Abstract: A frequency-tracking feedback circuit for acquiring a communication carrier signal from a relatively noisy environment. The circuit includes a digital phase-frequency detector, a limiter, a mixer, and a voltage-controlled oscillator, connected in a long control loop in such a manner that an input band of signals is translated in frequency until the desired carrier is centered within a relatively narrow acquisition window. The characteristics of the loop are such that acquisition may be achieved even when the total power of the noise in the input signal band exceeds the carrier power, provided that the noise is relatively uniformly distributed over the input band. A technique is also disclosed for compensating from any unbalance in the noise spectrum, so that relatively low carrier-to-noise ratios can be tolerated.

Abstract: Acoustic wave devices employing shallow bulk acoustic waves rather than surface acoustic waves, to provide higher frequencies of operation and other significant advantages, such as less susceptibility to aging and less sensitivity to surface contamination. In each embodiment of the invention, a transmitting transducer and a receiving transducer are oriented on the surface of an anisotropic piezoelectric crystal to achieve substantial coupling of shallow bulk acoustic waves and essentially zero coupling of surface acoustic waves. In one embodiment of the invention, various types of grating filters utilize shallow bulk acoustic waves, and a set of parallel mechanical or electrical discontinuities at or near the surface of the crystal provide reflection of acoustic energy at a frequency determined by the spacing of the discontinuities. Uniformly spaced gratings provide bandpass filter operation, and gratings with graduated spacings provide for frequency compression or expansion.

Abstract: A solar array having solar cells mounted on a substrate and electrically joined by rear connector elements on the substrate and front connector elements secured between the cells to the substrate is fabricated by placing the array components in assembled relation and utilizing induction heating to heat to their fusion temperatures a thermoplastic adhesive layer on the substrate and contacting fusible cladding on the solar cells and the connector elements while retaining the components in firm contact to effect adhesive bonding of the solar cells and front connector elements to the substrate and metallic bonding of the solar cells and connector elements to one another.

Abstract: Digital circuitry, and a corresponding method for its operation, for detecting frequency or phase-angle differences between two digital input signals. The detector includes a differentiating circuit to provide signals indicative of the times of occurrence of a selected feature of the input signals, such as a pulse edge, and a pair of memory devices, such as flip-flops, which can be set by respective input signals. The detector further includes a feedback circuit operative to clear both flip-flops in the event that the input signals would be effective to place both of them in a set condition. The feedback circuit operates in a parallel, rather than a series timing relationship with input circuitry that sets the flip-flops, and the performance of the detector is thereby significantly improved, as evidenced by a smaller dead zone in its phase output characteristic for a given frequency of operation, or a capability of operation at higher frequencies for a given degree of degradation.

Abstract: A method for making water-soluble potassium formate substantially free of water-insoluble salts selectively and in high yield at temperatures at or below about 100.degree. C., includes contacting potassium sulfate, potassium carbonate or a mixture of potassium and sodium carbonate and potassium and sodium sulfate with calcium formate, forming water-soluble potassium formate and water-insoluble calcium sulfate, calcium carbonate, or mixtures thereof, thus permitting recovery of substantially potassium-free calcium sulfate, calcium carbonate or both, and substantially calcium sulfate-free calcium carbonate-free potassium formate from the aqueous media.

Abstract: A mixture of at least two particulate metals capable of undergoing an exothermic reaction to form an intermetallic compound is provided to sustain decomposition of borane reactants to yield hydrogen or deuterium.

Abstract: A collapsible dish structure composed of a plurality of rows of rigid radial petal assemblies concentric with the axis of the dish. The petal assemblies consist of a center petal and two side petals, the center petal hinged on an axis tangent to a circle concentric with the axis of the dish and the side petals hinged to the center petal at their mating edge. The center petal is foldable inwardly and the side petals rotate about their hinges such that the collapsed dish structure occupies a much smaller volume than the deployed dish. Means of controlling the shape of the dish to compensate for differential expansion of the deployed dish are also provided.

Abstract: This invention relates to the distribution of electrical power to subsea petroleum recovery installations, and more particularly to methods and apparatus for sensing and limiting the electrical current drawn through power cables disposed on the sea floor. A transformer having primary winding and a secondary winding is located at a subsea power distribution module and has its primary winding connected in series with the power cable. A variable impedance device is connected to the secondary winding and is actuated, in response to a control signal indicative of the current drawn through the power cable, to substantially open-circuit the secondary winding when the current exceeds a predetermined value. Additionally, the variable impedance device substantially short-circuits the secondary winding when the load current falls to a level less than a preselected minimum value.

Abstract: A low distortion phase compensated wideband amplifier system includes a low cost, power efficient Class C amplifier positioned along a primary signal path and a feedback loop coupled to provide negative feedback of distortion signal components in the amplified output signal. The negative feedback significantly reduces noise components including intermodulation noise while variable delay phase compensation permits a greater signal to noise ratio over a broader band of frequencies at the system output.

Abstract: An electronic waveguide switch of a latching type particularly suitable for the microwave and millimeter range. The switch comprises a standard three port housing connected to three waveguides. A switchable junction ferrite is disposed in the center of the housing, the ferrite being of the latching type. A driver ferrite is disposed outside of the housing. All ferrite elements have a substantially cylindrical shape.

Abstract: A surface acoustic resonator including an interdigital transducer configured to generate acoustic waves at at least one harmonic frequency, and a pair of reflection gratings capable of essentially total reflection of the acoustic waves in both fundamental and harmonic modes of operation. One-port and two-port resonators are disclosed, capable of operation at fundamental and harmonic frequencies, to provide a higher frequency of operation without correspondingly higher resolution requirements for manufacturing processes. For single-mode operation at higher frequencies, the interdigital transducer and reflection gratings have different fundamental frequencies, and utilize harmonics of different order but the same actual frequency, such that the resonator functions at a single frequency, which may be, for example, the third harmonic with respect to the transducer fundamental frequency, and the second harmonic with respect to the reflection grating-fundamental frequency.

Abstract: A pressure stabilization and equalization device to prevent single wheel lock-up in hydraulic brake systems comprises a housing with openings adapted for connection to a hydraulic line between a power source and a pair of brake actuators. The openings communicate with a fluid receiving first chamber within the housing containing the exposed end face of a freely movable piston axially aligned with a shock absorbing, resiliently yieldable member that extends axially into but does not fill a second chamber formed by the housing. Hydraulic shock waves of increased pressure which occur within the first chamber because of an imbalance reaction from one of the brake actuators as the brakes are applied in a vehicle, are absorbed and damped out by movement of the piston against the resiliently, yieldable member which temporarily deforms within its chamber of the housing.

Abstract: Apparatus for equalizing pressure and absorbing shock to prevent single wheel lock-up in a pneumatic braking system including a pneumatic source coupled by air lines to two brake actuators and being subject to the presence of contaminants of the water droplet and particulate type, the apparatus comprising a walled housing including an inner surface forming an elongated cavity having a first port for connection to the pneumatic source and a second port for connection to one of the actuators, the cavity being configured to form a first chamber that communicates with the first and the second port and to form a second chamber, a rigid piston having a first end and an opposed second end, an elongated resiliently yieldable, shock absorbing member disposed within the cavity between the second end and an opposite wall of the cavity, the member having an outer surface and a transverse cross-sectional dimension less than the corresponding transverse cross-sectional dimension of the cavity such that the separated outer

Abstract: A process for epitaxially forming a layer of gallium arsenide having a first conductivity on a substrate of gallium arsenide having a second conductivity in an enclosure having an inner liner comprised of a silicon compound, comprising decomposing arsine to form arsenic; chemically reacting a first quantity of hydrogen chloride and gallium to form gallium chloride, the gallium chloride reacting with the arsenic to form gallium arsenide on the substrate, a portion of the first quantity of hydrogen chloride remaining unreacted and tending to cause silicon contaminants from the liner to be deposited on the substrate; and providing a second quantity of hydrogen chloride into the enclosure which serves to initially etch, and hence clean, the outer surface of the substrate prior to the formation of gallium arsenide thereon, and simultaneously tends to inhibit the formation of silicon contaminants on the substrate, the second quantity and the first quantity having a preselected ratio such that the growth rate of the

Abstract: In a charge coupled device provided with a two-phase overlapping gate structure, charge flow directionality is built into the structure by forming an asymmetrical potential well beneath each gate electrode with a single offset mask. High packing density is achieved in an array of staggered bits and with each bit being designed to have a geometry of minimum size.

Abstract: A microwave ferrite circulator includes a housing having three waveguide parts and a dual turnstile ferrite rotator. The ferrite rotator rotates an input signal through 120.degree. and consists of a dual arrangement of a dielectric transformer, a ferrite element disposed in a dielectric tube-shaped housing along with a conductive spacer. Accordingly the rotator when assembled is of a unitary construction and is held between two conductive transformers secured to the housing.

Abstract: Polyaminobismaleimides having superior thermomechanical properties can be produced by reacting maleimide terminated polyaliphatic ethers and maleimide terminated aromatic compounds with an aromatic diamine. These bismaleimide polymers display high recoverable elongation together with good tensile adhesive and electrical properties and thermal and fuel stability.

Abstract: A caging device for releasibly caging or clutching two relatively rotatable members to one another, such as a rotatable shaft to a fixed support or two independently rotatable shafts to one another, by axial movement of a clutch or caging member having a conically tapered clutch surface to and from a position of simultaneous engagement of its clutch surface with coaxial conically tapered clutch surfaces on the relatively rotatable members. The caging member can be electromechanically, hydraulically, pneumatically, or thermally actuated.

Abstract: A stunt kite comprising a first horizontal spar member, a second vertical spline member, third and fourth diagonal spar members, the members being formed into a fixed frame, a covering disposed on the frame and having a lateral dimension which is greater than its dimension corresponding to its longitudinal axis and being symmetrical in shape about the longitudinal axis, .[.a bow string forming the first member into a bowed shape such that the covering is bowed into a generally convex configuration,.].