1. Field of the Invention
This invention relates to a compact, lightweight device to produce high-power acoustic signals of relatively low frequencies in water.
2. Description of the Related Art
Acoustic devices used to produce high-power, low-frequency sound in the ocean are characterized by their large size and weight. It is desired to be able to generate hundreds of watts of omnidirectional acoustic power at frequencies below 1000 Hz with a device that can be deployed from an aircraft, surface vessel, or submarine. Although conventional low-frequency sources can usually operate over a broad band of frequencies, there exists a definite desire for a compact device with more limited bandwidth which could be assembled in modular configurations of units with different frequencies to meet frequency spectrum requirements.
In order to create high-power acoustic tones in water at low frequencies (below 1000 Hz), a device must produce large volume displacements. The volume displacement is the integral of the normal displacement of a radiating area, taken over that area. Therefore, an acoustic source must either have a large radiating area, a large displacement, or a combination of both.
In order to be effective for such applications as anti-submarine warfare and undersea geological surveying, a transducer must be operable at a wide variety of ocean depths, including great depths of several thousand feet. It is also desired to have such a transducer with an output that varies linearly with the transducer input.