Showing papers by "Kenneth Steiglitz published in 1989"

Optimization of pre- and post-filters in the presence of near and far-end crosstalk

Abstract: Full-duplex data communications are considered over a linear, time-invariant, multi-input/multi-output channel. For both the continuous- and discrete-time cases, optimal multi-input/multi-output transmitter and receiver filters are derived using the minimum mean-square error (MSE) criterion, with a power constraint on the transmitted signal, in the presence of both near- and far-end crosstalk. The discrete-time problem is solved for two different filter models: arbitrary linear (IIR) (infinite-complexity) and fixed-order (FIR) filters. In addition, the optimal transmitter and receiver filters are derived for the case in which the transmitted signal is a pulse-amplitude-modulated data signal. For a particular two-input/two output channel model in the FIR case, the behavior of the MSE as a function of the allocation of matrix taps between transmitter and receiver filters and of timing phase is studied. In this case, the jointly optimal transmitter and receiver filters are obtained numerically using an iterative technique. For the channel model considered, the MSE is a very sensitive function of timing phase but is nearly independent of how taps are allocated between the transmitter and receiver filters. >

System Theoretic Models for High Density VLSI Structures

Abstract: : This research project involved the development of mathematical models for analysis, synthesis, and simulation of large systems of interacting devices. The work was motivated by problems that may become important in high density VLSI chips with characteristic feature sizes less than 1 micron: it is anticipated that interactions of neighboring devices will play an important role in the determination of circuit properties. It is hoped that the combination of high device densities and such local interactions can somehow be exploited to increase circuit speed and to reduce power consumption. To address these issues from the point of view of system theory, research was pursued in the areas of nonlinear and stochastic systems and into neural network models. Statistical models were developed to characterize various features of the dynamic behavior of interacting systems. Random process models for studying the resulting asynchronous modes of operation were investigated. The local interactions themselves may be modeled as stochastic effects. The resulting behavior has been investigated through the use of various scaling limits, and by a combination of other analytical and simulation techniques. Techniques arising in a variety of disciplines where models of interaction have been formulated and explored were considered and adapted for use.