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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1968

Simplified, high-speed binary data decoder

Simplified, high-speed decoder of encoded binary data received over a noisy channel is provided in a versatile apparatus that can accommodate more than one particular set of codes. The apparatus is applicable to satellite, lunar, and planetary data transmission.

Anderson, T. O.↗
NASA NTRS2005

Highly Reliable, High-Speed, Unidirectional Serial Data Links

Highly reliable, high-speed, unidirectional serial data-communication subsystems have been proposed to be installed in an upgrade of the computing systems aboard the space shuttles. The basic design concept of these serial data links is also adaptable to terrestrial use in applications in which there are requirements for highly reliable serial data communications. The hardware and software aspects of the architecture of the data links are dictated largely by a requirement, in the original space-shuttle application, for one computer to monitor the memory transactions and memory contents of other computers in real time with high reliability and without reliance on requests for retransmission. To minimize weight while affording a capability to transfer data at a required rate of 2.56 x 10(exp 8) bits per second, it was decided that the links would be serial ones of the fiber-channel type. [Fiber channel denotes a type of serial computer bus that is used to connect a computer (usually a supercomputer) with a high-speed data storage device. Depending on the specific application, the physical connection between the transmitter and receiver could be made via an optical fiber or a twisted pair of wires.] Heretofore, fiber-channel links have ordinarily been bidirectional and have operated under protocols that provide for receiving stations to detect errors and request retransmission when necessary. In the present case, the time taken by processing to request retransmission would conflict with the requirement for real-time transfer of data. To ensure reliability without retransmission, a link according to the proposal would utilize a modified version of the normal fiberchannel character set in conjunction with forward error correction by means of a Reed-Solomon code (see figure). The Reed-Solomon encoding and decoding and the translations between the normal and modified character sets would be effected by logic circuitry external to the fiber-channel transmitter and receiver, which would be commercial off-the-shelf units. The receiving end of the link could detect and correct errors at a rate as high as 4 million times per second, if necessary. The receiver detects uncorrectable double-byte errors. It has been estimated that uncorrectable-error rate would amount to one failure in about 10(exp 19) characters.

Cole, Robert M.↗
NASA NTRS1983

Design of a high-speed digital processing element for parallel simulation

A prototype of a custom designed computer to be used as a processing element in a multiprocessor based jet engine simulator is described. The purpose of the custom design was to give the computer the speed and versatility required to simulate a jet engine in real time. Real time simulations are needed for closed loop testing of digital electronic engine controls. The prototype computer has a microcycle time of 133 nanoseconds. This speed was achieved by: prefetching the next instruction while the current one is executing, transporting data using high speed data busses, and using state of the art components such as a very large scale integration (VLSI) multiplier. Included are discussions of processing element requirements, design philosophy, the architecture of the custom designed processing element, the comprehensive instruction set, the diagnostic support software, and the development status of the custom design.

Milner, E. J.↗
NASA NTRS2003

Signal-Conditioning Amplifier Recorders

Signal-conditioning amplifier recorders (SCAmpRs) have been proposed as a means of simplifying and upgrading the Kennedy Space Center (KSC) Ground Measurement System (GMS), which is a versatile data-acquisition system that gathers and records a variety of measurement data before and during the launch of a space shuttle. In the present version of the GMS system, signal conditioning amplifiers digitize and transmit data to a VME chassis that multiplexes up to 416 channels. The data is transmitted via a high-speed data bus to a second VME chassis where it is available for snapshots. The data is passed from the second VME chassis to a high-speed data recorder. This process is duplicated for installations at two launch pads and the Vehicle Assembly Building (VAB). Since any failure of equipment in the data path results in loss of data, much of the system is redundant. The architecture of the existing GMS limits expansion or any modification to the system to meet changing requirements because of the cost and time required. A SCAmpR-based system is much more flexible. The basis of the simplification, flexibility, and reliability is the shifting of the recording function to the individual amplifier channels. Each SCAmpR is a self-contained single channel data acquisition system, which in its current implementation, has a data storage capacity of up to 30 minutes when operating at the fastest data sampling rates. The SCAmpR channels are self-configuring and self-calibrating. Multiple SCAmpR channels are ganged on printed circuit boards and mounted in a chassis that provides power, a network hub, and Inter-Range Instrument Group (IRIG) time signals. The SCAmpR channels share nothing except physical mounting on a circuit board. All circuitry is electrically separate for each channel. All that is necessary to complete the data acquisition system is a single master computer tied to the SCAmpR channels by standard network equipment. The size of the data acquisition system dictates the requirements for the specific network equipment.

Medelius, Pedro J.↗
NASA NTRS1994

NASCOM system development plan: System description, capabilities, and plans, FY 94-2

The Nascom System Development Plan (NSDP) for FY 94-2 contains 17 sections. It is a management document containing the approved plan for maintaining the Nascom Network System. Topics covered include an overview of Nascom systems and services, major ground communication support systems, low-speed data system, voice system, high-speed data system, Nascom support for NASA networks, Nascom planning for NASA missions, and network upgrade and advanced systems developments and plans.

Source record↗
NASA NTRSDate not supplied

Global Analysis of Nonlinear Second-Mode Development in a Mach-6 Boundary Layer From High-Speed Schlieren Data

The second-mode instability on a 7◦ half-angle sharp cone at Mach 6 is analyzed using high-speed calibrated schlieren imagery at a frame rate near the expected fundamental frequency. Experiments were conducted in the NASA Langley 20-Inch Mach 6 facility at unit Reynolds number between 6.56×106 and 9.71×106 m−1. Time-resolved pixel intensity signals throughout the boundary layer are reconstructed using spatially available data in the schlieren images to recover an effective sampling rate of over 10 MHz; these are then converted to quantitative density gradients using a thin-lens-based calibration technique. A global analysis is performed on the schlieren data to investigate the nonlinear growth of the second-mode fundamental and harmonic content. Point-wise measures of the auto-bicoherence are used to identify specific triadic interactions and the locations of their highest levels of quadratic phase coupling. Significant resonance interactions between the second-mode fundamental and harmonic instabilities were found along with interactions between these and the mean flow. Bispectral mode decomposition is employed to educe the flow structures associated with these interactions. A similar analysis is performed for the power spectrum, with power spectral densities computed for each pixel’s time-series and spectral proper orthogonal decomposition employed to derive the modal structure and energy of the flow at specific frequencies. Comparisons between the bispectral quantities and second-mode power show that nonlinear interactions, particularly resonance interactions, are closely correlated with space-time modulation of disturbances during the nonlinear stage of transition.

boundary layer transition↗
NASA NTRS1981

High-speed multiplexing of keyboard data inputs

A high speed multiplexing system is described in which keyboard entered data is sequentially and automatically sampled by the multiplexing system for input to a computer. A sequencer is provided which sequentially and automatically controls the multiplexer to sample each keyboard input in accordance with a predetermined sampling sequence. Whenever keyboard entered data appears on input lines to the multiplexer, the system inputs the keyboard data to the computer during a brief time interval in which the multiplexer remains at the particular keyboard address or port. Thus, a high speed sampling circuit is provided whereby the only operator action required is data entry through a keyboard. Priority or interrupt systems are not required.

Anderson, T. O.↗
DOE OSTI2019

Radiation-Hardened, High-Speed Parallel VCSEL Links for High-Energy Physics

Vega Wave Systems, Inc. has been awarded a Small Business Innovative Research (SBIR) Phase II proposal to the U.S. Department of Energy entitled “Radiation-Hardened, High-Speed Parallel VCSEL Links For High-Energy Physics.” The technology proposed under this program is a significant advance (up to 4x) in data rate over current optical link technologies under development. Fermilab supports the technology developed under this proposal as a radiation-hardened, cost-effective solution for optical links for the high-speed data communications in High-Energy Physics and agrees to provide consulting and test engineering in support of this program. Fermilab staff will provide consulting services along with high speed testing of modules before and after radiation testing.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS2003

Remote Transmission at High Speed

Omni and NASA Test Operations at Stennis entered a Dual-Use Agreement to develop the FOTR-125, a 125 megabit-per-second fiber-optic transceiver that allows accurate digital recordings over a great distance. The transceiver s fiber-optic link can be as long as 25 kilometers. This makes it much longer than the standard coaxial link, which can be no longer than 50 meters.The FOTR-125 utilizes laser diode transmitter modules and integrated receivers for the optical interface. Two transmitters and two receivers are employed at each end of the link with automatic or manual switchover to maximize the reliability of the communications link. NASA uses the transceiver in Stennis High-Speed Data Acquisition System (HSDAS). The HSDAS consists of several identical systems installed on the Center s test stands to process all high-speed data related to its propulsion test programs. These transceivers allow the recorder and HSDAS controls to be located in the Test Control Center in a remote location while the digitizer is located on the test stand.

Source record↗
NASA NTRS2016

Dynamic Range Enhancement of High-Speed Electrical Signal Data via Non-Linear Compression

Systems and methods for high-speed compression of dynamic electrical signal waveforms to extend the measuring capabilities of conventional measuring devices such as oscilloscopes and high-speed data acquisition systems are discussed. Transfer function components and algorithmic transfer functions can be used to accurately measure signals that are within the frequency bandwidth but beyond the voltage range and voltage resolution capabilities of the measuring device.

Laun, Matthew C.↗
NASA NTRS1976

Selective data segment monitoring system

High speed data monitoring apparatus is described for displaying the bit pattern of a selected portion of a block of transmitted data comprising a shift register for receiving the transmitted data and for temporarily containing the consecutive data bits. A programmable sync detector for monitoring the contents of the shift register and for generating a sync signal when the shift register contains a predetermined sync code is included. A counter is described for counting the data bits input to the shift register after the sync signal is generated and for generating a count complete signal when a selected number of data bits have been input to the register. A data storage device is used for storing the contents of the shift register at the time the count complete signal is generated.

Wirth, M. N.↗
DOE OSTI2023

Implementation of a High-Speed Multichannel Data Acquisition System for Magnetic Diagnostics and Plasma Centroid Position Control in ISTTOK

In tokamak and other fusion devices, magnetic control is the main tool that allows to regulate the plasma current, position and shape; it is in charge of actuating the desired plasma current waveform, steering the plasma position to a given set point and maintain the plasma shape close to a prescribed plasma equilibrium. This work describes the application of several physics concepts and computational tools in order to obtain a novel optimal controller for the plasma centroid position, which has been implemented and tested in the real-time plasma control system at the ISTTOK tokamak. A key point for the development of the new control system was the installation of a recently upgraded hardware, that numerically integrates in real-time the magnetic probes signals.

poloidal field coils↗