Development of an Optical Feedback Based High Accuracy Beam Transmissometer.

摘要

Work during this period has concentrated on the design and fabrication of the optical bridge microprocessor, specifically the implementation of the hardware. Significant progress has been made toward the development of a versatile data processor that can be used to acquire transmissometer data. A significant aspect of the design of the 'optical bridge' is the temperature compensation of the two light sensors. At the blue wavelength used in the bridge, sensors have a more significant temperature coefficient than at red wavelengths. In this design, the two sensors will be physically separated, producing undesirable effects in the presence of temperature gradients. One way of dealing with the temperature compensation problem is to do it numerically in a microprocessor-based system. The vehicle for doing this is a versatile data recorder. The data recorder is microprocessor-based and uses battery-backed memory for data storage. The real power for application to the optical bridge is the inclusion of a full-featured BASIC language interpreter. BASIC will allow functional approximations to temperature sensor responses and the use of data tables filled during calibration for highest precision. (aw)