Thesis (M.S.)--University of Florida, 2004. / Title from title page of source document. Document formatted into pages; contains 137 pages. Includes vita. Includes bibliographical references.

Thesis (M. Sc.)--University of Alberta, 2009. / Title from PDF file main screen (viewed on Sept. 4, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Communications, Department of Electrical and Computer Engineering, University of Alberta." Includes bibliographical references.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 91-100). Also available in electronic version.

This research concerns the continuing development of Seaweb underwater networking. In this type of wireless network the radio channel is replaced by an underwater acoustic channel which is strongly dependent on the physical properties of the ocean medium and its boundaries, the link geometry and the ambient noise. Traditional acoustic communications have involved a priori matching of the signaling parameters (e.g., frequency band, source level, modulation type, coding pulse length) to the expected characteristics of the channel. To achieve more robust communications among the nodes of the acoustic network, as well as high quality of service, it is necessary to develop a type of adaptive modulation in the acoustic network. Part of this process involves estimating the channel scattering function in terms of impulse response, the Doppler effects, and the link margin. That is possible with the use of a known probe signal for analyzing the response of the channel. The estimated channel scattering function can indicate the optimum signaling parameters for the link (adaptive modulation). This approach is also effective for time varying channels, including links between mobile nodes, since the channel characteristics can be updated each time we send a probe signal.

Thesis (Ph.D.)--University of Florida, 2005. / Title from title page of source document. Document formatted into pages; contains 101 pages. Includes vita. Includes bibliographical references.

published_or_final_version / Computer Science and Information Systems / Master / Master of Philosophy

Oversampling analog-to-digital and digital-to-analog converters are gaining more popularity in many signal processing applications. Delta-sigma modulators are used in practical applications of oversampling systems because of their apparent practical advantage over other oversampling converters in terms of insensitivity to the inevitable imperfection of the analog circuitry. In Δ∑ modulators, analog integrators are always very important components and are usually modeled as ideal in real applications. However, theoretical analysis shows that the integrator nonideality due to capacitor mismatching and finite op-amp gain cause large signal-to-noise ratio degradation. The primary disadvantages of the dual-quantization and cascade modulators are that they rely on the precise cancellation of terms derived from two separate circuits, one analog and one digital, and that there are added complexities on the digital sides. This thesis describes digital adaptive correction of nonidealities in dual-quantization and cascade modulators. The sources and effects of nonidealities in a first-order delta-sigma loop are analyzed. Simple correction schemes are presented, and theoretical SNR improvements are calculated and compared with simulation results. / Graduation date: 1993

Thesis (PhD)--University of South Australia, 2001

Thesis (Ph. D.)--Ohio University, June, 1990. / Title from PDF t.p.

Thesis (Ph. D.)--University of Canterbury, 2008. / Typescript (photocopy). "December 2008." Includes bibliographical references (p. 165-174). Also available via the World Wide Web.