Mixed-Signal Processor for a Fabry-Perot Interferometric Fiber Optic Pressure Sensor.

This dissertation presents the design and implementation of a novel mixed-signal processing method for recovering the pressure information obtained from a fiber optic Fabry -Perot interferometric sensor. The sensor is employed for measuring in-cylindel-pressure in internal combustion engines. The unprocessed sensor signal contains both temperature and pressure perturbations. These are separated using digital techniques and the resultant pressure information is provided as an analog output voltage for proper connectivity to a feedback control unit used to improve the fuel efficiency of the engine and lower the emissions of harmful gases. A prototype has implemented and tested in two different engines, one powered by gasoline and the other by natural gas. The results of several tests, including a comparison with the output of a commercial piezoelectric pressure sensor, are presented to prove the efficiency of the algorithm. Finally, a monolithic silicon implementation of the mixed-signal processing circuitry using a CMOS 2mum Pwell double poly, double metal technology is presented.