The first part of this thesis describes the design and construction of a pulse communications system called delta modulation. A simple transistorized coder and decoder was built to convert speech signals into binary pulses, and back again. This system was tested in several ways: the circuit performance was checked electronically, and the quality of transmission through the system was judged by listening tests and by comparison with special tapes containing controlled amounts of signal and thermal noise. The second part concerns the design and construction of a compressor and expandor that can be used with a delta system in order to improve its transmission quality. A fast-acting compressor and expander was constructed using diode-bridges as non-linear elements. Tests of the two components used "back-to-back" showed a satisfactory matching of their characteristics. If these components were used with the delta modulation system, there would be a considerable increase in the range of signal levels that could be transmitted with reasonable quality. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

The signal model in Kalman filtering is usually described by a linear dynamical equation driven by generating noise. In this thesis, we set the generating noise to be a white binary sequence and feed to a dynamic system and then forward to a phase modulation system. This discrete generating noise makes the generating signal to be discrete. However, there still are too many states for this discrete signal. In this thesis, we apply the tree structure to define the states. The number of states is reduced by focusing on the most probable working states. To save the bandwidth, we interpolate the generating signal in two methods. One is before the phase modulation, the other is after phase modulation. The former one has a better error rate than GMSK for SNR between- 2dB~5dB and if given the bandwidth around 500k(Hz). The former one has a better error rate than GNSK for SNR between - 3dB~5dB and if given the bandwidth around 500k(Hz). Our error performance is studied by computer simulation. This error performance is also successfully analyzed by computing the distance spectrums

Researchers previously have found a correlation between the strength of the auditory steady-state response (ASSR) and corresponding auditory behavioral measurements such as speech recognition scores, thus concluding that the ASSR can be used as an objective measurement of auditory supra-threshold properties. In the present study, it was hypothesized that the increase in the strength of the ASSR at different modulation depths would be reflected in corresponding psychophysical measures, specifically, auditory modulation discrimination. These relationships were investigated in normally-hearing listeners at modulation rates of 40 and 80 Hz for both amplitude (AM) and mixed modulation (MM), at several modulation depths. Analyses were completed for two sets of measurements derived from the physiological and behavioral responses. For the first analysis, derived measures of iso-neurometric thresholds were compared to isometric modulation discrimination thresholds. For the second analysis, derived estimates of physiological neurometric slope were compared to estimated psychometric function slopes. Mixed-model analyses for both of these measures revealed significant or near-significant relationships between physiological and psychophysical measures at 40 Hz for AM and at 80 Hz for MM. Bootstrap resampling analyses were completed to estimate the distribution of the resultant statistics. Implications regarding the location of neural encoding for amplitude and frequency modulation were discussed. / text

No description available.

Thesis (PhD)--University of South Australia, 1994.

Thesis (PhD)--University of South Australia, 1994.

xii, 77 leaves : ill., appendices / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Electrical Engineering, 1973

Thesis (Ph.D.) -- University of Adelaide, Dept. of Electrical Engineering, 1973.

Ulm, Univ. Diss., 2006.

Th. doct.--Signal et images--Paris--ENST, 1995. / En appendice, un choix de textes en français. Bibliogr. p. 250-259. Résumé en anglais et en français.