The dynamic behaviour of a large steerable radio telescope.
Dynamic behavior of large steerable radio telescope, showing structural resonance influence on error detection system
Macinante, J. A.↗
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Results for “error detection”
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Coding - An engineering tool for the digital telemetry link.
Digital telemetry link coding as English language analogy, developing block code scheme combining bit, word and block error detection and correction methods
Muller, R. M.↗
Ground computer test trap
Test trap consists of logic nest of five printed circuit boards, plus power supply within the unit. Device monitors more than one logic area simultaneously, gives visual display of detected error, operates at computer speed, maintains readily available logic description of cards used, and is compatible with existing computer circuitry.
Fondrie, D. G.↗
Man-machine interactive system simplifies computer-aided circuit design
Langley interactive computerized circuit analysis capability /LICCA/ enables designer to draw electronic circuit diagrams on cathode ray tube screen. This information is submitted as input to user-selected circuit analysis program. LICCA accommodates binary logic circuits and circuits with discrete components, and monitors operator's instructions to detect errors.
Bavuso, S. J.↗
Digital fault diagnosis by low-cost arithmetical coding techniques
Error detecting and correcting codes for locating logic faults in digital computers
Avizienis, A.↗
A readily implemented single-error-correcting unit-distance counting code
Unit distance redundant counting code for single error correction or double error detection with digital equipment simplicity advantages
Kautz, W. H.↗
Standard interface definition for avionics data bus systems
Data bus for avionics system of space shuttle, noting functions of interface unit, error detection and recovery, redundancy, and bus control philosophy
Kosmala, A. L.↗
Techniques for improving reliability of computers
Modular design techniques improve methods of error detection, diagnosis, and recovery. Theoretical computer (MARCS (Modular Architecture for Reliable Computer Systems)) study deals with postulated and modeled technology indigenous to 1975-1980. Study developments are discussed.
Cater, W. C.↗
Mathematical analysis for the performance assessment of space communication parameters, IBM-360 version
Development of equations to determine communication capability of pulse or digital transmission link is discussed. Equation specifies probability detection error for one-way transmission. Analysis is conducted on IBM 360 computer using FORTRAN 4.
Grayson, L.↗
Development and testing of the infrared interferometer spectrometer for the Mariner Mars 1971 spacecraft
The design, development and testing of the infrared interferometer spectrometer is reported with emphasis on the unique features of the Mariner instrument as compared to previous IRIS instruments flown on the Nimbus meteorological research satellites. The interferometer functions in the spectral range from 50 microns to 6.3 microns. A noise equivalent radiance of 0.5 X 10 to the -7th power W/sq cm/ster/cm has been achieved. Major improvements that were implemented included the cesium iodide beamsplitter and electronic features to suppress the effect of vibration on the Michelson mirror motion and digital filtering through the summation of increased sampling of the infrared signal. A bit error detection and correction scheme was also implemented in order to recover the science data with a higher level of confidence over the telecommunication link.
Hanel, R. H.↗
A geometrical interpretation of the 2n-th central difference
Many algorithms used for data smoothing, data classification and error detection require the calculation of the distance from a point to the polynomial interpolating its 2n neighbors (n on each side). This computation, if performed naively, would require the solution of a system of equations and could create numerical problems. This note shows that if the data is equally spaced, then this calculation can be performed using a simple recursion formula.
Tapia, R. A.↗
A reliability and comparative analysis of two standby system configurations.
Equations are derived which enable one to calculate the system reliability for parallel or triple modular redundant systems with standby spares. Software error detection is introduced into the TMR/Spares system configuration in order to utilize fully all of the units. An indication of the sensitivity of the system reliability to an increase in the number of spares, partitioning, switching, variations in the powered and unpowered failures rates, and time is presented. A comparison of the parallel and the TMR/Spares system configurations, under similar conditions, is given.
Taylor, D. S.↗
Buffer control unit for computer communications
Unit provides character echoing for keyboard display, parity and syndrome generation (error detection), half or full data-packet generation, automatic retransmission of packets, and keyboard lock-up.
Okinaka, A. K.↗
Precision time distribution within a deep space communications complex
The Precision Time Distribution System (PTDS) at the Golstone Deep Space Communications Complex is a practical application of existing technology to the solution of a local problem. The problem was to synchronize four station timing systems to a master source with a relative accuracy consistently and significantly better than 10 microseconds. The solution involved combining a precision timing source, an automatic error detection assembly and a microwave distribution network into an operational system. Upon activation of the completed PTDS two years ago, synchronization accuracy at Goldstone (two station relative) was improved by an order of magnitude. It is felt that the validation of the PTDS mechanization is now completed. Other facilities which have site dispersion and synchronization accuracy requirements similar to Goldstone may find the PTDS mechanization useful in solving their problem. At present, the two station relative synchronization accuracy at Goldstone is better than one microsecond.
Curtright, J. B.↗
Automatic documentation system extension to multi-manufacturers' computers and to measure, improve, and predict software reliability
The DOMONIC system has been modified to run on the Univac 1108 and the CDC 6600 as well as the IBM 370 computer system. The DOMONIC monitor system has been implemented to gather data which can be used to optimize the DOMONIC system and to predict the reliability of software developed using DOMONIC. The areas of quality metrics, error characterization, program complexity, program testing, validation and verification are analyzed. A software reliability model for estimating program completion levels and one on which to base system acceptance have been developed. The DAVE system which performs flow analysis and error detection has been converted from the University of Colorado CDC 6400/6600 computer to the IBM 360/370 computer system for use with the DOMONIC system.
Simmons, D. B.↗
Fault tolerant computing: A preamble for assuring viability of large computer systems
The need for fault-tolerant computing is addressed from the viewpoints of (1) why it is needed, (2) how to apply it in the current state of technology, and (3) what it means in the context of the Phoenix computer system and other related systems. To this end, the value of concurrent error detection and correction is described. User protection, program retry, and repair are among the factors considered. The technology of algebraic codes to protect memory systems and arithmetic codes to protect memory systems and arithmetic codes to protect arithmetic operations is discussed.
Lim, R. S.↗
Modeling laser velocimeter signals as triply stochastic Poisson processes
Previous models of laser Doppler velocimeter (LDV) systems have not adequately described dual-scatter signals in a manner useful for analysis and simulation of low-level photon-limited signals. At low photon rates, an LDV signal at the output of a photomultiplier tube is a compound nonhomogeneous filtered Poisson process, whose intensity function is another (slower) Poisson process with the nonstationary rate and frequency parameters controlled by a random flow (slowest) process. In the present paper, generalized Poisson shot noise models are developed for low-level LDV signals. Theoretical results useful in detection error analysis and simulation are presented, along with measurements of burst amplitude statistics. Computer generated simulations illustrate the difference between Gaussian and Poisson models of low-level signals.
Mayo, W. T., Jr.↗
Fault-tolerant software for aircraft control systems
Concepts for software to implement real time aircraft control systems on a centralized digital computer were discussed. A fault tolerant software structure employing functionally redundant routines with concurrent error detection was proposed for critical control functions involving safety of flight and landing. A degraded recovery block concept was devised to allow collocation of critical and noncritical software modules within the same control structure. The additional computer resources required to implement the proposed software structure for a representative set of aircraft control functions were discussed. It was estimated that approximately 30 percent more memory space is required to implement the total set of control functions. A reliability model for the fault tolerant software was described and parametric estimates of failure rate were made.
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