Francis P. Dawson

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–A 4-bit fourth-order delta-sigma modulator with a widely programmable center frequency is presented. Novel methods for quantizing and implementing the digitally programmable modulator coefficients enable performance comparable to state-of-the-art discrete-time fixed-frequency modulators at any center frequency from dc to 0.31f s in steps of 0.0052f s. The(More)
Piezoelectric devices, such as piezoelectric traveling- wave rotary ultrasonic motors, have composite piezoelectric structures. A composite piezoelectric structure consists of a combination of two or more bonded materials, at least one of which is a piezoelectric transducer. Piezoelectric structures have mainly been numerically modeled using the finite(More)
Piezoelectric devices, such as piezoelectric traveling wave rotary ultrasonic motors, have composite piezoelectric structures. A composite piezoelectric structure consists of a combination of two or more bonded materials, where at least one of them is a piezoelectric transducer. Numerical modeling of piezoelectric structures has been done in the past mainly(More)
—High-temperature high-pressure arc lamps are used to thermally process semiconductor wafers. An accurate dynamic model that links the radiation output to the current input would facilitate the design of a power circuit that optimizes energy transfer to the arc. In this paper, a dynamic arc model is derived using averaging of the energy balance equation(More)
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