David Marschik

Apparatus for transmitting two frequency signals with an acoustic projector

An acoustic projector wherein a unitary acoustic resonator produces active sonar signals in more than one frequency band. The double-slotted resonator is coupled to a transducer which is capable of exciting the resonator in two, distinct, volumetric modes of vibration using two asymmetric, generally arcuate vibrating members. Transduction techniques can include variable reluctance or piezoceramic transduction. Internal cavity pressure release may be achieved by bladders, compliant tubes, and the like.

Variable reluctance acoustic projector

A variable reluctance acoustic projector includes a piston structure that provides rigid retention and precise alignment of electromagnetic cores within the projector housing. The piston structure provides a pair of metallic piston blocks having cavities in which the electromagnetic cores are mounted. The piston blocks rigidly retain the electromagnetic cores within the cavities by compressive loading, improving the structural reliability of the device. In addition, the piston blocks enable precise alignment and orientation of the pole faces of opposing electromagnetic cores parallel to one another. Flexure ribs formed in the piston blocks increase the compliance of the blocks to substantially confine motion of the piston blocks to translation along a single axis of actuation during excitation of the electromagnetic cores.