Code Division Multiplexing of Fiber Optic and Microelectromechanical Systems (MEMS) Sensors

Multiplexing has evolved over the years from Emile Baudot's method of transmitting six simultaneous telegraph signals over one wire to the high-speed mixed-signal communications systems that are now commonplace. The evolution started with multiplexing identical information sources, such as plain old telephone service (POTS) devices. Recently, however, methods to combine signals from different information sources, such as telephone and video signals for example, have required new approaches to the development of software and hardware, and fundamental changes in the way we envision the basic block diagrams of communication systems. The importance of multiplexing cannot be overstated. To say that much of the current economic and technological progress worldwide is due in part to mixed-signal communications systems would not be incorrect. Along the vein of advancing the state-of-the-art, this dissertation research addresses a new area of multiplexing by taking a novel approach to network different-type sensors using software and signal processing. Two different sensor types were selected, fiber optics and MEMS, and were networked using code division multiplexing. The experimentation showed that the interconnection of these sensors using code division multiplexing was feasible and that the mixed signal demultiplexing software unique to this research allowed the disparate signals to be discerned. An analysis of an expanded system was performed with the results showing that the ultimate number of sensors that could be multiplexed with this technique ranges from the hundreds into the millions, depending on the specific design parameters used. Predictions about next-next generation systems using the techniques developed in the research are presented. iii Acknowledgments I ..