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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,693 records · Page 94

Float zone space processing rationale

The role of float zone silicon in integrated circuits is surveyed. The problem of oxygen thermal donors and their inhomogeneous distribution is predicted to be a critical issue.

Jastrzebski, L.↗

Multijunction high voltage concentrator solar cells

The standard integrated circuit technology has been developed to design and fabricate new innovative planar multi-junction solar cell chips for concentrated sunlight applications. This 1 cm x 1 cm cell consisted of several voltage generating regions called unit cells which were internally connected in series within a single chip resulting in high open circuit voltages. Typical open-circuit voltages of 3.6 V and short-circuit currents of 90 ma were obtained at 80 AM1 suns. A dramatic increase in both short circuit current and open circuit voltage with increased light levels was observed.

Valco, G. J.↗

Telemetry methods for monitoring physiological parameters

The use of telemetry to monitor various physiological functions is discussed. The advantages of the technique and the parameters that it can monitor are assessed, and the main telemetry systems, including pressure telemetry, flow telemetry, and multichannel telemetry, are detailed. Human applications of implanted flow transducers, total implant versus backpack telemetry, the use of power sources and integrated circuits in telemetry, and the future prospects of the technique in hypertension treatment and research are discussed.

Fryer, T. B.↗

Coding for Single-Line Transmission

Digital transmission code combines data and clock signals into single waveform. MADCODE needs four standard integrated circuits in generator and converter plus five small discrete components. MADCODE allows simple coding and decoding for transmission of digital signals over single line.

Madison, L. G.↗

Improving Trace-Ion Sensitivity

Background noise reduced by some special precautions. Blanket of argon flows over solution so no chance for contamination from air to creep in. Conventional pump replaced with one made of polytetrafluoroethlylene component and all metal couplings eliminated from flow lines. Used to improve quality control in integrated circuit fabrication, lens fabrication, and vacuum-tube assembly.

Buggle, R. N.↗

Radiation-Hardness Data For Semiconductor Devices

Document presents data on and analysis of radiation hardness of various semiconductor devices. Data specifies total-dose radiation tolerance of devices. Volume 1 of report covers diodes, bipolar transistors, field effect transistors, silicon controlled rectifiers and optical devices. Volume 2 covers integrated circuits. Volume 3 provides detailed analysis of data in volumes 1 and 2.

Price, W. E.↗

Self-Checking Memory Interface

Memory-interface integrated circuit not only detects errors in data from other circuits but also detects errors within itself. Memory-interface chip encodes 16-bit words with Hamming code for single-error correction or double-error detection. Chip used in fault-tolerant computers under development by NASA.

Sievers, M. W.↗

Simplification of power electronics for ion thruster neutralizers

A need exists for less complex and lower cost ion thruster systems. Design approaches and the demonstration of neutralizer power electronics for relaxed neutralizer keeper, tip heater, and vaporizer requirements are discussed. The neutralizer circuitry is operated from a 200 to 400 V bus and demonstrates an order of magnitude reduction in parts count. Furthermore, a new technique is described for regulating tip heater power and automatically switching over to provide keeper power with only four additional components. A new design to control the flow rate of the neutralizer with one integrated circuit is also presented.

Gruber, R. P.↗

Synchronized voltage contrast display analysis system

An apparatus and method for comparing internal voltage potentials of first and second operating electronic components such as large scale integrated circuits (LSI's) in which voltage differentials are visually identified via an appropriate display means are described. More particularly, in a first embodiment of the invention a first and second scanning electron microscope (SEM) are configured to scan a first and second operating electronic component respectively. The scan pattern of the second SEM is synchronized to that of the first SEM so that both simultaneously scan corresponding portions of the two operating electronic components. Video signals from each SEM corresponding to secondary electron signals generated as a result of a primary electron beam intersecting each operating electronic component in accordance with a predetermined scan pattern are provided to a video mixer and color encoder.

Johnston, M. F.↗

Application of MMIC modules in future multiple beam satellite antenna systems

Multiple beam antenna systems for advanced communication satellites operating in the 30/20 GHz frequency bands (30 GHz uplink, 20 GHz downlink) were developed. Up to twenty 0.3 deg HPBW fixed spot beams and six 0.3 deg HPBW scanning spot beams will be required. Array-fed dual reflector antenna systems in which monolithic microwave integrated circuit (MMIC) phase shift and amplifier modules are used with each radiating element of the feed array for beam pointing and power gain were developed. The feasibility of distributed power amplification and beam pointing with MMIC modules in the elements of an array and to develop a data base for future development were demonstrated. The technical discussion centers around the potential advantages of ""monolithic'' antennas for specific applications as compared to systems using high powered TWT's. These include: reduced losses in the beam forming network; advantage of space combining and graceful degradation; dynamic control of beam pointing and illumination contour; and possibilities for cost and weight reduction.

Smetana, J.↗

Phased array-fed antenna configuration study: Technology assessment

Spacecraft array fed reflector antenna systems were assessed for particular application to a multiple fixed spot beam/multiple scanning spot beam system. Reflector optics systems are reviewed in addition to an investigation of the feasibility of the use of monolithic microwave integrated circuit power amplifiers and phase shifters in each element of the array feed.

Croswell, W. F.↗

Conceptual design of a data reduction system

A telemetry data processing system was defined of the Data Reduction. Data reduction activities in support of the developmental flights of the Space Shuttle were used as references against which requirements are assessed in general terms. A conceptual system design believed to offer significant throughput for the anticipated types of data reduction activities is presented. The design identifies the use of a large, intermediate data store as a key element in a complex of high speed, single purpose processors, each of which performs predesignated, repetitive operations on either raw or partially processed data. The recommended approach to implement the design concept is to adopt an established interface standard and rely heavily on mature or promising technologies which are considered main stream of the integrated circuit industry. The design system concept, is believed to be implementable without reliance on exotic devices and/or operational procedures. Numerical methods were employed to examine the feasibility of digital discrimination of FDM composite signals, and of eliminating line frequency noises in data measurements.

Source record↗

Scanning beam antenna conceptual design for 20/30 GHz satellite systems

The configuration described is one of four antenna system configurations developed using a variety of monolithic microwave integrated circuit module arrangements and optical systems. A parametric analysis is expected to produce a data base for the selection of design points for a variety of applications. Soon to be accomplished is the design concept of the active (lens) array, which will take into consideration such factors as, coupling effects, the space-fed power divider network design, input bias and control layout, investigation of thermal distribution, and analysis of module failure (graceful degradation).

Smetana, J.↗

Spacecraft in switch matrix for wide band service applicatons in 30/20 GHz communications satellite systems

Bandwidth, switching speed, off-state isolation, and reliability over a ten-year mission were factors in determining the optimum available technology for satellite communications switching in 1982. A proof of concept model for a 20 x 20 coupled crossbar switch matrix designed with FET devices for microwave switching and with high speed CMOS LIS for switch crosspoint addressing was fabricated and tested. Results show the design is feasible for application in a multichannel SS-TDMA communications system. Expandibility can readily be achieved with this design. A conceptual design study for a 100 x 100 switch matrix utilizing a coupled crossbar architecture implemented with a monolithic microwave integrated circuits revealed technology needs for high capacity switch matrices.

Cory, B. J.↗

Test chips for custom ICs - Six kinds of test structures

Microelectronic test chips contain a number of test structures that are used for a variety of purposes in fabricating integrated circuits. For convenience, their use is divided into six groups: layout-rule evaluating, process-parameter extraction, device-parameter extraction, circuit-parameter extraction, initial-fabrication failure analysis, and reliability failure analysis. A given test structure can be used to gather information in a number of these groups. Examples are given here of the kinds of parameters that can be obtained in each of these groups. A table is included summarizing various device failures common to bulk CMOS and indicating failure mechanisms appearing after wafer fabrication and after stress.

Buehler, M. G.↗

Semiconductor Laser Phased Array

Oscillations synchronized and modulated individually for beam steering. Phased array of GaAs infrared lasers put out powerful electronically-steerable coherent beam. Fabricated as integrated circuit on GaAs chip, new device particularly suited to optical communications, optical data processing and optical detection and ranging systems.

Katz, J.↗

Fast Dual Analog-to-Digital Converter

Unit delivers blocks of quadrature data to computer memory. Contains 105 integrated circuit packages in 19 by 3 1/2 inch (48.26 by 8.39 cm) rack mounted drawer with internal force air blower. Intended for synchronous sampling of quadrature pairs of data, samples with minimal skew (about 10 nanoseconds) using video-type high-speed sampling technology. Unit equipped for computer controlled self-testing. Originally developed for planetary radar data-acquisition system.

Wallis, D. E.↗

Wire-Identification Instrument

Instrument automatically tests each wire in multiwire cable and identifies specified wire to be segregated or labeled and locates wire connected to specified connector pin. Instrument made with readily available CMOS integrated circuits. More efficient and reliable than conventional continuity testers and less expensive than computer controlled units.

Lonborg, J. O.↗