Thesis (M.S.)--University of Wisconsin--Madison, 1980. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 65-68).

Thesis (M.S.)--University of Wisconsin--Madison, 1964. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 41.

Zugl.: Erlangen, Nürnberg, University, Diss., 2005.

This thesis is concerned with the development of a slope-feedback coder, the purpose of which is to reduce the bandwidth required for the transmission of telephone-quality speech. Three similar coders, which operate separately on each of the three principal formants in speech, are required. The coding results in a reduction in the speech bandwidth from 3200 cps to 500 cps; the corresponding channel-capacity required is reduced from 32,000 bits per second to 6,200 bits per second. Theoretical statements of the performance of the coder are given showing how it transforms some stylised input signals (e.g. ramp and sinewave). From these statements, it is shown that: a) a single channel for each coder leads to very inferior performance - it is shown that two channels are required, and this gives good performance using much the same bandwidth; b) the signal-to-noise ratio required is moderate. A slope-feedback coder has been constructed, and a technical description of this apparatus is given. Experimental tests of the coder operating on simulated formants justify the theoretical predictions to within a root-mean-square error of twelve percent. This error decreases to six percent if those errors which are most subject to apparatus error are not considered. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

This thesis describes the simulation of a digital communication system on a digital computer. Delta modulation was chosen as the system, and its mode of action is first described. Several variations of the basic system are possible. In order to get the best transmission quality, a careful choice must be made of the system and of its design parameters. Conventional methods of finding these optimum parameters have difficulties which digital simulation can circumvent. The programming of the ALWAC III-E computer for this task is described. Difficulties were encountered due to the modest speed of the computer. The simulation experiments yielded many results of interest concerning the operation of both simple and complex delta modulation systems with different design parameters, and allowed an optimum system to be designed. Where it is possible to compare results with previous experimental work, the agreement is good. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

No description available.

Thesis (Ph. D.)--Brigham Young University. Dept. of Electrical and Computer Engineering, 2005. / Includes bibliographical references (p. 137-141).

A project report sUbmitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering. Sandtoh, 1995. / Amplitude modulation, is the oldest modulation technique used for voice communication.It is the simplest and cheapest way to modulate and demodulate voice, and as a result, it did not lose much popularity in spits of the development of other, more efficient modulation technique. This project offers a new approach for AM demodulation. The two sidebands are separated and divided into many su-bands. The signals with the lowest noise level are solected and thier levels are individually adjusted according to signal conditions. The result is reduction of over 35 dB in continuous interference and about 15 dB in whit noise level. The new detector and about out-performs the conventional detectors in all aspects and can be used in applications where top performance is required and where mone is no object.

by Kingsley, King-chi, Kwan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 85-88). / Tables of Contents / Lists of Figures & Tables / Acknowledgments / Abstract / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Digital Communication System --- p.P. 1 / Chapter 1.2 --- Channel Coding --- p.P. 1 / Chapter 1.3 --- Convolution Encoder --- p.P. 4 / Chapter 1.4 --- Additive White Gaussian Noise (AWGN) Channel --- p.P. 7 / Chapter 1.5 --- Trellis Diagram --- p.P. 8 / Chapter 1.6 --- Error Event and Free Distance --- p.P. 8 / Chapter 1.7 --- Euclidean Distance --- p.P. 10 / Chapter 1.8 --- Organization of the Thesis --- p.P. 11 / Chapter Chapter 2 --- QAM and MTCM / Chapter 2.1 --- Introduction --- p.P. 13 / Chapter 2.2 --- M-ary Quadrature Amplitude Modulation (QAM) / Chapter 2.2.1 --- M-ary Digital Modulation --- p.P. 13 / Chapter 2.2.2 --- Quadrature Amplitude Modulation (QAM) --- p.P. 14 / Chapter 2.2.3 --- Probability of Bit Error of M-ary QAM --- p.P. 16 / Chapter 2.3 --- Trellis Coded Modulation (TCM) --- p.P. 17 / Chapter 2.4 --- Multiple Trellis Coded Modulation (MTCM) --- p.P. 19 / Chapter Chapter 3 --- Set Partitioning of Signal Sets / Chapter 3.1 --- Introduction --- p.P. 21 / Chapter 3.2 --- Traditional Set Partitioning Methods / Chapter 3.2.1 --- Ungerboeck's Set Partitioning Method --- p.P. 21 / Chapter 3.22 --- Set Partitioning by M.K. Simon and D. Divsalvar --- p.P. 23 / Chapter 3.3 --- The new Set Partitioning Method / Chapter 3.3.1 --- Nomenclature of the Signal Points in the Signal Constellations --- p.P. 24 / Chapter 3.3.2 --- Generation of the Signal Sets --- p.P. 26 / Chapter 3.3.3 --- Partitioning of the Signal Sets / Chapter 3.3.3.1 --- Input Constraints of the Partitioning Method --- p.P. 30 / Chapter 3.3.3.2 --- The Set Partitioning Method --- p.P. 30 / Chapter 3.3.4 --- Distance Properties of the Partitioned Signal Sets --- p.P. 36 / Chapter 3.3.5 --- The Selection Scheme --- p.P. 39 / Chapter 3.3.6 --- Assignment of Signal Subsets into Trellis --- p.P. 42 / Chapter Chapter 4 --- Performance Evaluation / Chapter 4.1 --- Introduction --- p.P. 46 / Chapter 4.2 --- Upper Bound of Error Probability / Chapter 4.2.1 --- Probability of Symbol Error --- p.P. 46 / Chapter 4.2.1.1 --- Upper Bound on Probability of Symbol Error --- p.P. 48 / Chapter 4.2.1.2 --- Computation of the Transfer Function --- p.P. 49 / Chapter 4.2.2 --- Probability of Bit Error --- p.P. 51 / Chapter 4.3 --- Computation of the Free Distance --- p.P. 53 / Chapter Chapter 5 --- Results Presentation and Discussions / Chapter 5.1 --- Introduction --- p.P. 58 / Chapter 5.2 --- Results Presentations / Chapter 5.2.1 --- Normalized Square Free Euclidean Distance --- p.P. 58 / Chapter 5.2.2 --- Error Probability --- p.P. 71 / Chapter 5.3 --- Discussions --- p.P. 77 / Chapter Chapter 6 --- Conclusions --- p.P. 83 / Bibliography --- p.P. 85 / Chapter Appendix A - --- Flowchart of the Program --- p.P. 89 / Chapter Appendix B - --- Tabulated Results of d2free --- p.P. 104

Combined coding with modulation is an important topic. It is verified in this thesis that a combined decoder and demodulation Viterbi receiver has a better error probability than a cascade of two separate Viterbi decoder and demodulator. Conventionally, the free distance is taken as the principle criterion for computing the error probability for coding or modulation. In many cases, distance spectrum needs to be provided for analyze the Maximum likelihood decoding. However, it is difficult for computing the distance spectrum for a combined coding with modulation because of a nonlinear structure inside. In this thesis, we first build an augmented trellis for the combined coding with modulation. Applying the concept of difference by exclusive OR and regular subtraction to the augmented trellis, we build an improved virtual trellis. As a consequence the distance spectrum for our problem can be computed because of the linear structure of the virtual trellis. The distance spectrum for different convolutional codes and CPM systems are investigated by us. Experiments results have demonstrate that a better distance spectrum implies a better error ability.