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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 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Programmable, automated transistor test system

A programmable, automated transistor test system was built to supply experimental data on new and advanced power semiconductors. The data will be used for analytical models and by engineers in designing space and aircraft electric power systems. A pulsed power technique was used at low duty cycles in a nondestructive test to examine the dynamic switching characteristic curves of power transistors in the 500 to 1000 V, 10 to 100 A range. Data collection, manipulation, storage, and output are operator interactive but are guided and controlled by the system software.

Truong, L. V.↗
NASA NTRS1984

Programmable Real-Time Acousto-Optic/CCD SAR processor

The theory of operation of the Real-Time Acousto-Optic SAR Processor is reviewed and recent experimental results are presented. The results include a demonstration of the real-time imaging capability of the processor with simulated radar signals. An advanced version of this processor is then described in which a programmable reference function is entered via a second acousto-optic device to eliminate the need for a 2-D SLM. In this implementation the reference function is updated by electronic means to give the processor the flexibility to adapt rapidly to changes in the parameters of the radar/target geometry.

Haney, M.↗
NASA NTRS1986

A programmable transformer coupled converter for high-power space applications

A programmable transformer coupled converter (PTCC) is being developed by NASA/Marshall Space Flight Center for application in future large space power systems. The PTCC uses an internal microprocessor to control the output characteristics of its three Cuk integrated magnetics type power stages which have a combined capability of 5.4 kW (30 V at 180 A). Details of design trade-offs and test results are presented.

Kapustka, R. E.↗
NASA NTRS1986

RELBET 4.0 programmer's manual

The RELBET 4.0 System as implemented on the Hewlett Packard model 9000 computer system is described. The manual is directed toward programmers and system maintenance personnel. It is intended to serve both as a reference and as a introductory guide to the software. The body of the manual provides an overview of major features and indicates where to look for further information. Full details are left to Appendices.

Huysman, B. P.↗
NASA NTRS1987

Programmable electronic synthesized capacitance

A predetermined and variable synthesized capacitance which may be incorporated into the resonant portion of an electronic oscillator for the purpose of tuning the oscillator comprises a programmable operational amplifier circuit. The operational amplifier circuit has its output connected to its inverting input, in a follower configuration, by a network which is low impedance at the operational frequency of the circuit. The output of the operational amplifier is also connected to the noninverting input by a capacitor. The noninverting input appears as a synthesized capacitance which may be varied with a variation in gain-bandwidth product of the operational amplifier circuit. The gain-bandwidth product may, in turn, be varied with a variation in input set current with a digital to analog converter whose output is varied with a command word. The output impedance of the circuit may also be varied by the output set current. This circuit may provide very small ranges in oscillator frequency with relatively large control voltages unaffected by noise.

Kleinberg, Leonard L.↗
NASA NTRS1988

Programmable Grit-Blasting System

In programmable grit-blasting system undergoing design, controller moves blasting head to precise positions to shape or remove welding defects from parts. Controller holds head in position for preset dwell time and moves head to new position along predetermined path. Position of articulated head established by pair of servomotors according to programmed signals from controller. Head similar to video borescope. Used to remove welding defects in blind holes. Suited for repetitive production operations in grit-blast box.

Burley, Richard K.↗
NASA NTRS1988

Concept of a programmable maintenance processor applicable to multiprocessing systems

A programmable maintenance processor concept applicable to multiprocessing systems has been developed at the NASA Ames Research Center's Dryden Flight Research Facility. This stand-alone-processor is intended to provide support for system and application software testing as well as hardware diagnostics. An initial machanization has been incorporated into the extended aircraft interrogation and display system (XAIDS) which is multiprocessing general-purpose ground support equipment. The XAIDS maintenance processor has independent terminal and printer interfaces and a dedicated magnetic bubble memory that stores system test sequences entered from the terminal. This report describes the hardware and software embodied in this processor and shows a typical application in the check-out of a new XAIDS.

Glover, Richard D.↗
NASA NTRS1986

Comparison of programmable legend keyboard and dedicated keyboard for control of the flight management computer

A study is described which compares two types of input devices used to operate a flight management computer: a programmable legend (multifunction) keyboard and a conventional (dedicated) keyboard. Pilot performance measures, subjective responses, and a timeline analysis were used in evaluating the two keyboard concepts. A discussion of the factors to be considered in the implementation of a multifunction keyboard is included.

Crane, Jean M.↗
NASA NTRS1987

Development and implementation of a programmable telemetry processor

A programmable telemetry processor was designed for the NASA Goddard Space Flight Center in support of the Systems Utilization Enhancement (SUE) upgrade of the NASA tracking stations at Merritt Island, FL, and Bermuda. The processor is an integrated hardware and software system that performs the front-end telemetry synchronization and decommutation functions and provides for application-specific data processing. This paper presents the design, architecture, and features of the microprocessor controlled unit.

Flagg, Howard S.↗
NASA NTRS1989

Programmable rate modem utilizing digital signal processing techniques

The engineering development study to follow was written to address the need for a Programmable Rate Digital Satellite Modem capable of supporting both burst and continuous transmission modes with either binary phase shift keying (BPSK) or quadrature phase shift keying (QPSK) modulation. The preferred implementation technique is an all digital one which utilizes as much digital signal processing (DSP) as possible. Here design tradeoffs in each portion of the modulator and demodulator subsystem are outlined, and viable circuit approaches which are easily repeatable, have low implementation losses and have low production costs are identified. The research involved for this study was divided into nine technical papers, each addressing a significant region of concern in a variable rate modem design. Trivial portions and basic support logic designs surrounding the nine major modem blocks were omitted. In brief, the nine topic areas were: (1) Transmit Data Filtering; (2) Transmit Clock Generation; (3) Carrier Synthesizer; (4) Receive AGC; (5) Receive Data Filtering; (6) RF Oscillator Phase Noise; (7) Receive Carrier Selectivity; (8) Carrier Recovery; and (9) Timing Recovery.

Bunya, George K.↗
NASA NTRS1988

A programmable video image remapper

NASA's Johnson Space Center (JSC) has created the specifications for a new kind of image processing machine, a video-rate coordinate remapper. Previous image-processing machines for machine vision typically have done point operations without changing the geometry of the image. The JSC Programmable Remapper offers complete flexibility in changing the coordinates of an input image at video rates. Presented here are the main capabilities and some of the applications of such a device.

Fisher, Timothy E.↗
NASA NTRS1988

Guidelines for the use of programmable display pushbuttons on the Space Station's telerobot control panel

Simulations of a Remote Manipulator System task on microcomputer prototypes were performed to establish guidelines for using programmable display pushbuttons (PDP) on a telerobot control panel. Simulations of control panels with and without PDP were conducted. It is shown that there is a statistically significant increase in the number of commands issued in the non-PDP control panel. Guidelines for using PDP panels are listed.

Stuart, Mark A.↗
NASA NTRS1989

A programmable CCD driver circuit for multiphase CCD operation

A programmable CCD (charge-coupled device) driver circuit was designed to drive CCDs in multiphased modes. The purpose of the drive electronics is to operate developmental CCD imaging arrays for NASA's tiltable moderate resolution imaging spectrometer (MODIS-T). Five objectives for the driver were considered during its design: (1) the circuit drives CCD electrode voltages between 0 V and +30 V to produce reasonable potential wells, (2) the driving sequence is started with one input signal, (3) the driving sequence is started with one input signal, (4) the circuit allows programming of frame sequences required by arrays of any size, (5) it produces interfacing signals for the CCD and the DTF (detector test facility). Simulation of the driver verified its function with the master clock running up to 10 MHz. This suggests a maximum rate of 400,000 pixels/s. Timing and packaging parameters were verified. The design uses 54 TTL (transistor-transistor logic) chips. Two versions of hardware were fabricated: wirewrap and printed circuit board. Both were verified functionally with a logic analyzer.

Ewin, Audrey J.↗
NASA NTRS1990

Programmable Direct-Memory-Access Controller

Proposed programmable direct-memory-access controller (DMAC) operates with computer systems of 32000 series, which have 32-bit data buses and use addresses of 24 (or potentially 32) bits. Controller functions with or without help of central processing unit (CPU) and starts itself. Includes such advanced features as ability to compare two blocks of memory for equality and to search block of memory for specific value. Made as single very-large-scale integrated-circuit chip.

Hendry, David F.↗
NASA NTRS1990

Programmable Cadence Timer

Electronic metronome paces users through wide range of exercise routines. Conceptual programmable cadence timer provides rhythmic aural and visual cues. Timer automatically changes cadence according to program entered by the user. It also functions as clock, stopwatch, or alarm. Modular pacer operated as single unit or as two units. With audiovisual module moved away from base module, user concentrates on exercise cues without distraction from information appearing on the liquid-crystal display. Variety of uses in rehabilitative medicine, experimental medicine, sports, and gymnastics. Used in intermittent positive-pressure breathing treatment, in which patient must rhythmically inhale and retain medication delivered under positive pressure; and in incentive spirometer treatment, in which patient must inhale maximally at regular intervals.

Hall, William A.↗
NASA NTRS1990

Programmable Multizone Furnace

Moving thermal gradients created without mechanical motion. Furnace having multiple, individually programmable heating zones developed for use in experiments on directional solidification. Holds rod specimen and generates thermal gradients moving along specimen. Elimination of translation mechanism makes furnace more compact and reduces vibrations, which disturb experiment. Availability of different temperature profiles through programming makes it versatile tool for research at low thermal gradients traveling at moderate speeds.

Ting, Edmund Y.↗
NASA NTRS1990

Starting Circuit For Erasable Programmable Logic Device

Voltage regulator bypassed to supply starting current. Starting or "pullup" circuit supplies large inrush of current required by erasable programmable logic device (EPLD) while being turned on. Operates only during such intervals of high demand for current and has little effect any other time. Performs needed bypass, acting as current-dependent shunt connecting battery or other source of power more nearly directly to EPLD. Input capacitor of regulator removed when starting circuit installed, reducing probability of damage to transistor in event of short circuit in or across load.

Cole, Steven W.↗
NASA NTRS1990

PROTEUS two-dimensional Navier-Stokes computer code, version 1.0. Volume 3: Programmer's reference

A new computer code was developed to solve the 2-D or axisymmetric, Reynolds-averaged, unsteady compressible Navier-Stokes equations in strong conservation law form. The thin-layer or Euler equations may also be solved. Turbulence is modeled using an algebraic eddy viscosity model. The objective was to develop a code for aerospace applications that is easy to use and easy to modify. Code readability, modularity, and documentation were emphasized. The equations are written in nonorthogonal body-fitted coordinates, and solved by marching in time using a fully-coupled alternating-direction-implicit procedure with generalized first- or second-order time differencing. All terms are linearized using second-order Taylor series. The boundary conditions are treated implicitly, and may be steady, unsteady, or spatially periodic. Simple Cartesian or polar grids may be generated internally by the program. More complex geometries require an externally generated computational coordinate system. The documentation is divided into three volumes. Volume 3 is the Programmer's Reference, and describes the program structure, the FORTRAN variables stored in common blocks, and the details of each subprogram.

Towne, Charles E.↗