No description available.

No description available.

Thesis (PhD)--University of South Australia, 2000

Thesis (PhD)--University of South Australia, 2000

Thesis (M.S.)--Rochester Institute of Technology, 1994. / Typescript. Includes bibliographical references (leaves 89-91).

Thesis (Ph. D.)--University of Missouri-Columbia, 2005. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (May 25, 2006) Vita. Includes bibliographical references.

The purpose of this dissertation is to investigate the effects of non-linear propagation on a proposed digital microwave radio link which employs MSK modulation, in order to specify a suitable form of adaptive equalization. MSK is a coherent modulation technique, having improved spectral roll-off over FSK because it avoids the abrupt phase changes at the bit transitions. However computer simulations and field results indicate that MSK digital radio links do suffer from intersymbol interference and crosstalk. Software and hardware simulations of multipath propagation are based on Rummlers simplified three path model and statistics. The results obtained from the computer simulations of the MSK link and multipath propagation confirm that there is no simple relationship between the multipath parameters and the BER degradation which could be used in the design of an equalizer. The choice of adaptive equalizer is made based on criteria such as construction cost, circuit complexity, and performance improvement. It is known from ray model analysis that at a transmitting frequency of 23 GHz deep fading will only occur on links longer than 5.24 kms. However even on hops of length 5 km' s the fade time is-in the order of 1612 seconds/month (calculated using Rummlers model). A ldB increase in theoretical Eb/No will also be required to overcome potential modem imperfections. It is necessary to have a time domain equalizer which can compensate for both amplitude and phase distortions simultaneously by acting directly on the ISI. The equalizer structure chosen is a 2-by-2, fractionally spaced, decision feedback, complex adaptive equalizer with zero forcing control algorithm.

No description available.

Adaptive filtering may be applied in areas where an optimal filtering algorithm may not be known a-priori and where the filtering operation may be non-stationary. This field, or more generally, the field of adaptive systems, is one which may be regarded as mature, having been the subject of considerable research effort in the areas of control and signal processing for almost four decades. DFE (decision feedback equalization) in various forms has been proposed for detection on magnetic recording channel. An allpass filter is an alternative to the FIR (finite impulse response) forward equalizer which is normally implemented with DFE. This is because the allpass filter is a lower power and complexity alternative, though its behavior and performance are not very well understood yet. Here, an allpass structure implemented as first and second order IIR (infinite impulse response) filters is examined. Convergence for the LMS (least mean square) adaptation algorithm is studied and, moreover, some convergence conditions and bounds are developed, similarly to the well known FIR case. This thesis provides an useful analytical study of convergence of IIR adaptive filtering. This is accomplished by a systematic approximation of the covariance terms of the adaptive coefficients. The range of the step-size parameter of the LMS algorithm is developed under some simplifying assumptions. All the results obtained are verified by simulation (Matlab and C routines are used). / Graduation date: 1998

Thesis (M.E.)--University of Canterbury, 2007. / Typescript (photocopy). "14 February 2007." Includes bibliographical references (leaves [97]-100). Also available via the World Wide Web.