Howse, Everett Dwight (1981) A digital acoustic underwater communication system. Masters thesis, Memorial University of Newfoundland.
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There is a need for an underwater communication system capable of reliable data transmission at rates in excess of 10³bps. Such a system would have applications in controlling unmanned tetherless submarines or in transmission of slow-scan television pictures through the ocean. The main hinderance to the development of reliable data transmission through water, using acoustic propagation is the multipath interference caused by reflection and refraction in the ocean channel. The effects of multipath may be suppressed using a swept carrier modulation technique. -- A prototype swept carrier system using a ramp type of sweep has been designed and built. This system is designed to provide a bandpass channel of reduced multipath which may be used for either analog or digital transmission. The prototype is designed to transmit a 2 kHz message through the ocean by amplitude modulating a swept carrier. Laboratory test using a carrier which is swept from 20 kHz to 40 kHz with a 500 ms repetition rate indicating that this type of system is capable of suppressing the multipath effects. Tests conducted at sea identified a need for modifications which are required before the prototype can be developed into a full-scale undercover acoustic communication system.
|Item Type:||Thesis (Masters)|
|Additional Information:||Bibliography: leaves 97-102.|
|Department(s):||Engineering and Applied Science, Faculty of|
|Library of Congress Subject Heading:||Underwater acoustics; Acoustical engineering|
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