Abstract: An acoustical sensor utilizing fiber optic transmission including an optical signal generator, a first single-fiber transmission line connected to the generator, and a coupler for receiving signals from the first line and transmitting the signals to a second single fiber which directs the signals to an acoustically sensitive reflective surface. The surface modulates the signal in accordance with acoustical signals applied to it and reflects at least part of the signal back to the fiber where it is transmitted to a third fiber by the coupler and then transmitted to an electronic receiver.

Abstract: A pressure sensitive line transducer wherein electrical signals are generd by the modulation of the electrical resistance of a coaxial cable due to pressure variations because of an impinging acoustic wave. The signals are extracted via a step-up transformer, amplified, filtered and processed by a computer and displayed to extract information about the acoustic wave.

Abstract: 1.

Abstract: 1.

Abstract: 1. A vessel detecting apparatus comprising means responsive to the time ving negative pressure signal produced by the passage of a vessel in proximity to the detecting apparatus for producing an electrical signal having a time varying amplitude correlative with the square root of pressure signal, means for integrating said electrical signal over the interval of the negative pressure signal duration, and utilization means responsive to the time integral of said electrical signal.

Abstract: A fiber optic hydrophone for use as an underwater electroacoustic standard. The hydrophone includes a fiber optic acoustic wave detector in one end of the hydrophone which is subjected to incident acoustical waves. A similar fiber optic is in an acoustically isolated compartment where the optic fiber is not affected by the incident acoustical wave. Comparison of light passing through each coil will determine incidence of an acoustical wave on the detector fiber.

Abstract: 8.

Abstract: An acoustic line array which includes a co-axial cable having a center coctor surrounded by a flexible material of low-electrical conductivity. The flexible material is surrounded by a conducting material protected by an external shield. The cable has characteristic impedance which is sensitive to pressure variations in the medium due to a traveling acoustic pressure wave from an acoustic source. Variations in the impedance of the array are used to detect the acoustic source. Alternatively, the line array makes use of discrete sensors placed at suitable intervals along the array. This type of acoustic array eliminates the use of a plurality of wires carrying the electrical signals from the transducer to the storage equipment and elaborate multiplexing techniques.