News

December 10, 2007

Contributing to the Digital Age

David Young ’08 discusses his honors thesis under the guidance of Todd Wey, assistant professor of electrical and computer engineering

David Young ’08 (Bensalem, Pa.) is a Marquis Scholar who is pursuing a B.S. in electrical and computer engineering and an A.B. in computer science. He is working on an honors thesis involving crystal oscillator circuits with Todd Wey, assistant professor of electrical and computer engineering. The following is a firsthand account of Young’s experiences with his thesis.

I have had the goal of writing a thesis almost since my arrival at Lafayette College. With adequate credits, I was able to take junior-level courses during my sophomore year. It was from these classes that I had the fortune of interacting on a personal level with several of the graduating seniors of that year (2006). Almost half of those seniors were writing theses of their own. Talking to them inspired me to pursue the same path when my time came. They were at the top of their class and that’s where I wanted to be.

It wasn’t until junior year that a thesis topic sort of fell into my lap. Although I understand many aspects of the electrical and computer engineering field, there are a few disciplines that I am deeply interested in. I have a strong inclination for analog electronics.

I approached the department’s electronics professor, Todd Wey, about the possibility of doing summer EXCEL research with him. We discussed his ideas for summer research. I indicated to him my desire to complete a large project as my senior thesis. Through our talks, I decided to explore the area of crystal oscillator circuits. More specifically, my thesis deals with the control and stabilization of such circuits and our attempt at a new digital method of control.

Crystal oscillators are very important in this digital age; they form the basis for accurate timing in watches and the clock for computers. Stability affects accuracy, and no one wants to have to reset their watch every few days because it’s too fast or too slow. My thesis work is based upon simulation of the control algorithm with the crystal. These simulations will show the transient effects of switching control parameters on the crystal circuit. These problems will have to be minimized or controlled in order for the system to remain stable.

The main goal of the research is to design a simulation of a crystal oscillator that can also include the digital control. The problem is that a conventional circuit simulator will not work because the digital control seriously degrades the speed of the simulation.

Therefore, it is necessary to characterize the oscillator in a fixed time step. This step was accomplished over the summer through an energy analysis and verified through SPICE (a circuit simulator) simulations. With this in place, the circuit can be characterized in behavioral modeling in a design language called Verilog. Verilog also is the perfect environment to implement and test the digital control system.

When complete, this new method of circuit simulation would be very important to crystal oscillator design. Before any new design can be put into production, it must be simulated and tested to ensure that it is stable and performs expectedly. For some designs, this can require as many as 10-100 million clock cycles. This involves a lot of time, and applies solely to designs containing only analog components. Several outside researchers have designed computer programs to predict the steady state response of a crystal circuit for those types of circuits. With this new system, a derivative thereof, designers could design and test digital control for crystal oscillators.

I feel very fortunate to be doing this research. I am excited to be expanding the research in the field of crystal oscillators. This method of control is new and in the future, I could be helping to design a controller that I laid the foundations for here at Lafayette.

Already, this research is helping me in my job search. Many employers are interested in various aspects of my research. It gives me experience working toward a solution on my own. The answer to the problem is not known yet and I am excited to continue this research this year and make it into a thesis.

Young is a member of the Phi Kappa Psi fraternity and serves as its intramural chairman. He is a member of the Ultimate Frisbee team and general manager of the College radio station WJRH 104.9 FM. He spent January 2007 in Austria and Germany taking a three-week interim-session course.

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