engleski

Sequential ultrasonic transducer for echo sounders on small and middle size vessels

The aim of the study was to evaluate the possibility to use both significant modes of piezoelectric disc vibration to acchieve permanent contact of ultrasonic beam with sea bottom or reefs below the wessel keel, where ultrasonic transducers are usually mounted. Starting with the theoretical analysis of piezoelectric element vibration in radial and thickness mode and with construction requirements for ultrasonic transducers, electrical, acoustical and hidroacoustical parameters on both characteristical frequencies have been compared. Having in mind that most of commercial-type echo sounders operate at the thickness-resonance frequency of the piezoelectric element and on the basis of results obtained, this paper has confirmed the practicability of using piezoelectric element vibration in the radial mode for acchieving longer measuring ranges, with reduced accuracy and resolution, but with receiving/transmitting sensitivity and horizontal/vertical directivity comparable to those of the thickness mode.

beam pattern; sensitivity; sonar equation; ultrasonic transducer

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