Real-time digital signal processor for a fiberoptic interferometric sensor

A new digital signal processing system based on parallel operation of a 32-bit microcontroller MC68332 (Motorola) and a 24-bit digital signal processor DSP56002 (Motorola) has been designed to monitor a fiberoptic sensor which operates on the principle of white light interferometry. The system is capable of accommodating the high throughput of the sensor signal from two fiber Fabry-Perot interferometers (FFPIs).; The primary goal of this system is a low-cost prototype signal processor as a stand-alone module operating at a reasonable speed. The secondary goal is to make the processing period (reading time) as short as possible because the signal processing algorithm includes a crosscorrelation between raw signals requiring several million CPU instruction cycles. The use of DSP shifts much of the functionality and development work from hardware to software and allows the microcontroller to have enough time to control the fiber sensor system. The monitor software consists of two independent modules for each processor and takes advantage of assembly language to enhance its performance.; The system has been designed, assembled, and tested with simulated fringe patterns generated by a personal computer and real fringe patterns from a fiberoptic sensor captured by LabView data acquisition system. The system shows good stability with resolution of 0.0015 fringes without any fringe misidentification.