Signal acquisition and processing system for reduced output signal drift in a spectrophotometric instrument

摘要

A spectrophotometric instrument including a source of measurement light wavelengths, a probe, a plurality of send fibers coupled to the measurement light signal source and a plurality of receive fibers for receiving light including the measurement light signals. The instrument also has reference signal optics coupled to the measurement light signal, a detector for generating electrical signals representative of the measurement signals and the reference signals optical paths for coupling the measurement signal from the receive fibers and the reference signal portion from the reference signal optics to the detector, and an optical path control for selectively allowing either the measurement signal portion or the reference signal portion to the detector. This enables the detector to output a reference value when the reference signal is coupled to the detector and a measurement value when the measurement signal is coupled to the detector.