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The analysis and realization of a st...

Larson, Gregg D.

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The analysis and realization of a state-switched acoustic transducer.

Record Type:	Electronic resources : Monograph/item
Title/Author:	The analysis and realization of a state-switched acoustic transducer./
Author:	Larson, Gregg D.
Description:	241 p.
Notes:	Source: Dissertation Abstracts International, Volume: 57-07, Section: B, page: 4659.
Contained By:	Dissertation Abstracts International57-07B.
Subject:	Engineering, Mechanical. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9636274
ISBN:	9780591020458

The analysis and realization of a state-switched acoustic transducer.
Larson, Gregg D.

The analysis and realization of a state-switched acoustic transducer. - 241 p.

Source: Dissertation Abstracts International, Volume: 57-07, Section: B, page: 4659.

Thesis (Ph.D.)--Georgia Institute of Technology, 1996.

In order to produce high amplitude, low frequency signals, an underwater transducer must generate a relatively large volume displacement. Since water exerts a large reaction force back on the transducer, "conventional wisdom" dictates that such a transducer would have to be a high Q resonant device and thus not be broad band. However, a transducer does not have to be broad band in the conventional sense to meet the requirements of communication and sonar systems. A transducer that is capable of switching between two discrete frequencies is adequate for communication and one that is capable of switching among several frequencies could produce the chirp signals commonly used in active sonars and provide frequency diversity. Ordinarily, a broad band transducer is needed to accomplish the frequency switching rapidly.

ISBN: 9780591020458Subjects--Topical Terms:

783786
Engineering, Mechanical.

The analysis and realization of a state-switched acoustic transducer.
LDR:03269nmm 2200313 4500 001 1822834
005 20061128080145.5
008 130610s1996 eng d
020 $a 9780591020458
035 $a (UnM)AAI9636274
035 $a AAI9636274
040 $a UnM $c UnM
100 1 $a Larson, Gregg D. $3 1911964
245 1 4 $a The analysis and realization of a state-switched acoustic transducer.
300 $a 241 p.
500 $a Source: Dissertation Abstracts International, Volume: 57-07, Section: B, page: 4659.
500 $a Director: Peter H. Rogers.
502 $a Thesis (Ph.D.)--Georgia Institute of Technology, 1996.
520 $a In order to produce high amplitude, low frequency signals, an underwater transducer must generate a relatively large volume displacement. Since water exerts a large reaction force back on the transducer, "conventional wisdom" dictates that such a transducer would have to be a high Q resonant device and thus not be broad band. However, a transducer does not have to be broad band in the conventional sense to meet the requirements of communication and sonar systems. A transducer that is capable of switching between two discrete frequencies is adequate for communication and one that is capable of switching among several frequencies could produce the chirp signals commonly used in active sonars and provide frequency diversity. Ordinarily, a broad band transducer is needed to accomplish the frequency switching rapidly.
520 $a The objective of this research was to investigate a novel idea in the design of a high power, low frequency, broad band transducer for use in long range underwater communication, active sonar, and underwater research applications. The approach taken was to develop a realization of the "state-switched" source originally proposed by Walter Munk (Munk, Webb, and Birdsall, 1980, 1981).
520 $a It is theoretically possible to instantaneously switch frequencies with a high Q resonant system provided that the resonant frequency of the system is altered along with the drive frequency. Moreover, it is possible to accomplish the switching without having to provide additional energy to the system. Such a "state-switched" transducer retains the advantages (high power, high efficiency, and large displacements) of a high Q resonant transducer without the accompanying disadvantages (narrow bandwidth and slow response time). Higher source levels and increased bandwidth improve the accuracy of arrival time measurements for underwater research and active sonar systems.
520 $a State switching has been demonstrated with an acoustic transducer in air and water at frequencies between 725 and 1025 Hz. The state switched acoustic transducer, a tonpilz transducer with the addition of an active spring of piezoelectric ceramic, provides an efficient method of changing the resonance of the transducer by greater than 25% through control of the electrical boundary condition of the piezoelectric elements of the active spring.
590 $a School code: 0078.
650 4 $a Engineering, Mechanical. $3 783786
650 4 $a Physics, Acoustics. $3 1019086
690 $a 0548
690 $a 0986
710 2 0 $a Georgia Institute of Technology. $3 696730
773 0 $t Dissertation Abstracts International $g 57-07B.
790 1 0 $a Rogers, Peter H., $e advisor
790 $a 0078
791 $a Ph.D.
792 $a 1996
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9636274