs a TOF to dSpacing conversion using calibrated pixel positions, focuses the values in dSpacing and then converts them back to TOF. 
-Then calls :ref:`algm-EnginXFitPeaks` which determines peaks through peak function and provides the Difc and ZERO params to the Calibrate algorithm.
-For this algorithm it is the indirect calibration of the sample position that is calibrated and the result of this is returned as Difc and Zero rather than an actual new sample position (hence the reason for 'indirect').
-Allows to correct for deviations in sample position.
+Utilises  :ref:`algm-EnginXFocus` which performs a TOF to dSpacing conversion using calibrated pixel positions, focuses the values in dSpacing and then converts them back to TOF. 
+Then calls  :ref:`algm-EnginXFitPeaks` which through a sequence of peak fits determines a linear relationship between dSpacing and measured TOF values in terms of DIFC and ZERO values and provides the these parameters to the Calibrate algorithm.
+This algorithm provides an indirect calibration of the sample position, that is, a calibration returned in terms of Difc and Zero rather than an actual new sample position (hence the reason for 'indirect').
+
 
 .. categories::