compensating for frequency drift of a reference energy source in an ft interferometer based spectrometer instrument may include obtaining data representing a reference interferogram collected in response to a trigger signal having been generated in dependence on the emission frequency of the reference energy source , and subsequently obtaining data representing a target interferogram recorded by the ft interferometer in response to a trigger signal also having been generated in dependence on the emission frequency of the reference energy source in the same manner . the method may further include comparing the obtained data to determine a phase shift between the interferograms in a window in at least one region away from center - burst , and generating a mathematical transform dependent on the determined shift to be subsequently applied to generate data representing a frequency stabilized interferogram of an unknown sample recorded by the ft interferometer .