Digital Signal Processing Seminar

Advanced Filter Design for Signal Processing and Communications Systems

Prof. Brian L. Evans
Department of Electrical and Computer Engineering
The University of Texas at Austin
Austin, TX 78712-1084

Friday, November 21st, 2:00 PM, ENS 302

Research in collaboration with Mr. Niranjan Damera-Venkata (UT Austin), Mr. Douglas Firth (Precision Filters), Prof. Edward Lee (UC Berkeley), Prof. Miroslav Lutovac (Univ. of Belgrade), Prof. Dejan Tosic (Univ. of Belgrade), Mr. Kenneth White (Diva Communications).

The primary drawback to classical filter design techniques is that they return only one design from an infinite collection of alternative designs, or fail to design filters when solutions exist. These classical techniques hide a wealth of alternative filter designs that are more robust when implemented in analog circuits, digital hardware, and embedded software. This talk presents two complementary approaches for infinite impulse response filter design that consider the bounded infinite solution space when finding designs that exhibit the desired behavior when implemented using a particular technology. Behavioral characteristics include magnitude response, phase response, and step response.

The first approach is an algebraic approach that returns closed-form solutions to the filters that lie at the boundaries of the infinite design space. Based on this approach, we present case studies of optimal analog and digital IIR filters that cannot be designed with classical techniques. We describe the formal, mathematical framework that underlies their solutions. The second approach is a robust, extensible numerical optimization technique that optimizes existing filter designs for multiple behavioral and implementation characteristics. We have automated both approaches in Mathematica and Matlab.

Brian L. Evans is an Assistant Professor in the Department of Electrical and Computer Engineering at The University of Texas at Austin, and the Director of the Embedded Signal Processing Laboratory within the Center for Vision and Image Sciences. His research interests include real-time embedded systems; signal, image and video processing systems; system-level design; symbolic computation; and filter design. Dr. Evans has published over 45 conference and journal papers in these fields. He developed and currently teaches Multidimensional Digital Signal Processing, Embedded Software Systems, and Real-Time Digital Signal Processing Laboratory. His B.S.E.E.C.S. (1987) degree is from the Rose-Hulman Institute of Technology, and his M.S.E.E. (1988) and Ph.D.E.E. (1993) degrees are from the Georgia Institute of Technology. From 1993 to 1996, he was a post-doctoral researcher at the University of California at Berkeley with the Ptolemy Project. Ptolemy is a research project and software environment focused on design methodology for signal processing, communications, and controls systems. In addition to Ptolemy, he has played a key role in the development and release of six other computer-aided design frameworks, including the Signals and Systems Pack for Mathematica, which has been on the market since the Fall of 1995. He is a Senior Member of the IEEE, and the recipient of a 1997 National Science Foundation CAREER Award.

A list of digital signal processing seminars is available at from the ECE department Web pages under "Seminars". The Web address for the digital signal processing seminars is