Abstract: The invention relates to acoustic transducers which comprise a ceramic ring formed from a pre-stressed set of segments. It consists in using, as screws for tightening pre-stressing wedges, screws with hexagonal heads and in placing on the inner face of these wedges a plate provided with recesses in which the cants of these screw heads become anchored. This plate comprises transverse channels allowing the passage of the power supply wires for the sectors. The central screw is removed after the desired pre-stressing has been obtained. It makes it possible to improve the manufacture of these transducers.

Abstract: The invention relates to acoustic transducers which comprise a ceramic ring formed from a pre-stressed set of segments.

Abstract: An underwater acoustic transducer configured to emit a low-frequency broadband acoustic signal. The underwater acoustic transducer includes a cap in the form of a cylinder closed on one side and open on the other side. A piezoelectric plate operating in flexion is fixed on the base of the cylinder outside the cylinder. The inside cavity defined by the cylinder is open freely toward the outside medium in which the acoustic waves are to be emitted. For identical dimensions, the underwater acoustic transducer makes it possible to decrease a central frequency of emission and to increase bandwidth.

Abstract: Acoustic transmitting antennas in the form of circular rings. Several circular rings which can be dismantled of a known type are superimposed in a stack. The stack is terminated at each end by two profiled annuli. The threaded tie-rods traverse the stacks of the pre-stressing keys of the rings by the intermediary of holes drilled in these keys. The threaded tie-rods make it possible to ensure the holding of the assembly. Two jackets, inside and outside, made of rubber, cover the inside and outside faces of the stack and are anchored in grooves formed in the profiled annuli. Thereby, annular transmitting antennas can be provided which can be dismantled entirely and whose active mass to inactive mass ratio is particularly large.