Abstract: A fast Fourier transform circuit formed on a single chip, including a fast multiplier-accumulator circuit which, in the preferred embodiment, employs a modified form of Booth's algorithm, an adder circuit, a read-only memory for storing FFT twiddle factors, and a random access memory for holding a set of input complex quantities and for receiving intermediate and final results in an in-place FFT operation. In the preferred embodiment, the FFT twiddle factors are stored in Booth's code for greater speed of operation. Control and timing circuitry on the same chip generates control signals and address codes in order to perform a sequence of butterfly computations by repeated use of the multiplier-accumulator and adder circuits, to generate FFT coefficients in the random access memory.

Abstract: A radio-frequency switch of planar construction for connecting N input signals to M output signals in a broadcast switch mode or a matrix switch mode. The switch includes a single substrate or circuit board (49) and M output switches (50) disposed in a row on one face of the board, each output switch having N input ports. In the broadcast mode, there are N rows of distributed power dividers (such as 60, 62, 64 and 66), each row providing M outputs from a single input port, the outputs being connected by conductors (such as 90) to the output switches (50). The conductors effecting these cross-connections are formed for the most part on the reverse face of the circuit board, to avoid intersection between the cross-connections and the distributed power dividers. In the matrix mode, the power dividers are replaced by switches (110).

Abstract: A monolithic storage array (10) having multiple write ports (12, 14) and multiple read ports (16, 18), which may be used simultaneously in any combination. Each cell of the illustrative array has two storage flip-flops (Q1/Q4 and Q5/Q8), one for connection to each read port, and has a switching network (Q9-Q16) for connecting write-port row and column selection signals to set or reset both flip-flops as desired. Row selection for reading is effected by raising a power supply voltage coupled to the flip-flops, to increase noise immunity, and the device has only four isolated collectors, for high device density in monolithic form.

Abstract: A monolithic convolver circuit making extensive use of "pipelined" architecture to ensure high speed by concurrency of processing, and having a repetitive stage to facilitate chip layout and manufacture. The circuit includes a multiplier and an adder in each stage. The adders produce a sequence of summation terms concurrently and include shift registers to move and accumulate the results of convolution. The adders produce only partial sums at each stage, to increase processing speed. Full computation of carries is deferred until the very end, and performed in a separate conditional sum adder.

Abstract: A spacecraft or transfer vehicle for transportation of a payload from a space shuttle parking orbit to a higher operation orbit, wherein the transfer vehicle utilizes housekeeping subsystems integrated into the payload, to avoid unnecessary duplication of these subsystems, for such functions as power supply, guidance, control, and communications. The transfer vehicle disclosed includes a propulsion system with at least one low-thrust bipropellant liquid rocket engine, to provide a "soft" or low-acceleration ascent, and employs two tanking stages, each having four propellant tanks, arranged symmetrically in a circular configuration. The first stage of four tanks is jettisoned during ascent, and the second stage, including the remaining four tanks, the rocket engine, and related supporting structure, is separated from the payload when the operational orbit is reached.

Abstract: Apparatus, and a related method, for fast carrier acquisition in a modem. The apparatus includes circuitry to speed carrier acquisition by the determination of which of two alternate phasors is being received during a baud synchronization period of a signal preamble before data transmission. Another aspect of the invention involves the use of a complex matched filter for the determination of the start of an equalizer training sequence in the signal preamble. The output of the matched filter exhibits a deep null at the start of the training sequence, since the beginning of the sequence bears an inverse relationship to the end of the preceeding baud synchronization period.

Abstract: Method and apparatus for providing a sequence of digitized samples to a modem in substantial synchronism with the incoming signal baud rate, but without using a variable sampling frequency. An incoming signal is sampled at a fixed rate, stored temporarily in a buffer memory, and then interpolated using a digital interpolation filter to provide a sequence of interpolated samples that are equivalent to those that would have been obtained if a variable-frequency sampling rate had been used. Any relative delay between the samples supplied to the modem and the baud rate is sensed and accumulated in an up/down counter. Then the accumulated delay stored in the counter is used to control the selection of coefficients for the interpolation filter.

Abstract: A process and related product in which ohmic contacts are formed in semiconductor devices employing compound substrates such as gallium arsenide. In the disclosed embodiment, a germanium layer (18) is deposited in those areas (14) in which ohmic contact is required and is subsequently diffused into a layer 20 of the substrate during a conventional annealing step required to relieve damage caused to the substrate during a prior conventional ion implantation step. As a result of the diffusion of the germanium, good ohmic contact can be made by deposition of a conductive metal 26, such as gold. Thus, a common metalization step can be employed to form both the ohmic contact regions and rectifying contact regions used as gates in field effect transistors.

Abstract: A method for removing ash, sulfur and inertinite from crushed coal includes float/sink treatment in aqueous solutions of monosaccharides, disaccharides, hydrogenated monosaccharides, hydrogenated disaccharides and mixtures thereof. Such solutions also improve the performance of such heavy media physical cleaning equipment as cyclones, heavy media baths, tables, spirals, hydroclones, flotation cells, jigs and solid-bowl centrifuges.

Abstract: a tri-mode coupler (80) for developing from a received signal including three waveguide propagation modes the three tracking signals (i.e. sum signal, elevation signal, and azimuth signal) used in a high-frequency monopulse tracking system and for transmitting a signal at a different frequency, the coupler comprises broadband means such as a two-arm turnstile junction (84) coupling a first circular waveguide section (82) to an E-plane folded hybrid junction (90) for separating out one waveguide mode of the received signal and receiving the signal to be transmitted, and a second circular waveguide section (86) of smaller diameter than the first waveguide section and coupling the latter section to an additional E-plane folded hybrid junction (88) for separating out the two additional waveguide modes of the received signal.

Abstract: A controlled scintillation rate decoy having microwave reflectors for reflecting incident radar energy in a manner to provide the decoy with a selected radar cross-section, and variable electrical impedance control means connected in electrical circuit with the reflectors for controlling the scintillation magnitude or scintillation rate of the decoy.

Abstract: The present invention resides in a dual fueled burner gun providing reduced production of oxides of nitrogen. The gun operates in a gaseous fueled mode when it is charged with a gaseous fuel or in a liquid fueled mode when it is charged with a liquid fuel. The gun may also operate in a gaseous/liquid fueled mode in which it is charged with both the gaseous and liquid fuels.

Abstract: A connector for interconnecting two conductors comprises a plug component for mating engagement with a receptacle component. The plug component has a conductor means therein and a first elastomeric sealing membrance covering the mating end thereof to seal the same, the sealing membrane having a slit therein. The receptacle component includes conductor receiving means therein and a second elastomeric sealing membrane covering the mating end thereof to seal the same. The second sealing membrane also has a slit therein, the slits in each of the sealing membranes being positioned to register upon mating engagement of the plug and receptacle components. The connector further includes displacement means operable upon the mating engagement of the plug and receptacle components to stretch the first and second sealing membranes in a direction transverse to the slits to open the slits to permit the passage of the conductor means therethrough during engagement and disengagement of the components.

Abstract: A successive approximation analog-to-digital converter controllable by signals to start and interrupt conversion asynchronously with respect to clock signals used to regulate operation of the converter. Separate control signal processing circuits register the occurrence of start-convert and conversion-interrupt signals supplied by a user of the converter, and generate corresponding control signals synchronized with the clock signals. Asynchronous operation of the converter allows it to function in a short-cycling mode, wherein the number of bits of resolution in the conversion process is automatically reduced as little as possible to complete each conversion in the time allotted by the user. A continuous-conversion signal is also provided, to permit operation on a continuous basis, without providing periodic start-convert signals.

Abstract: Oxidized carbonaceous materials suitable for reinforcing such diene rubbers as styrene-butadiene rubber and natural rubber include carbon, oxidized iron dispersed in, intimately associated with and at least partially bonded to the carbon, and hydrogen.

Abstract: An improved sequential threshold detection circuit for use in the receiver of a spread-spectrum communication system is disclosed wherein the improvement resides in the employment of a feedback circuit for maintaining a pre-selected constant median dismissal time. In the preferred embodiment the feedback circuit comprises a flip-flop (70), a very long time constant integrator (72), and a one-shot (74) connected between a comparator (64) and a summing amplifier (60) for varying a threshold bias voltage applied to the summing amplifier. In an alternative embodiment, the feedback circuit serves to selectively vary the gain of a variable gain amplifier (110) in such a manner to vary the individual trial and error dismissal times to provide a substantially constant median dismissal time over the entire detection process.

Abstract: A deployable panel structure for spacecraft solar cell arrays and other collapsible panel structures. The panel structure consists of a number of panel sections mounted edge to edge along parallel hinge lines by hinges which allow the panels to be collapsed accordian fashion toward a support. The panels are attached to and deployed by an extendable boom which is extended from and retractable to the support. In the deployed configuration, the panels are extended to form a planar surface in which the boom is essentially coplanar. The panel sections are formed from a plurality of layers of thin film insulative substrate which is stiffened with ribs formed into the substrate during the manufacturing process. The hinges are formed of the same material as the substrate and bonded to the edges of the panel. The bonding is accomplished while the panels are in the folded, face-to-face position such that maximum stored energy and out-of-plane stiffness is available in the deployed configuration.

Abstract: An active semiconductor device, such as a Gunn effect device, capable of operation at extremely high frequencies, fabricated in situ on a substrate that also serves as a dielectric waveguide to propagate energy from the device. In the embodiment disclosed, a Gunn effect diode is formed on a substrate of gallium arsenide (GaAs), together with a cavity region and a metalized heat sink layer permitting operation at relatively high power levels. A bias current is applied through a conductive strip and then through the cavity region to the diode, and a quarter-wave choke is provided in the conductive strip to prevent transmission of radio-frequency energy back along the strip.

Abstract: In-situ retorting methods include forming an in-situ mass of rubblized, hydrocarbon-containing minerals covering at least part of that mass with a nonflammable liquid such as water, uncovering part of the mass and retorting to produce hydrocarbon values from that part, and then progressively or sequentially uncovering other parts of the mass and retorting hydrocarbons from those parts. Methods for forming highly permeable rubblized masses include forming a retorting zone in a kerogen-bearing formation wherein two walls of the retorting zone form a low angle to one another, and cleaving oil shale from the upper wall beginning near the intersection of the two walls and proceeding upwardly.

Abstract: Sulfided carbonaceous materials suitable for reinforcing such diene rubbers as styrene-butadiene rubber and natural rubber include carbon, sulfided iron dispersed in, intimately associated with and at least partially bonded to the carbon, and hydrogen.