Construction of convolutional codes for sequential decoding
Convolutional encoding and sequential decoding of digital data for reliable transmission
Costello, D. J., Jr.↗
SEARCH · Engineering Papers
Results for “Data Digitization”
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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A study of digital techniques for signal processing Semiannual status report, 1 Feb. - 31 Jul. 1970
Adaptive array processing, dynamic programming, digital data transmission, recursive adaptive equalizers, and finite memory communication systems
Boorstyn, R. R.↗
Optics and the Mariner imaging instrument
TV instruments for Mariners 6 and 7 providing analog and digital data, comparing resolutions and accuracies to earth based telescopes and Mariner 4 photographs
Adams, L. A.↗
GCF development
Developing digital data systems for Ground Communications Facility of DSN
Source record↗
Expansion of input capability for electronic scene generator, instruction manual Final report
Characteristics of self-powered, multichannel digital data buffer designed to expand input capability of electronic scene generator
Source record↗
Study of potential applications of digital techniques to the Apollo unified S-band communications system, phase 2 Final report
Digital data processing and error correcting code techniques applied to Apollo unified S band communication system
Source record↗
Technique for measuring time-base errors of magnetic instrumentation recorders/reproducers
Time-base error analysis of magnetically recorded and played back digital data using tape flutter spectral density and amplitude probability distribution measurements and rms time plots
Chan, R. J.↗
Transient augmentation circuit for pulse amplifiers Patent
Digital data handling circuits for pulse amplifiers
Benedict, R. D.↗
Redundant memory organization Patent
Redundant memory for enhanced reliability of digital data processing system
Vinal, A. W.↗
New criteria development
Techniques for selecting performance criteria for voice, video, and digital data systems
Miller, J. C.↗
An evaluation of random analysis methods for the determination of panel damping
An analysis is made of steady-state and non-steady-state methods for the measurement of panel damping. Particular emphasis is placed on the use of random process techniques in conjunction with digital data reduction methods. The steady-state methods considered use the response power spectral density, response autocorrelation, excitation-response crosspower spectral density, or single-sided Fourier transform (SSFT) of the response autocorrelation function. Non-steady-state methods are associated mainly with the use of rapid frequency sweep excitation. Problems associated with the practical application of each method are evaluated with specific reference to the case of a panel exposed to a turbulent airflow, and two methods, the power spectral density and the single-sided Fourier transform methods, are selected as being the most suitable. These two methods are demonstrated experimentally, and it is shown that the power spectral density method is satisfactory under most conditions, provided that appropriate corrections are applied to account for filter bandwidth and background noise errors. Thus, the response power spectral density method is recommended for the measurement of the damping of panels exposed to a moving airflow.
Bhat, W. V.↗
Study of aircraft centered navigation, guidance, and traffic situation system concept for terminal area operation
A concept for automating the control of air traffic in the terminal area in which the primary man-machine interface is the cockpit is described. The ground and airborne inputs required for implementing this concept are discussed. Digital data link requirements of 10,000 bits per second are explained. A particular implementation of this concept including a sequencing and separation algorithm which generates flight paths and implements a natural order landing sequence is presented. Onboard computer/display avionics utilizing a traffic situation display is described. A preliminary simulation of this concept has been developed which includes a simple, efficient sequencing algorithm and a complete aircraft dynamics model. This simulated jet transport was flown through automated terminal-area traffic situations by pilots using relatively sophisticated displays, and pilot performance and observations are discussed.
Anderson, W. W.↗
Information management advanced development. Volume 1: Summary
The information management systems designed for the modular space station are discussed. Subjects presented are: (1) communications terminal breadboard configuration, (2) digital data bus breadboard configuration, (3) data processing assembly definition, and (4) computer program (software) assembly definition.
Gerber, C. R.↗
The structure of jet turbulence producing jet noise.
Measurements are presented that characterize the structure of the jet in both the core and the surrounding annular mixing region. Experiments were carried out in a 1.5-inch diameter subsonic jet at Mach numbers of 0.3, 0.5, and 0.7. The growth of pressure fluctuations within the core from the jet outlet to the end of the jet core was traced through the examination of spectral results. The spectra in the jet core exhibited a peak whose frequency scaled with the jet velocity and the jet diameter which is related to a characteristic dimension of the mixing process. A digital data reduction program was used to calculate the auto- and cross-correlations of axial velocity fluctuations. In the core the cross-correlations were nearly constant in the space-time plane indicating a traveling pressure wave, while in the annular mixing region the cross-correlations exhibited the usual decay in the space-time plane characteristic of convected turbulence.
Wooldridge, C. E.↗
Subminiature micropower digital recorder
High-density digital data, collected periodically or randomly from multiplicity of sensors, are recorded by subminiature recorder. Magnetic recording head is energized with suitable pulsatile signals to reverse polarization on magnetically-sensitive tape while tape is immobilized at recording head. Prior to next recording, set tape so new area of tape is at recording head.
Goodman, R. M.↗
Considerations for the design of an onboard air traffic situation display
The basic concept of remoting information to the cockpit is used to design and develop a computerized airborne traffic situation display device that automatically selects and presents segments of a controller's scope to the aircraft pilot via a narrow band digital data link. These data are integrated with aircraft heading and navigation information to provide a display useful in congested air space. The display can include alphanumerical symbols, air route maps, and controller instructions.
Anderson, R. E.↗
Analytical prediction of digital signal crosstalk of FCC
The results are presented of study effort whose aim was the development of accurate means of analyzing and predicting signal cross-talk in multi-wire digital data cables. A complete analytical model is developed n + 1 wire systems of uniform transmission lines with arbitrary linear boundary conditions. In addition, a minimum set of parameter measurements required for the application of the model are presented. Comparisons between cross-talk predicted by this model and actual measured cross-talk are shown for a six conductor ribbon cable.
Belleisle, A. P.↗
Multi-discipline resource inventory of soils, vegetation and geology
The author has identified the following significant results. Computer classification of natural vegetation, in the vicinity of Big Summit Prairie, Crook County, Oregon was carried out using MSS digital data. Impure training sets, representing eleven vegetation types plus water, were selected from within the area to be classified. Close correlations were visually observed between vegetation types mapped from the large scale photographs and the computer classification of the ERTS data (Frame 1021-18151, 13 August 1972).
Simonson, G. H.↗