ECE Faculty Candidate Colloquium
Friday **Special Time and Location** February 27 10:00 - 10:50 AM Kelley 1007 Jeffrey Walling Ph.D. from University of Washington Lecturer and Researcher University of Washington Efficient Transmitters for Wireless Communications Wireless devices have become nearly ubiquitous in everyday life, as sources of communications, knowledge and entertainment. With the increased presence of these devices, has come the desire for improved data rates and the desire to operate untethered from power sources for longer periods of time. Unfortunately these goals are not independent of one another, higher data rates comes at the expense of complex modulation. This modulation allows for spectrally efficient communication, but places a large burden on circuit design, perhaps the most on the power amplifier (PA). In a modern communication system, battery life is dictated by power consumption of the communication and control circuitry and one of the most dominant power consumers is the PA. PAs operate most efficiently when operating near their peak output power, howver with complex modulation schems such as QAM and OFDM, the signal statisticallly rarely operates near this peak. This talk will describe several methods which can be used to alleviate this problem by using external circuitry to modulate a more efficient non-linear PA. First a pulse-width and pulse-position modulation schem will be discussed for signals with moderate amplitude modulation, and second a system which uses a dual supply linear modulator for signals with significant amplitude modulation. Lastly, a description of ongoing and future research will be discussed. Biography: Jeffrey S. Walling received his Ph. D. from the University of Washington in 2008, where he is currently a lecturer and researcher. Prior to starting his graduate education he was employed at Motorola, Plantation, FL, working in cellular handset development. He interned for Intel, Hillsboro from 2006-2007, where he worked on highly digital transmitter architectures and CMOS PAs. His current research interests include low power wireless circuits, energy scavenging, high-efficiency transmitter architectures and CMOS PA design. Dr. Walling received the Analog Devices Outstanding Student Designer Award (2006), the Intel Foundation PhD Fellowship (2007-2008), and the Andrew Yang Award for outstanding graduate research from the University of Washington, Department of Electrical Engineering (2008).
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