A High Efficiency, Wide Band Sound Projector for Acoustic Tomography and Global Ocean Monitoring

An acoustic projector suitable for long range signaling in the ocean is described. The design employs a novel approach, which could result in projectors of high performance, high efficiency, operation at any depth, and substantially reduced cost. Resolution of short pulses fundamentally requires acoustic energy spread over a broad band. Traditionally this has been done with projectors that perform well over the band of interest; however, this has led to costly designs for frequencies <= 250 Hz. A projector designed for a specific family of codes isdescribed. Starting with a simple, high efficiency, narrow band design, the system of energy storage in the projector is slowly and controllably changed, permitting an FM sweep over a broad band, that is, the required broad band is achieved by controlled and continuous tuning of a high efficiency narrow band projector. A prototype of the basic projector, without tuning, has been built and the performance is measured. A program for adding the tunable capability is proposed for Phase I as well as a digital simulation of the projector equivalent circuit to verify input/output amplitude and phase tracking.