Gordon W. Roberts
McGill University
Title:
Time-Domain Analog Signal Processing
Abstract:
CMOS technologies continue to be the choice for the integration of electronic computing, memory and signal processing applications. This is driven largely by the fact that CMOS technologies offer the cheapest integrated solution, combined with an aggressive roadmap that has been accurate for over 3 decades; the ideal business solution. For the most part, transistor densities have increased exponentially allowing for a multitude of functionality to be integrated into a very small silicon area. Subsequently, the industry is seeing two drawbacks to this approach. The first is an exponentially increasing power problem and the second is the variability problem a single transistor experiences during manufacture, either between die-to-die or from a current technology to a newer one. The latter issue has a direct impact on those circuits that derive their functionality from the analog behavior of a single transistor. While the power density issues remains, industry is introducing more parallelism into their system architectures thereby reducing some of the power concerns, at least for now. Looking ahead, IBM has recently announced a water-cooled IC technology that has the potential to improve the heat sink capability by orders of magnitude.
The goal of this presentation is not to talk about the power problem associated with advanced ICs, but rather to talk about a new method of performing analog signal processing that is amenable to advanced CMOS processes and one that can be easily calibrated at manufacture for process variations. Time-mode signal processing (or TMSP for short) is a promising candidate to replace conventional voltage-mode methods. TMSP may be defined as the detection, storage, and manipulation of sampled analog information using time-difference variables. Moving to the time domain, the designer will be able to implement analog functional blocks using digital cells whose time delay between two rising edges is the variable of interest rather than the magnitude of a voltage or current signal.
We will begin our presentation with an introduction into time-difference signals and how to convert voltage mode signals into time mode signals and vice versa. This will be then followed by a description of some basic analog signal processing elements that perform addition, subtraction, multiplication and integration, etc.. Also, we will introduce the concept of time amplification. Subsequently, we'll use these building blocks to construct various data converter circuits and simple filter circuits using PLLs.
Biography:
Gordon W. Roberts received the B.A.Sc. degree from the University of Waterloo, Canada, in 1983 and
the M.A.Sc. and PhD degrees from the University of Toronto, Canada, in 1986 and 1989, respectively,
all in electrical engineering. Dr. Roberts is currently a full professor at McGill University where
he holds the James McGill Chair in Electrical and Computer Engineering. Over the years, he has conducted
extensive research on analog integrated circuit design and mixed-signal test issues. He has co-written
two undergraduate textbooks, entitled: SPICE For Microelectronic Circuits with Prof. Adel Sedra and An
Introduction to Mixed-Signal IC Test Measurement with Mark Burns. He also co-written three research
monographs, Analog Test Signal Generation Using Periodic SD-Encoded Data Streams (with Benoit Dufort),
Analog Signal Generation For Built-In Self-Test Of Mixed-Signal Integrated Circuits (with Albert Lu),
and Design and Analysis of Log-Domain Filter Circuits (with Vincent Leung). He has published over 110 papers
in scientific journals and conferences, and he has contributed 11 chapters to other books. He is past associate
editor of the IEEE Transaction on Circuits and Systems, Part II, and past associate editor for the IEEE Design
& Test of Computers Magazine. Prof. Roberts was also a past Distinguished Lecturer for the IEEE Computer
Society and the Circuits and Systems Society.. Prof. Roberts has received numerous department, faculty and
university awards for teaching test and electronics to undergraduates, and received several IEEE awards for
his work on mixed-signal testing. Prof. Roberts is presently the program chair of the IEEE International
Test Conference. Dr. Roberts is a Fellow of the IEEE. In 2003 he took leave from McGill to help start DFT
Microsystems, Inc, a company specializing in high-speed timing measurement. His current research includes
analog IC design methods and various issues related to mixed-signal test.
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