Research Projects

Broadband Digitally Controlled Oscillator in 90nm CMOS (2.8GHz to 10.3GHz) ~ summer 2007

• Supervisor: Professor A. Chan Carusone

• Abstract: Voltage controlled oscillators (VCO's) are the cores of phase-locked loops (PLL's) that synthesize clock/signal frequencies for all wireless communication devices. As device size decreases, it becomes desirable to implement the PLL digitally in order to take advantage of successively smaller feature sizes. However, the analog VCO is a crucial piece of circuitry that is incompatible with a digital PLL architecture. Therefore there is great need for a digitally controlled oscillator (DCO) to replace the VCO and make the PLL a digital, integrable unit. Furthermore, a very wide tuning range is desired in the DCO to accommodate a variety of wireless applications operating from 2.4 GHz to 10.6 GHz. The work presented here is a DCO that employs a novel topology comprising two coupled two-stage ring oscillators that can be programmably reconfigured to achieve a maximum tuning range of 2.8GHz to 10.3GHz. The DCO achieves a phase noise of -108dBc/Hz at 6.5GHz center frequency 10MHz offset and a power dissipation of 3.6mW at the same frequency. These numbers are comparable to the best prior art, but the tuning range of the proposed DCO is much wider.

• PowerPoint presentation [download: 463KB]

• Supervisor: Professor A. Steinberg

• Abstract: Lithography technology employing classical light is reaching its limit in resolution due to the effects of diffraction. When light travels through a mask of slits used to manufacture microchips, the minimum of the resulting feature size is determined by the width of the interference pattern from the diffracted wavelets. This experiment proposes to show that this classical limit (also called the diffraction limit) can be bettered by utilizing the quantum mechanical properties of entangled multi-photon states. Under idealized conditions, the diffraction limit of an N-photon state can be N times narrower than the smallest resolvable distance for classical light. Here, a 3-photon NOON state generated via spontaneous parametric down conversion (SPDC) will be used as a quantum light source. The interference of this polarization-entangled state will be imaged through a Ronchi ruling. Three-photon coincidence counts will then reveal a pattern with a periodicity that is one third of that of classical light, thus demonstrating super-resolution and quantum lithography.

• PowerPoint presentation [download: 1.98MB]

• pictures of the set-up

top view

side view

Universal Multimedia Access with ePresence ~ summer 2005

• Supervisor: Professor K. Plataniotis

• Description: This project aims to satisfy the ever-growing demand for easy access to multimedia anytime and anywhere on a network, using any terminal device. To demonstrate the feasibility of meeting such a demand, we focused on developing a virtual classroom where registered users can view archived and live lecture videos synchronized with PowerPoint slides. I was responsible for implementing a web-based interface for this virtual classroom that adapted itself to the client's device (eg. PC, PDA or Smartphone) and correctly reproduced the relative timing of all the multimedia content, while allowing for maximum browsing flexibility for the user.

• Documentations and software developed for this project can be found here.

Course Projects

• the telephone consists of: a microphone, a pre-amp, an A/D converter, an optical link, a D/A converter, a class AB power amp, and an 8ohm speaker

• the breadboard

• The project was a one-year design experience in groups of three students. My group built a machine that takes up to four different kinds of soup ingredients and packages them into canisters according to user-specified weights and combinations. I worked on the electrical subsystem, which was the critical link between the software and the mechanical components of the machine.

• Below is a picture of the circuit board I made. It takes readings from 4 force sensors used for weighing the ingredients and relays that information to the PIC Microcontroller. Then, it takes digital instructions from the microcontroller and converts them into analog signals in order to drive the mechanical parts (3 stepper motors and 6 solenoids). Decoders were used to reduce the number of pins required on the microcontroller.

• pictures of the machine

• Well, these aren't engineering projects, but I place them here because they were quite nicely written - at least, the grader thought so. The first review garnered me an A; as for the second, she commented: "This is easily comparable to reviews found in academic journals done by professors with specialties in these fields." and gave me an A+. Take a respite from the humdrum of technical writing and tune in to the mellifluous voice of a literary composition.

• Forced Founders: Indians, Debtors and Slaves and the Making of the American Revolution in Virginia by Woody Holton

• Ladies of Labor, Girls of Adventure: Working Women, Popular Culture, and Labor Politics at the Turn of the Twentieth Century by Nan Enstad

• materials: 1mm*1m*1m Bristol board and 1 bottle of glue

• bridge type: beam, supported only at the two ends

• detailed calculations were done on the bridge and the predictions were: 1). 40kg metal train will be able to traverse the bridge 2). a maximum of 700N of weights can be hung at a single point 2/3 of the way across the bridge

• results: 1). passed the train test 2). bridge collapsed with 800N of weights were placed at a single point (shows that the calculations were very accurate and construction was very precise)

finished bridge (the hole is for hanging the weights)

bridge under test

glue failed under shear stress after 800N of weights were hung at that point