Furuno Electric Company Limited

Ryouichi Suetoshi

Yasushi Nishimori

Takeharu Yamaguchi

Koji Tokuda

Kouzo Tokuyama

Kenichi Watanabe

Kazuhiko Kamei

The invention provides a multi-frequency transducer capable of obtaining desired directivity regardless of frequencies. Parallelepiped-shaped transducer elements () are used as transducer elements and a plurality of such transducer elements () are arranged in an array. The transducer elements () are caused to resonate using a resonant frequency in fundamental vibration mode and a resonant frequency in harmonic vibration mode determined by the dimensions (A, B) of a short edge () and a long edge () perpendicular to a longitudinal edge () of each transducer element () to transmit and receive at multiple frequencies. The angle of directivity (&#x3b8;) of the transducer elements is controlled by the dimension (C) of the longitudinal edge which is set to a value which does not affect resonance in either the fundamental vibration mode or the harmonic vibration mode.

Multi-frequency transmission/reception apparatus

An acoustic transducerhas a first cylindrical portionA and a second hemispherical portionB on which a plurality of transducer elementsare arranged. The transducer elements on the cylindrical portion are arranged to have six nearest neighbors. The arrangement may be such that the six transducer elements surrounding a given element describe the vertices of a regular hexagon. The hexagons thus described may be aligned so that two of their sides are parallel to the axis of the cylinder. The elements on the hemispherical portion may be arranged so that some elements have five nearest neighbors and others have six (the neighboring elements describing, for example, the vertices of hexagons and pentagons respectively). An underwater sounding apparatus may be constructed using the transducer.

Acoustic transducer and underwater sounding apparatus

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Amagasaki, Japan

Ryouichi Suetoshi