Increasing densities on magnetic data storage devices leads to problems of severe intersymbol interference (ISI), additive noise and non-linearities. Advanced detection strategies for magnetic recording channels fall into two categories: partial response equalization with maximum likelihood decoding and decision feedback equalization. This study focuses on doing an adaptive all-pass forward filter for the decision feedback channel. The decision feedback channel can be equalized by a low-order continuous-time filter, and does not require a transversal filter with high-precision multiplication. This results in considerable savings in both power consumption and chip die area. One problem that has yet to be addressed is how to adaptively set the coefficients of the all-pass filter. This thesis examines the design and performance of an adaptive all-pass filter. The performances in terms of the mean-squared error (MSE) of a first- and second-order all-pass are evaluated. They are compared to a conventional FIR filter design of various lengths. An adaptive algorithm based on the least mean-squared (LMS) error is developed and characterized over a range of storage densities. Since this does not require sampling of the filter input or any states of the forward filter, the system could be realized in continuous-time up to the decision device. Numerical simulations for various data densities and noise variances are done to verify the theoretically expected performance and the adaptation behavior of the all-pass. / Graduation date: 1997

The recent advances in VLSI technology have facilitated feature shrinking and hence a rapid increase in the levels of integration at the chip level. This increase in the level of integration has brought along with it a host of other constraints, the most crucial being timing management and increased power dissipation. Such constraints potentially prevent the full exploitation of the increased processing power made possible by technological advances. Timing in complex digital systems has traditionally been managed by using a global clock, controlled by which all the actions take place in lock-step. An alternative means of managing timing, called self-timing, simplifies the problems of timing management and results in a reduced power dissipation of complex digital systems. Systems designed using this self-timed or asynchronous protocol, work on a principle of handshaking, running at their own speed, governed by local timers and the availability of data on which to work. However, this hand-shaking introduces an overhead both in terms of hardware and computational speed. The work presented here examines the implementation of an adder, called a Parallel Half-Adder (PHA), which gains its speed by exploiting the power of asynchrony to calculate the sum. The adder has been implemented in the form of a tunable micropipeline and compared to traditional adders in terms of hardware complexity and speed. Comparable results have been obtained, implying that the overhead due to hand shaking is justified and the performance improvements due to self-timing can be fully exploited. The design of an array divider using the PHA has also been presented. / Graduation date: 1995

Thesis (M.S. in Telecommunications Systems Management)--Naval Postgraduate School, March 1990. / Thesis advisor(s): Boger, Dan C. Second Reader: Tulloch, A.W. "March 1990." Description based on signature page as viewed on August 25, 2009. Author(s) subject terms: Command, control, and communications systems. Includes bibliographical references (p. 49-52). Also available online.

This thesis presents the very practical and novel approach of using the Graphical User Interface (GUI) to compute the entire set of Proportional Integral Derivative (PID) controllers given the transfer function or the frequency response of the system under consideration. Though there is a wide spread usage of PID controllers in the industry, until recently no formal algorithm existed on determining a set of PID values that will stabilize the given system. The industry still relies on algorithms like the Ziegler- Nicholas or ad-hoc approaches in determining the value of PID controllers. Also when it comes to model free approaches, the use of Fuzzy logic and Neural network do not guarantee stability of the system. For a continuous Linear Time Invariant system Bhattacharyya and others have developed an algorithm that determines the entire set of PID controllers given the transfer function or just the frequency response of the system. The GUI has been developed based on this theory. The GUI also evaluates the user input performance specifications and generates a subset of stable controllers given the performance criteria for the system. This thesis presents an approach of automating the computation of entire set of stabilizing Proportional Integral Derivative (PID) controllers given the system transfer function or the frequency response data of the system. The Graphical User Interface (GUI) developed bridges the gap between the developed theory and the industry.

This thesis presents the very practical and novel approach of using the Graphical User Interface (GUI) to compute the entire set of Proportional Integral Derivative (PID) controllers given the transfer function or the frequency response of the system under consideration. Though there is a wide spread usage of PID controllers in the industry, until recently no formal algorithm existed on determining a set of PID values that will stabilize the given system. The industry still relies on algorithms like the Ziegler- Nicholas or ad-hoc approaches in determining the value of PID controllers. Also when it comes to model free approaches, the use of Fuzzy logic and Neural network do not guarantee stability of the system. For a continuous Linear Time Invariant system Bhattacharyya and others have developed an algorithm that determines the entire set of PID controllers given the transfer function or just the frequency response of the system. The GUI has been developed based on this theory. The GUI also evaluates the user input performance specifications and generates a subset of stable controllers given the performance criteria for the system. This thesis presents an approach of automating the computation of entire set of stabilizing Proportional Integral Derivative (PID) controllers given the system transfer function or the frequency response data of the system. The Graphical User Interface (GUI) developed bridges the gap between the developed theory and the industry.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 174-179). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (p. 127-133).

Thesis (Ph.D.)--University of Texas at Arlington, 2009.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (p. 253-265).

Thesis (Ph. D.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Herschel H. Loomis, Jr., Alan A. Ross. Includes bibliographical references (p. 157-161). Also available online.