Abstract: A connector holder assembly for use with a wiring harness wiring has a frame adapted to hold a connector contained with the frame by a snap-on cover. A pair of jackscrews secures the frame to a mating connector. The frame is cast with two arms at each end of a back plate. The arms have inboard slots for receiving jackscrews. The jackscrews are retained within the slots by a connector which has detents at its ends which engage the jackscrews when the connector has been positioned between the jackscrews. A stiff spring-like metallic retainer cover for the connector which is snap fastened to the arms of the frame retains the connector between the frame arms and against the backplate of the frame against the force produced on the connector by the wiring harness attached thereto.

Abstract: A solid state transmit/receive switching circuit is provided by a system which, in accordance with the invention, comprises a solid state relay which, when energized, causes an optically controlled resistor connected to an input terminal of a preamplifier of the receiver to change its resistance and hence the sensitivity of the preamplifier according to the transmitter transmission state.

Abstract: The transmission system of this invention provides for transmitting over a fiber-optic line serially sampled analog data from a plurality of channels. Each sampled analog signal has a interleaved digital pulse. A sequence of digital pulses provides synchronization data for the determination in the receiver of the output channel for each received sampled analog signal. The digital pulse associated with each sampled analog signal provides the timing for a sampling circuit to provide as an analog signal each of the sampled analog data as an analog signal to a separate channel. The digital pulses not needed for synchronization are used for digital data transmission.

Abstract: A sonobuoy depth selector utilizes the tension in the attaching cable between the suspended sonobuoy and the supporting float to select the length of the attaching cable. Bobbins are attached to the cable at predetermined distances from the float. The bobbins are also mounted on a solenoid actuated pin which is tapered to cause only the bobbin resisting the tension in the cable to slide along the pin to a release position near the end of the pin. Momentary electrical energization of the solenoid causes the pin to release only the bobbin under cable tension thereby allowing the cable to pay out from a cable reel until stopped by the bobbin attached to the next larger predetermined length of cable.

Abstract: A circuit board holder and module including the circuit board and holder are described wherein a cover plate integral with the holder is in thermal contact with the heat producing elements mounted on the circuit board. The heat generated in the elements is transferred through the cover plate to the peripheral portions of the holder where the holder is in contact with a heat sink.

Abstract: A rod of magnetostrictive material has its ends placed between steel bars which provide compression on the rod by tensioning wires connected between the bars. Preferably, the wires are equally spaced along the bars from the rod so that when the wires are equally tensioned the rod is under no bending stress. The tension of the wires (and from this value, the compression of the rod) is conveniently determined by the freqency of vibration of the wires using known physical relationships between these quantities.

Abstract: A crossed-field amplifier tube with a cathode slow wave structure at a high electrical potential is coupled to a high frequency of source and a load by a direct current isolated radio frequency transition. The transition is contained within the vacuum of the tube to prevent electrical breakdown between the transition and ground.

Abstract: An ultrasonic transducer and its method of fabrication wherein bonding between an impedance matching layer on one side of a piezoelectric layer and a support layer on the other side of the piezoelectric material is made by providing onto each material a smooth, thin gold film on the smooth surfaces of the layers which are to be in contact with one another in the assembled transducer. The layers are bonded to each other by the gold films under moderate temperature and pressure to form the transducer. Sawing of the impedance matching and piezoelectric layers into a plurality of parallel transducers attached to the support layer forms an array.

Abstract: A divider/combiner amplifier circuit divides input power through a sectored coaxial line to a plurality of longitudinal parallel channels spaced around the circumference of a cylinder; the power in each channel is amplified by a semiconductor device; and the amplified power is combined in another sectored coaxial line. A microwave waveguide connected to the input and output of each amplifying device confines the microwave energy of the operating mode to the longitudinal channel formed by said waveguide. Each waveguide extends longitudinally along the cylinder and each is circumferentially spaced from its neighboring waveguide by a space which forms a cut-off waveguide to the operating mode.

Abstract: A latching mechanism for retaining the cover of the compartment of a sonobuoy containing a parachute is described. The latching mechanism, when in a position which prevents the deployment of the parachute, extends beyond the periphery of the sonobuoy launching tube and thus prevents insertion of the sonobuoy into the launching tube. The latching mechanism must be moved to a position which releases the cover before it allows insertion of the sonobuoy into the launching tube thereby insuring deployment of the parachute after the sonobuoy has been ejected from the launching tube. The latching mechanism is a planar structure rotatably connected to the cover and rotates in a plane parallel to that of the plane of the cover. The resulting latching mechanism may be applied to sonobuoys without the necessity for modifying the launching tube structure used for prior art sonobuoys.

Abstract: A divider/combiner amplifier circuit divides input power through a sectored coaxial line to a plurality of longitudinal parallel channels spaced around the circumference of a cylinder; the power in each channel is amplified by a semiconductor device; and the amplified power is combined in another sectored coaxial line. A microwave waveguide connected to the input and output of each amplifying device confines the microwave energy of the operating mode to the longitudinal channel formed by said waveguide. Each waveguide extends longitudinally along the cylinder and each is circumferentially spaced from its neighboring waveguide by a space which forms a cut-off waveguide to the operating mode.

Abstract: A sonar system for the detection of signals reflected from a sloping ocean bed in which a sample of the transmitted signal is modified to correspond to the received signal as modified by the sea bottom before both signals are applied to a correlation detector. Modification of the transmitted signal sample is provided by summing incrementally delayed portions of the transmitted signal sample.

Abstract: A suspension system for an air-dropped sonobuoy includes a transducer housing wherein the upper portion is emptied upon deployment of a float. The weight distribution of the transducer and housing provide for a center of mass and a center of buoyancy at a location beneath a pivot in the upper portion of the housing. A suspension line connects the pivot with the float, and a pair of opposed extensible fins at the top of the housing locate the center of hydrodynamic pressure at the pivot. Thereby, the housing is maintained in a stabilized vertical attitude during descent through the water and during deployment at a predetermined depth independently of a difference in velocity of fluid movement at the float and at the sonobuoy.

Abstract: A method including a novel bath is described for the nickeling of the aluminum pads of a chip, when either in die form or in wafer assembly. A near-neutral pH immersion zinc bath is used to cover the aluminum with zinc, which is followed by immersion in an electroless boron-nickel solution for nickeling of the zinc. The method eliminates the need to isolate the chip silicon from the plating bath.

Abstract: A system of slow wave structures for coupling a first electromagnetic circuit to a second electromagnetic circuit includes an inner slow wave structure and an outer slow wave structure concentric with the inner structure. The outer structure is configured to provide for a greater phase velocity of electromagnetc waves than the inner structure, the phase velocities for each structure being proportional to the circumference of each structure so that the rate of circulation of a wavefront about the common axis of the two structures is the same for a wave propagating about the inner structure and a wave propagating about the outer structure. The structures are terminated in their characteristic impedances to provide for wave propagation in one direction without reflections.

Abstract: A lined duct is divided into two parallel branches by means of a rigid partition. The phase speed of the fundamental mode in each branch depends on the liner configuration and can differ markedly from the free-space phase speed. When the liners in the two branches are not the same, the corresponding phase speeds will be different and a relative phase lag between the waves in the two branches results. This, in turn, leads to interference between these wave components (and their reflections) both at the exit and entrance of the parallel branch pair. This interference can be exploited for the purpose of obtaining a low-frequency attenuation which is substantially larger than the attenuation of the unpartitioned duct.

Abstract: An imaging system, particularly useful for acoustic medical diagonsis of a human subject, utilizes an array of radiating elements or sonic transducers located side-by-side and positioned along the subject. Signals received by the transducer are applied to a pair of pattern generation circuits which weight the individual signals by factors of +1, -1 or 0. Graphs of the weighting factors as a function of transducer location have the likeness of cosinusoidal and sinusoidal Fresnel patterns, these patterns being produced by the two circuits. Upon reception of signals, the weighted signals of each pattern are summed together, multiplied by cosinusoidal and sinusoidal reference signals and then summed together to provide a radiation pattern which converges from the array to a focal point in front of the array while eliminating a diverging pattern from a virtual focus behind the array.

Abstract: A selective-black absorber capable of operation at elevated temperatures and high efficiency as a solar energy absorber is described. A cermet of MgO/Au, MgO/Pt, and Cr.sub.2 O.sub.3 /Cr having high solar energy absorptance and low infrared energy emissivity is coated on a substrate having high infrared reflectivity such as Mo coated on stainless steel; Ni coated on Cu, or steel; aluminum, or steel. Typically an absorption coefficient of about 0.93 with an emissivity of about 0.09 is obtained and operation at a temperature of 300.degree.-400.degree. C. is possible depending on the cermet and substrate materials.

Abstract: A buoy flotation system, wherein a container of a compressed fluid is utilized for expansion of a float, includes a cutter for severing and removal of a portion of the container for releasing the compressed fluid. The cutter includes a piston having a recess in a side wall thereof for mating with the container, the piston being contained within a housing, the piston and the housing having cutting edges. An explosive charge drives the piston transversely of the container whereupon the cutting edges sever and remove a portion of the container for evacuation of the compressed fluid therefrom.

Abstract: A window for a sonar transducer housing is formed of an elastomeric plate which is bonded to a mounting ring for securing the window to the housing. The plate is bowed with a convex shape during the molding and the curing of the elastomer. During assembly of the housing, the convex surface of the plate faces inwardly and is depressed to a substantially planar configuration by the pressure of oil within the housing. The compression of the elastomer against the mounting ring inhibits separation of the elastomer from the ring.