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At least 109 records · Page 6

Stochastic analysis of multiple-passband spectral classifications systems affected by observation errors

The classification of targets viewed by a pushbroom type multiple band spectral scanner by algorithms suitable for implementation in high speed online digital circuits is considered. A class of algorithms suitable for use with a pipelined classifier is investigated through simulations based on observed data from agricultural targets. It is shown that time distribution of target types is an important determining factor in classification efficiency.

Tsokos, C. P.↗

Standard Transistor Arrays

Standard Transistor Array (STAR) design system is semicustom approach to generating random-logic integrated MOS digital circuits. Primary program in STAR system is CAPSTAR, STAR Cell Arrangement Program. CAPSTAR is augmented by automatic routining program, Display program and library of logic cells.

Cox, G. W.↗

Rounding Technique for High-Speed Digital Signal Processing

Arithmetic technique facilitates high-speed rounding of 2's complement binary data. Conventional rounding of 2's complement numbers presents problems in high-speed digital circuits. Proposed technique consists of truncating K + 1 bits then attaching bit in least significant position. Mean output error is zero, eliminating introducing voltage offset at input.

Wechsler, E. R.↗

Solid-State Crossbar Switch

Combines analog and digital circuits for multiline/multiport switching. Bidirectional solid-state crossbar switch provides interfacing and switching for 16 X24 coordinate ports for 16 parallel signal lines. Intended for rapid manual-controlled or computer controlled reconfiguration of distributed computing systems.

Anderson, T. O.↗

Digital Sequence Controller

Length and timing of pulse sequences user controlled. Digital circuit generates several pulse streams to control loads that must be synchronized allowing duration and phasing of each stream to be varied independently. Application of circuit to control pump for biomedical applications.

Lonborg, J. O.↗

VLBI System (BLK I) If-video down Conversion Design

The prototype intermediate frequency video down converter of the Deep Space Network (BLK 1) Very Long Base Interferometry system, a hybrid of analog and digital circuits, was completed and tested. The initial results met all design specifications, establishing a milestone in new design technology for such devices. This device has uses in other similar applications and can form the basis for expanded design and applications.

Ham, N. C.↗

Intermediate-Frequency-to-Video-Band Converter

Analog and digital circuits combined to frequency-convert from intermediate frequencies directly to video-band frequencies to meet stringent requirements. IF-to-video-band converter operates on principle of signal-band cancellation in phase-quadrature circuits. Downconverts intermediate frequencies directly to video-band frequencies to near-zero frequency with good image-band rejection and low phase variation within passband.

Ham, N. C.↗

Ulysses: A functional description and simulation software system

Current design tools for digital circuits and systems are not well-integrated among the behavioral, gate, and transistor levels of design. Ulysses is a prototype software system that consists of a description language, a description compiler, and a simulator that make no distinction among these levels. The language is uniform over the entire range of logical descriptions, the description is hierarchical with no fundamental restrictions on depth or mixing of levels, and the simulator is fully integrated with the description. The structure of the language, compiler, and simulator are described in terms of their relationships to the abstractions of physical systems that are made in order to create logical descriptions and models of behavior.

Griswold, T. W.↗

Analog/Digital System for Germanium Thermometer

Electronic system containing analog and digital circuits makes high-precision, four-wire measurements of resistance of each germanium resistance thermometer (GRT) in array of devices, using alternating current (ac) of 1 micro-A. At end measurement interval, contents of negative register subtracted from positive one, resulting in very-narrow-band synchronous demodulation of carrier wave and suppression of out-of-band noise. Microprocessor free to perform other duties after measurement complete. Useful in noisy terrestrial environments encountered in factories.

Woodhouse, Christopher↗

Generating Weighted Test Patterns for VLSI Chips

Improved built-in self-testing circuitry for very-large-scale integrated (VLSI) digital circuits based on version of weighted-test-pattern-generation concept, in which ones and zeros in pseudorandom test patterns occur with probabilities weighted to enhance detection of certain kinds of faults. Requires fewer test patterns and less computation time and occupies less area on circuit chips. Easy to relate switching activity in outputs with fault-detection activity by use of probabilistic fault-detection techniques.

Siavoshi, Fardad↗

Improved ranging systems

Spacecraft range measurements have provided the most accurate tests, to date, of some relativistic gravitational parameters, even though the measurements were made with ranging systems having error budgets of about 10 meters. Technology is now available to allow an improvement of two orders of magnitude in the accuracy of spacecraft ranging. The largest gains in accuracy result from the replacement of unstable analog components with high speed digital circuits having precisely known delays and phase shifts.

Young, Larry E.↗

Laser-Power Controller

New controller used in place of commercial controller. Provides precision and simplicity of digital settings, and all timing determined by digital circuits. Built-in circuit counts number of pulses in, and thereby provides control over, duration of each burst; duration set at precise value within wide range or each pulse set precisely. Controller easily adaptable to computer control: single switch used to select either manual or computer control. Another single-switch selection feature provides choice between counting of pulses in, and manual timing of, bursts.

Smith, William C.↗

Artificial intelligence and design: Opportunities, research problems and directions

The issues of industrial productivity and economic competitiveness are of major significance in the U.S. at present. By advancing the science of design, and by creating a broad computer-based methodology for automating the design of artifacts and of industrial processes, we can attain dramatic improvements in productivity. It is our thesis that developments in computer science, especially in Artificial Intelligence (AI) and in related areas of advanced computing, provide us with a unique opportunity to push beyond the present level of computer aided automation technology and to attain substantial advances in the understanding and mechanization of design processes. To attain these goals, we need to build on top of the present state of AI, and to accelerate research and development in areas that are especially relevant to design problems of realistic complexity. We propose an approach to the special challenges in this area, which combines 'core work' in AI with the development of systems for handling significant design tasks. We discuss the general nature of design problems, the scientific issues involved in studying them with the help of AI approaches, and the methodological/technical issues that one must face in developing AI systems for handling advanced design tasks. Looking at basic work in AI from the perspective of design automation, we identify a number of research problems that need special attention. These include finding solution methods for handling multiple interacting goals, formation problems, problem decompositions, and redesign problems; choosing representations for design problems with emphasis on the concept of a design record; and developing approaches for the acquisition and structuring of domain knowledge with emphasis on finding useful approximations to domain theories. Progress in handling these research problems will have major impact both on our understanding of design processes and their automation, and also on several fundamental questions that are of intrinsic concern to AI. We present examples of current AI work on specific design tasks, and discuss new directions of research, both as extensions of current work and in the context of new design tasks where domain knowledge is either intractable or incomplete. The domains discussed include Digital Circuit Design, Mechanical Design of Rotational Transmissions, Design of Computer Architectures, Marine Design, Aircraft Design, and Design of Chemical Processes and Materials. Work in these domains is significant on technical grounds, and it is also important for economic and policy reasons.

Amarel, Saul↗

Acceleration recorder and playback module

The present invention is directed to methods and apparatus relating to an accelerometer electrical signal recorder and playback module. The recorder module may be manufactured in lightweight configuration and includes analog memory components to store data. Signal conditioning circuitry is incorporated into the module so that signals may be connected directly from the accelerometer to the recorder module. A battery pack may be included for powering both the module and the accelerometer. Timing circuitry is included to control the time duration within which data is recorded or played back so as to avoid overloading the analog memory components. Multiple accelerometer signal recordings may be taken simultaneously without analog to digital circuits, multiplexing circuitry or software to compensate for the effects of multiplexing the signals.

Bozeman, Richard J., Jr.↗

DRS: Derivational Reasoning System

The high reliability requirements for airborne systems requires fault-tolerant architectures to address failures in the presence of physical faults, and the elimination of design flaws during the specification and validation phase of the design cycle. Although much progress has been made in developing methods to address physical faults, design flaws remain a serious problem. Formal methods provides a mathematical basis for removing design flaws from digital systems. DRS (Derivational Reasoning System) is a formal design tool based on advanced research in mathematical modeling and formal synthesis. The system implements a basic design algebra for synthesizing digital circuit descriptions from high level functional specifications. DRS incorporates an executable specification language, a set of correctness preserving transformations, verification interface, and a logic synthesis interface, making it a powerful tool for realizing hardware from abstract specifications. DRS integrates recent advances in transformational reasoning, automated theorem proving and high-level CAD synthesis systems in order to provide enhanced reliability in designs with reduced time and cost.

Bose, Bhaskar↗

High-Performance Computing for the Electromagnetic Modeling and Simulation of Interconnects

The electromagnetic modeling of packages and interconnects plays a very important role in the design of high-speed digital circuits, and is most efficiently performed by using computer-aided design algorithms. In recent years, packaging has become a critical area in the design of high-speed communication systems and fast computers, and the importance of the software support for their development has increased accordingly. Throughout this project, our efforts have focused on the development of modeling and simulation techniques and algorithms that permit the fast computation of the electrical parameters of interconnects and the efficient simulation of their electrical performance.

Schutt-Aine, Jose E.↗

Silicon Satellites: Picosats, Nanosats, and Microsats

Silicon, the most abundant solid element in the Earth's lithosphere, is a useful material for spacecraft construction. Silicon is stronger than stainless steel, has a thermal conductivity about half that of aluminum, is transparent to much of the infrared radiation spectrum, and can form a stable oxide. These unique properties enable silicon to become most of the mass of a satellite, it can simultaneously function as structure, heat transfer system, radiation shield, optics, and semiconductor substrate. Semiconductor batch-fabrication techniques can produce low-power digital circuits, low-power analog circuits, silicon-based radio frequency circuits, and micro-electromechanical systems (MEMS) such as thrusters and acceleration sensors on silicon substrates. By exploiting these fabrication techniques, it is possible to produce highly-integrated satellites for a number of applications. This paper analyzes the limitations of silicon satellites due to size. Picosatellites (approximately 1 gram mass), nanosatellites (about 1 kg mass), and highly capable microsatellites (about 10 kg mass) can perform various missions with lifetimes of a few days to greater than a decade.

Janson, Siegfried W.↗

Acceleration Recorder and Playback Module

The present invention is directed to methods and apparatus relating to an accelerometer electrical signal recorder and playback module. The recorder module may be manufactured in lightweight configuration and includes analog memory components to store data. Signal conditioning circuitry is incorporated into the module so that signals may be connected directly from the accelerometer to the recorder module. A battery pack may be included for powering both the module and the accelerometer. Timing circuitry is included to control the time duration within which data is recorded or played back so as to avoid overloading the analog memory components. Multiple accelerometer signal recordings may be taken simultaneously without analog to digital circuits, multiplexing circuitry or software to compensate for the effects of multiplexing the signals.

Bozeman, Richard J., Jr.↗