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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Digital filter realizations using a special-purpose stored-program computer.

A special-purpose computer is organized to realize a second-order digital filter in a choice of 11 programming forms. Instructions for the forms are stored in a fast-access READ-ONLY memory. Also, a hard-wired multiplier is employed in the Arithmetic Unit to decrease computation time. The multiplier is organized into uniform functional blocks that are suitable for large-scale integration (LSI). A computer-aided design (CAD) program may be used to select the best filter programming form for a given filter transfer function D(z). The CAD program also aids in the location of the binary point in the data registers of the computer.

White, R.↗
NASA NTRS1973

Alphanumeric character generator for oscilloscope

Compact portable alphanumeric display device can be used with any general-purpose externally-triggered oscilloscope without need for Z-axis modulation. Factors limiting size of display are: output line capacitance, read-only memory speed, and persistence of cathode-ray-tube.

Lockerson, D. C.↗
NASA NTRS1973

Microprogrammed digital filters for strapdown guidance application.

Discussion of an approach for implementing digital filters using microprogrammed control logic with read only memory (ROM) for strapdown guidance applications, and description of a second-order multiplexed system using multiprogrammed control instruction. The microprogramming technique for control using ROM is shown to enhance higher order digital filter realization. The high speed of digital circuits reduces propagation time and facilitates multiplexing. Programmed ROM's can be altered easily for different algorithms.

Kapadia, K.↗
NASA NTRS1974

A magnetic bubble domain flight recorder

A feasibility model of an all-electronic bubble memory system has been constructed. It uses a small 60k bit bubble recorder consisting of 6 chips of 10k bits each mounted in three separate packages operating as a FIFO at a 150 KHz bubble data rate. In addition to serving as a direct tape recorder replacement, the bubble recorder can be programmed for random access to each individual chip for ranom block access operation or for self-checking or by-passing any malfunctioning memory chip. Read and write operations can be performed asynchronously from very low frequency up to basic recording field frequency. A large 50M bit prototype is planned.

Chen, T. T.↗
NASA NTRS1977

Microprogramed telemetry processor

Minimum hardware, reliable processor responds rapidly to changing requirements simply by changes in contents of programmable read-only memory. General purpose controller can transfer data onto and off of data bus, perform logic and arithmetic manipulations, and store pertinent data in small internal random-access memory.

Gordon, L. H.↗
NASA NTRS1975

An interactive method for digitizing zone maps

A method is presented for digitizing maps that consist of zones, such as contour or climatic zone maps. A color-coded map is prepared by any convenient process. The map is then read into memory of an Image 100 computer by means of its table scanner, using colored filters. Zones are separated and stored in themes, using standard classification procedures. Thematic data are written on magnetic tape and these data, appropriately coded, are combined to make a digitized image on tape. Step-by-step procedures are given for digitization of crop moisture index maps with this procedure. In addition, a complete example of the digitization of a climatic zone map is given.

Giddings, L. E.↗
NASA NTRS1975

Multimission spacecraft Dataplexer

The data multiplexing unit described is a low-power small-size building-block-type central data system designed for use on such spacecraft as the International Ultraviolet Explorer or the International Sun-Earth Explorer. Preprogrammed read-only memories are used to generate the telemetry format tailored to particular mission requirements. Low weight and low power dissipation are achieved with the aid of PMOS technology. The use of subcommutators in groups to meet particular spacecraft requirements allows low data rate experiments to be time-multiplexed into a single main input channel, to improve data collection and processing operations. The block diagram of the Dataplexer is discussed.

Cosme, R.↗
NASA NTRS1977

Programmable data communications controller requirements

The design requirements for a Programmable Data Communications Controller (PDCC) that reduces the difficulties in attaching data terminal equipment to a computer are presented. The PDCC is an interface between the computer I/O channel and the bit serial communication lines. Each communication line is supported by a communication port that handles all line control functions and performs most terminal control functions. The port is fabricated on a printed circuit board that plugs into a card chassis, mating with a connector that is joined to all other card stations by a data bus. Ports are individually programmable; each includes a microprocessor, a programmable read-only memory for instruction storage, and a random access memory for data storage.

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NASA NTRS1979

CMOS-array design-automation techniques

Thirty four page report discusses design of 4,096-bit complementary metal oxide semiconductor (CMOS) read-only memory (ROM). CMOSROM is either mask or laser programable. Report is divided into six sections; section one describes background of ROM chips; section two presents design goals for chip; section three discusses chip implementation and chip statistics; conclusions and recommendations are given in sections four thru six.

Feller, A.↗
NASA NTRS1978

A cycle timer for testing electric vehicles

A cycle timer was developed to assist the driver of an electric vehicle in more accurately following and repeating SAE driving schedules. These schedules require operating an electric vehicle in a selected stop-and-go driving cycle and repeating this cycle pattern until the vehicle ceases to meet the requirements of the cycle. The heart of the system is a programmable read-only memory (PROM) that has the required test profiles permanently recorded on plug-in cards, one card for each different driving schedule. The PROM generates a direct current analog signal that drives a speedometer displayed on one scale of a dual movement meter. The second scale of the dual movement meter displays the actual speed of the vehicle as recorded by the fifth wheel. The vehicle operator controls vehicle speed to match the desired profile speed. The PROM controls the recycle start time as well as the buzzer activation. The cycle programmer is powered by the test vehicle's 12-volt accessory battery, through a 5-volt regulator and a 12-volt dc-to-dc converter.

Soltis, R. F.↗
NASA NTRS1979

A structure for digital notch filters

Narrow-band digital notch filters have their poles near the unit circle. As the sampling rate is increased, the poles move towards Z = +1. Implementing such filters requires long registers to overcome the sensitivity and roundoff errors. A filter structure based on digital incremental computers is proposed which has low sensitivity and round-off errors, and simple hardware implementation. The filter structure can be directly used on differentially pulse-code modulated signals. Hardware multipliers are not required as the poles approach z = +1, and excellent results can be obtained using multipliers with very short word lengths, or with small size read-only memories.

Abu-El-haija, A. I.↗
NASA NTRS1978

A cycle timer for testing electric vehicles

The paper presents a cycle timer which enables the accurate following and repetition of SAE driving schedules of stop and go cycles, for electric vehicles, by reducing the human factor. The system which consists of a programmable read-only memory (PROM) stores each of these cycles, which are detailed, on its own plug-in card. The actual vehicle speed, and the PROM indicated desired speed are displayed on a dual scale meter allowing the driver to match them. A speed change is preceded by a half second buzzer warning and a new cycle by a one second warning. The PROM controls the recycle start time as well as the buzzer activation. A 5 volt regulator providing logic power, and a 12 volt dc-dc converter providing analog and memory power are described.

Soltis, R. F.↗
NASA NTRS1980

Microprocessor-based detector for PSK commands

Command detector unit operates over wide range of data rates and signal levels in space environment. It consists of signal conditioning, read-only memory, random-access memory, and digital processor. Entire unit fits on single multilayer printed-wiring board.

Durden, J.↗
NASA NTRS1981

Fast calibration of gas flowmeters

Digital unit automates calibration sequence using calculator IC and programmable read-only memory to solve calibration equations. Infrared sensors start and stop calibration sequence. Instrument calibrates mass flowmeters or rotameters where flow measurement is based on mass or volume. This automatic control reduces operator time by 80 percent. Solid-state components are very reliable, and digital character allows system accuracy to be determined primarily by accuracy of transducers.

Lisle, R. V.↗
NASA NTRS1982

Two-Stage Linearization Circuit

High accuracy is obtained by combining analog and digital corrections. Proximity-sensor linearization circuit has two stages. First-stage linearization is accurate to about 3 percent; accuracy of final output is better than 0.5 percent. By modifying contents of the Programable Read-Only Memory (PROM), circuit can also be used to derive a nonlinear output.

Waldeck, G. C.↗
NASA NTRS1980

Eight microprocessor-based instrument data systems in the Galileo Orbiter spacecraft

Instrument data systems consist of a microprocessor, 3K bytes of Read Only Memory and 3K bytes of Random Access Memory. It interfaces with the spacecraft data bus through an isolated user interface with a direct memory access bus adaptor, and/or parallel data from instrument devices such as registers, buffers, analog to digital converters, multiplexers, and solid state sensors. These data systems support the spacecraft hardware and software communication protocol, decode and process instrument commands, generate continuous instrument operating modes, control the instrument mechanisms, acquire, process, format, and output instrument science data.

Barry, R. C.↗
NASA NTRS1981

Transient upsets in microprocessor controllers

The modeling and analysis of transient faults in microprocessor based controllers are discussed. Such controllers typically consist of a microprocessor, read only memory storing and application program, random access memory for data storage, and input/output devices for external communications. The effects of transient faults on the performance of the controller are reviewed. An instruction level perspective of performance is taken which is the basis of a useful high level program state description of the microprocessor controller. A transition matrix is defined which determines the controller's response to transient fault arrivals.

Glaser, R. E.↗
NASA NTRS1981

RAD hard PROM design study

The results of a preliminary study on the design of a radiation hardened fusible link programmable read-only memory (PROM) are presented. Various fuse technologies and the effects of radiation on MOS integrated circuits are surveyed. A set of design rules allowing the fabrication of a radiation hardened PROM using a Si-gate CMOS process is defined. A preliminary cell layout was completed and the programming concept defined. A block diagram is used to describe the circuit components required for a 4 K design. A design goal data sheet giving target values for the AC, DC, and radiation parameters of the circuit is presented.

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