High-Fidelity Underwater Sound Transducers

Sims, Claude C.

doi:10.1109/jrproc.1959.287282

Cited by 6 publications

(4 citation statements)

References 2 publications

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“…22 It is apparent from examination of Figs. 8,9,15, and 16 that the ''effective bandwidth'' is larger than the frequency separation of the two resonances.…”

Section: Advantages Of State Switchingmentioning

confidence: 97%

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State switched transducers: A new approach to high-power, low-frequency, underwater projectors

Larson

Rogers

Munk

1998

The Journal of the Acoustical Society of America

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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 broadband. However, a transducer does not have to be broadband in the conventional sense to meet the requirements of communication and sonar systems. A transducer that is capable of instantaneously switching between two discrete frequencies is adequate for communication and transmission of coded signals; one that is capable of switching among several frequencies could produce the chirp signals commonly used in active sonars. Ordinarily, a broadband transducer is needed to accomplish the frequency switching rapidly. A way around this difficulty is the ''state-switched'' source concept originally proposed by Walter Munk in 1980 which permits instantaneous frequency switching of a high Q resonant transducer while always maintaining the resonance state. The objective of this research has been to investigate this novel approach to the design of high-power, low-frequency, broadband transducers for use in long-range underwater communication, active sonar, and underwater research applications. This paper presents a practical realization of a ''state-switched'' source.

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“…22 It is apparent from examination of Figs. 8,9,15, and 16 that the ''effective bandwidth'' is larger than the frequency separation of the two resonances.…”

Section: Advantages Of State Switchingmentioning

confidence: 97%

“…The Q of the short circuit resonance is 56. 8 response of the transducer. Specifically, the response at resonance is substantially higher than the response away from resonance.…”

Section: State Switching Concept Demonstrationmentioning

confidence: 99%

State switched transducers: A new approach to high-power, low-frequency, underwater projectors

Larson

Rogers

Munk

1998

The Journal of the Acoustical Society of America

View full text Add to dashboard Cite

show abstract

“…Equations describing the output acoustic pressure from a circular piston at the end of a long tube in terms of electrical input parameters and as a function of frequency have been developed by Sims and others [1,2,3]. For a piston operating above the resonance frequency w 0 ' the transmitting current response measured at a distance of one meter may be represented by…”

Section: Ttmentioning

confidence: 99%

“…At most frequencies in the range under consideratin, calculation of the pressure generated at one meter can be simplified by setting the directivity factor in Eq, (6) equal to unity. A 1 In terms of the equivalent electrical circuit, the acoustic power T c i sgradiated by the piston is equal to the power dissipated in the radiation resistances N2/RR and N2/RR2' If an input current of 1 A is specified, the transmitting current response can be represented by p = (PRRPCOc/,a)…”

Section: (6)mentioning

confidence: 99%