Abstract: An acoustic baffle for reflecting sound waves and rejecting background interference noise for use with a hydrophone array. The baffle utilizes a plurality of lenticular resilient elements embedded in a compliant foam elastomer compound. The embedded elements provide control of overall baffle compliance for submarine applications, particularly for high hydrostatic pressure operation. The resilient members are formed from pairs of resilient lenticular shaped elements which are integrally bonded to a highly damped constrained viscoelastic layer to provide uniform noise reduction performance over a broad frequency range. The pairs of elements are joined at their ends by compliant end caps which provide minimum constraint on the motion of the ends, thus limiting bending stresses in the elements.

Abstract: An element responsive to acoustic particle acceleration for sensing acoustic signals in a region of low acoustic pressure is disclosed. The element may be isolated from acoustic noise when positioned adjacent an acoustic noise generating high acoustic impedance structure by a baffle which provides isolation from radiated and evanescent acoustic signals and structure vibration.

Abstract: An element responsive to acoustic particle acceleration for sensing acoustic signals in a region of low acoustic pressure is disclosed. The element may be isolated from acoustic noise when positioned adjacent an acoustic noise generating high acoustic impedance structure by a baffle which provides isolation from radiated and evanescent acoustic signals and structure vibration.

Abstract: An apparatus for determining an angle of incidence of a received signal utilizes two widely spaced interferometers with equal length crossing baselines. The time differential of a signal arrival between the two elements of each interferometer is established and the difference between the two time differentials is determined. Multiplying this difference by a predetermined constant provides the desired angle.

Abstract: A sonar array wherein the capacitance associated with the hydrophones of the array are utilized as shunt elements in an artificial transmission line in order to form an acoustic beam. Series inductance elements to the transmission line are variable with d.c. current flowing through coils wound about a magnetic core about which coils forming the series inductance of the line are also wound, thus permitting the sonar beam to be steered to any desired position.

Abstract: A parallel digital beam-former for an array of hydrophones. The output of ch hydrophone is fed into a different shift register. Each register stores the sampled time history of the hydrophone. The contents of each register are fed serially into a different gating circuit in the time interval between each new input signal sample and the output of each gating circuit is fed in parallel with the output of each of the other gating circuits to a group of beam gates. The output of each beam gate is then fed to a different binary counter which sums the signals. Each binary counter is associated with a different beam.