• The Journal of the Acoustical Society of Korea
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• v.38 no.3
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• pp.256-265
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• 2019

Several types of cymbal transducers used for underwater detection have been studied. Representative types are Moonie, convex cymbal, and concave cymbal transducers. In this study, we analyzed the characteristics of these three types of transducers for underwater broadband projectors and compared them together. First, the influence of structural variables on the acoustic characteristics of the transducers was analyzed. Based on this, we derived the structure of each transducer type to have a specific center frequency and the maximum bandwidth. As a result of comparing the performance of the optimized transducers, the convex cymbal transducer turned out to be best in terms of both broad bandwidth and high power.

• The Journal of the Acoustical Society of Korea
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• v.39 no.3
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• pp.170-178
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• 2020

Cymbal transducers are often used as an array rather than single because they have a high quality factor and low energy conversion efficiency. When used as an array, there occurs a big change in the frequency characteristics of the array due to the interaction between constituent transducers. In this study, we designed the structure of a cymbal transducer array to have ultra-wideband characteristics using this property. First, cymbal transducers with specific center frequencies were designed. Then, a 2×2 planar array was constructed with the designed transducers, where the cymbal transducers were arranged to have same or opposite polarization directions. For this structure, we analyzed the effect of the difference in the center frequency of and the spacing between the constituent transducers on the acoustical characteristics of the array. Based on the analysis, we designed the structure of the cymbal transducer array to have the widest possible bandwidth.

• The Journal of the Acoustical Society of Korea
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• v.40 no.1
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• pp.10-17
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• 2021

The cymbal transducer is a miniaturized version of the Class V flextensional transducer. It has low resonant frequency and high output pressure characteristics compared with its size. However, since it has high quality factor and low energy conversion efficiency as well, it is often used as an array rather than single. When used as an array, a big change in the frequency characteristics occurs in comparison with that of the single transducer due to the interaction between constituent transducers. In this study, we designed a pattern of cymbal array with a view to having broadband characteristics. Three transducers having different center frequencies were designed first. The designed cymbal transducers were used to construct all possible patterns of a 3 × 3 planar array. After analyzing frequency characteristics of these patterns, based on the results, we derived the most effective pattern to achieve a higher fractional bandwidth. The derived array pattern showed an improvement of the fractional bandwidth by 24.9 % in comparison with the reference model.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.401-404
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• 2004

수중음향통신 관점에서 바다와 같은 수중채널은 수십심벌에 이르는 다중경로와 빠르게 변화하는 도플러 효과가 존재한다. 따라서 신뢰성 있는 수중음향통신을 위해서는 채널 등화가 반드시 필요하다. 본 논문에서는 이차 통계량 기반의 Blind Identification 알고리듬을 이용한 수중음향 채널추정 기법을 이용하여 무향수조의 채널응답을 분석하였다. 실험을 통하여 알고리듬의 추정 정확도 및 트랜스듀서 특성을 포함한 무향수조의 채널 응답 특성에 대하여 논한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.318-318
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• 2010

In this paper, we studied generating characteristic of cymbal type piezoelectric transducer according to change of cymbal cap. The transducer is composed of circular piezoelectric ceramic and two elastic bodies which are shaped as cymbal. Two elastic bodies are attached to upper and bottom of the ceramic. Principle of the transducer is to generate expanded displacement because vertical stress is transformed into horizontal stress by slope angle of elastic bodies. The transducer also has advantage of high durability by the angle of elastic bodies. In this study, each parameter was chosen, and then generating characteristics were analyzed by FEM program. The parameters were slope angle of cymbal cap (theta), cap height (h) and cap inner diameter(d). The model that had generating characteristic Of high voltage was chosen by results of the analysis. Besides, maximum vertical displacements according to change of vertical stress were analyzed by structural analysis in order to find out relation between the maximum vertical stress which can prevent from ceramic damage and conditions of each cap.