CCD control and acquisition for a pulsed laser wavemeter

The hardware and software design and implementation of the data acquisition and processing systems of a laser wavemeter being built at NASA Langley Research Center are described. The wavemeter acquires sets of CCD/photodiode array-image data, produced by three Fabry-Periot interferometers for a pair of laser pulses every 200 milliseconds. Each image contains 1766 pixels digitized to 12-bit resolution. The acquisition system is composed of three discrete A/D channels running at a 1-MHz conversion rate, three diode-array sensors and two 4 K×9 FIFOs. By taking advantage of the analog shift-register storage, capability of the array, two sets of data can be read in rapid succession (less than 400 microseconds is required between laser firings, but data can be acquired faster) from each array. All six images are sent in interleaved fashion to the flight recorder for postprocessing on the ground, and one selected pair of these images is processed in semi-real-time by an 80286-based single-board computer to calculate the wavelength of a pulsed multimode Alexandrite laser