EFFECTS OF QUANTIZATION ON THE UTILITY OF VOICE FUNDAMENTAL FREQUENCY AS AN ACOUSTIC SUPPLEMENT TO SPEECHREADING.
Item
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Title
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EFFECTS OF QUANTIZATION ON THE UTILITY OF VOICE FUNDAMENTAL FREQUENCY AS AN ACOUSTIC SUPPLEMENT TO SPEECHREADING.
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Identifier
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AAI8713765
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identifier
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8713765
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Creator
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HNATH-CHISOLM, THERESA ELLEN.
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Contributor
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Arthur Boothroyd
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Date
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1987
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Language
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English
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Publisher
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City University of New York.
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Subject
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Health Sciences, Audiology
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Abstract
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Fundamental voice frequency (Fo) has been shown to be a highly effective supplement to speechreading when presented by hearing. When the same information is presented via the sense of touch, however, it provides only a small improvement of speechreading performance. The purpose of this study was to test the hypothesis that the poor performance of tactile Fo supplements is the result of degradation of fundamental frequency contours. This degradation results either from the inherently poor frequency resolution of the skin in single channel, temporal displays, or from the quantization that results from the use of discrete transducters, in multichannel, spatial displays.;Data were obtained for the recognition of words presented in sentence length stimuli by 12 normal adult subjects by speechreading, with and without auditory supplements. There were 5 supplements: (a) full Fo contour, (b) the Fo contour quantized at one, four, eight, and twelve levels. Performance under all supplemented speechreading conditions was found to be significantly better than performance by speechreading alone. The most effective supplement was the full Fo contour. Quantization at twelve levels resulted in a significant decrease of effectiveness. Supplemented speechreading performance diminished, in a monotonic fashion, as the number of quantization levels was further decreased. It was also found that sentence length was a significant factor determinant of performance in all conditions except speechreading + full Fo.;In the main experiment, the full Fo contour consisted of the output of an electroglottograph. In order to generate the quantized signals, however, it was necessary to extract and measure Fo, and to regenerate sine wave copies. In a supplementary experiment, it was found that the processing itself resulted in a marked loss of effectiveness, even before quantization was deliberately introduced.;The principal conclusion is that spatial tactile Fo displays should provide more than 8 levels of quantization if they are to be maximally effective.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Speech and Hearing Sciences
