Abstract: A method and apparatus are described for holographically generating visual representations of acoustical characteristics of sound sources. A planar array has a lattice of microphone receiving points are disposed such that evanescent wave energy from the sources is detected along with propagating wave energy. The microphone outputs are sampled, resolved into phase and amplitude components, digitized and subjected to fast Fourier transform operations to provide computer graphic display means with holographic reconstruction parameters corresponding to the sources under analysis.

Abstract: A device for producing a varying frequency sine wave synthesized so that frequency is swept linearly with time for use in a continuous transmission FM sonar. A crystal clock, divider and a 16 bit digital output sweep counter produce 2.sup.16 counts for each sweep period T.sub.s. The 2.sup.16 counts are applied to a 16 bit digital to analog converter to provide a highly linear voltage ramp (the smoothed result of 2.sup.16 steps). The ramp is converted to a proportional frequency which is applied to a 5 bit digital counter to access a read only memory programmed to provide a digital output representing points along a sine wave. The memory output is applied to a digital to analog converter to produce a voltage output that is a 32 stepped approximation of a sinewave at a frequency which increases betweeen f.sub.1 and f.sub.2 with the linearity of the ramp voltage. A filter smoothes the output.

Abstract: A multiple channel cathode ray tube video display provides for adjusting brightness of the displayed channel by a single input control, such a trackball or keyboard, to a computer that generates a channel coded binary word that is held in one of a plurality of memory latches, each corresponding to a channel. The binary word is converted to an analog brightness signal that controls the gain of a corresponding one of a plurality of video signal amplifiers.

Abstract: A coil device for use by divers in subjecting an elongate underwater strure member to a magnetic field for inspection purposes includes a framework supporting a winding having first and second coaxial coils of predetermined coil diameter that lie in substantially parallel planes separated axially by a distance at least twice the coil diameter, the coils being electrically connected in series so as to generate magnetic fields of opposite polarity. The coils, connecting conductors, and framework are adapted to be spread open and closed around the member to be inspected.

Abstract: A pit depth gauge for use as an accessory to an underwater ultrasonic probe omprises two resiliently biased, freely flooded telescoping members a first of which has a first end wall adapted to ride on a surface to be inspected and a second of which has a second end wall adapted to be connected to the probe with the probe transducer in registration with an acoustic energy port. A stylus is fixed to the second member for axial movement with the transducer toward the first end wall as the stylus enters a pit, whereby the length of an acoustic water path is related to the pit depth.

Abstract: A missile thrust vector control system using fixed valves and nozzles in n numbers, as 4 or 8, mounted so that the thrust vectors operate at preselected angles to the frame and are pulse modulated in certain combinations to produce thrust vectors the sums of which provide desired deflections in pitch, yaw, and roll, without altering axial propulsion thrust.

Abstract: A rotary shaft position measurement system using digital position detectors roviding coarse and fine binary word readouts having four overlapping bits all of which are having subtractively compared to provide command signals that are used to correct the non-overlapping portion of the coarse word prior to combining with the fine word. The comparator utilizes a binary four bit full adder in combination with coarse word input inversion, and direct and inverted application of the carryout and .SIGMA.4 outputs to first and second AND gates to generate coarse word correction commands.

Abstract: A sheath device for heating breathing bags and hoses of underwater breath apparatus employs a fabric enclosure for the breathing bags, walls of which enclosure are formed of two layers sealed together at a plurality of discrete points to define water passages within sealed boundary lines. Tubular water conducting enclosures for the breathing hoses are connected to the enclosures in communication with the water passages in the walls, and flexible tubular dams connected to the device and to the hoses direct water flow from the wall passages into the hose enclosures.

Abstract: A diving suit is provided with neck and wrist opening seals each in the f of a right cylindrical annulus of open celled resilient foam rubber having a through passage a portion of which is cylindrical and a portion of which is frustoconical so that part of the annulus wall is of uniform thickness and part is tapered. The tapered portion overlies a conical, opening defining edge portion of the suit fabric and a band of non-stretch tape fixes the tapered edge portion of the annulus to the fabric while allowing the thicker wall portion to expand and contract as a head or hand is pushed through. The outer cylindrical surface beyond the tape is adapted to cooperate with a mask hood or glove cuff.

Abstract: A carbon dioxide scrubber device for use in a closed or semi-closed breatg gas circuit in an underwater breathing apparatus having a low rate of gas flow includes a canister having a plurality of spaced, coaxial walls that are heated by associated helical water flow heat exchangers and define axial gas flow chambers in which particulate carbon dioxide absorbent material is confined in contact with the heated walls. The heat exchangers are served by common supply and drain lines through water flow controlling connectors having flow dividing and uniting orifices.

Abstract: A bistatic, Doppler sonar that having a plurality of receiver channels det intrusion in an insonified water zone processes return signals in a plurality of discrete up Doppler and down Doppler frequencies to effect short and long term averaging of return energy and short and long term averaging of return energy slope prior to sampling and comparison to generate a multiple bit binary word that is periodically updated and read out in parallel form to detection logic. The detection logic utilizes parallel sets of shift register memories and comparators to detect when rates of occurrence of energy, slope, and stroke conditions exceed predetermined rates, and utilizes a plurality of levels of coincidence gates to detect predetermined combinations of such conditions that will produce an alarm initiating signal.

Abstract: A modular oven device for baking rewound and varnished electrical components of substantial size includes front and rear oven sections, sized to pass individually through a passageway too narrow to accommodate the component to be baked, and assembled on a base section to define an oven cavity, and a heater/blower section assembled on one oven section. The oven sections are characterized by double, unsulated walls, flanges covering joints, a thermostatic control, and inlet and exhaust air flow regulation.

Abstract: A retractable pad-eye device for use in association with a plate-like wall aving an opening includes a closure member for the opening and a pad-eye member, each connected by a jack-screw to a pivot-block that is rotatable mounted relative to the wall. By operation of the jack-screws with a wrench and rotation of the pivot-block, the closure member and the pad-eye member can be alternatively shifted between retracted or storage positions and operative positions in the opening.

Abstract: Cooling of electronic components on a circuit board is accomplished by a rmally conductive element such as a heat pipe that is in spaced parallel relation to the board and in contact with the upper surfaces of the components. The ends of the conductive element are forced into contact with a heat receiving and dissipating frame by a clamp device acting through the board and a lightweight spacer between the board and the conductive element.

Abstract: A diffuser and baffle device prevents sea water intrusion or ingestion into marine gas turbine engine exhaust system without significantly increasing exhaust back pressure. Inboard and outboard rows of vertical turning vanes are separated by a gap and effect successive bends of the exhaust flow in opposite directions while affording an increase in cross-sectional area. The outboard vanes are slotted at their inboard edge portions, and the inboard vanes are provided with hook-shaped projections defining grooves, whereby water driven into the device is arrested and drained overboard.

Abstract: A torque balanced cable for towing or suspending oceanographic instrumenton includes a data transmission core about which is wound a helically laid inner layer of load bearing strands formed of high tensile strength, low stretch aramid fiber and having a selected pitch angle, pitch diameter and strand thickness. An outer composite layer is contrahelically wound about the inner layer and an interposed, abrasion resisting barrier film layer, and includes alternating load bearing strands and non-load bearing filler strands, the other load bearing strands having the same degree of pitch angle and thickness as the inner strands and of a number that bears substantially the same ratio to the number of inner strands as the pitch diameter of the inner layer bears to the pitch diameter of the outer layer.

Abstract: In an unmanned underwater instrumentation vehicle, travel to an assigned th and cyclical excursions between depth tolerances above and below that depth are effected by a mechanism that alternatively drops vernier weights by firing explosive release bolts and floods buoyancy chambers by firing explosive piercing cartridges.

Abstract: A linear acoustic array for use in oceanographic work in either a towed or a vertically suspended configuration utilizes a flexible cable in which strands are woven or braided into a tube, the strands of which can be separated sufficiently to insert a hydrophone and multiplexer assembly at each of a plurality of specified locations therealong. Each hydrophone and multiplexer assembly is adapted to be readily connected into or removed from a two wire system.

Abstract: A compass device for underwater use and having substantially no magnetic nature or influence utilizes three Hall effect generators in an array wherein two of the generators have their principal axes of magnetic response extending normal to one another and at 45.degree. to the axis of the third generator. The array is rotatable relative to a base carrying three lights and solid state analog logic circuitry for causing the lights to be variously lighted and extinguished to indicate a need to turn left, to turn right, or being on course.

Abstract: An inflatable boat having tubular side and bow forming sponsons spanned by hull bottom or floor structure including an upper inflatable floor superimposed on a lower inflatable floor, in combination with a rigid sectional keelson that is removably secured at a plurality of locations to each of the floors. Top and bottom walls of the inflatable floors are interconnected by drop stitches to limit distension to a uniform spacing when inflated.