Abstract: The apparatus and method of the invention are applied to the generation of alternating sample, dark, reference and dark beams for direction of the sample and reference beams into an integrating sphere which comprises detecting means and a reference source, for spectroscopic analysis of a sample contained in a sample cell which is operatively associated with the integrating sphere; to the generation of digital control signals attendant the generation of the beams; and to the processing of the multiplexed, sample analysis results analog data signal, as provided by the detecting means, by aligning a digital control signal therewith in time and further operating upon the thusly aligned data signal to precisely calculate the sample analysis results.