Realization of optimum interleavers
Optimum symbol sequence interleavers realization taking into account storage capacity and encoding delay
Ramsey, J. L.↗
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Results for “Encoding”
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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Applications of slow-scan television systems to planetary exploration
Slow scan TV systems for planetary exploration, discussing sampled vidicon operation, digital encoding, data storage, signal to noise ratio, future design trends, etc
Salomon, P. M.↗
Coding - A tool for the digital telemetry link
Digital PCM telemetry link coding techniques, discussing encoding-decoding complexity, and concatenated block scheme for channel
Muller, R. M.↗
Error correcting method and apparatus Patent
Description of error correcting methods for use with digital data computers and apparatus for encoding and decoding digital data
Anderson, T. O.↗
Bootstrap hybrid decoding for symmetrical binary input channels
Hybrid decoding technique for symmetrical binary input channels, using bootstrap algorithm across convolutionally encoded information streams
Cocke, J.↗
A measurement of the general relativistic time delay with data from Mariners 6 and 7
The technique for obtaining range measurements is discussed. It involves measuring elapsed time between the transmission of an encoded signal from the ground station and its return from the spacecraft. The theoretical background for the Mariner Mars 1969 relativity test is presented, including computation of orbits and time transformation. Interplanetary and coronal plasma effects on range and Doppler observations at S-band are also considered. The general relativistic propagation delay was measured and a value of 0.997 for the relativity parameter Gamma star was obtained.
Anderson, J. D.↗
The Lick-Gaertner automatic measuring system
The Lick-Gaertner automatic equipment has been designed mainly for the measurement of stellar proper motions with reference to galaxies, and consists of two main components: the survey machine and the automatic measuring engine. The survey machine is used for initial inspection and selection of objects for subsequent measurement. Two plates, up to 17 x 17 inches each, are surveyed simultaneously by means of projection on a screen. The approximate positions of objects selected are measured by two optical screws: helical lines cut through an aluminum coating on glass cylinders. These approximate coordinates to a precision of the order of 0.03mm are transmitted to a card punch by encoders connected with the cylinders.
Vasilevskis, S.↗
Development of an inherently digital transducer
The term digital transducer normally implies the combination of conventional analog sensors with encoders or analog-to-digital converters. Because of the objectionable characteristics of most digital transducers, a program was instituted to investigate the possibility of producing a transducer that is inherently digital, instead of a transducer that is digital in the usual sense. Such a device would have improved accuracy and reliability and would have reduced power and bulk requirements because two processes, sensing and conditioning, would be combined into one processes. A Curie-point-temperature sensor is described that represents realization of the stated goal. Also, a metal-insulator semiconductor is described that does not conform precisely to the program goals but that appears to have applications as a new and interesting transduction device.
Richard, R. R.↗
Delta modulation
The conclusions of the design research of the song adaptive delta modulator are presented for source encoding voice signals. The variation of output SNR vs input signal power/when 8, 9, and 10 bit internal arithmetic is employed. Voice intelligibility tapes to test the 10-bit system are used. An analysis of a delta modulator is also presented designed to minimize the in-band rms error. This is accomplished by frequency shaping the error signal in the modulator prior to hard limiting. The result is a significant increase in the output SNR measured after low pass filtering.
Schilling, D. L.↗
Asynchronous sampling of speech with some vocoder experimental results
The method of asynchronously sampling speech is based upon the derivatives of the acoustical speech signal. The following results are apparent from experiments to date: (1) It is possible to represent speech by a string of pulses of uniform amplitude, where the only information contained in the string is the spacing of the pulses in time; (2) the string of pulses may be produced in a simple analog manner; (3) the first derivative of the original speech waveform is the most important for the encoding process; (4) the resulting pulse train can be utilized to control an acoustical signal production system to regenerate the intelligence of the original speech.
Babcock, M. L.↗
Study of sequential decoding
Sequential decoding problems considered deal with reliable transmission through noise space channels and encoding of space sources for the purpose of data suppression.
Jelinek, F.↗
Advanced Communication System Time domain Modeling Techniques Study (ASYSTD)
ASYSTD activities are presented dealing with signal to noise ratio and bit error rate measurement, distortion measurement, optimization feasibility, and the definition and systems design implications of mean square error for nonideal, orthogonally encoded channels.
Fashano, M.↗
Remote sensing for detection of soil limitations in agricultural areas.
Research was initiated to establish remote sensing techniques for recognizing and mapping soil limitations to land use. Analysis of soils with limitations to land use because of dense subsoil (claypan) and unfavorable topography (convex sloping or depressional areas) was accomplished by experienced soil scientists utilizing a density slicing system. Maps of soil limitations were produced by photographing the color encoded density slicing analysis of an area. The percentage of each soil limitation was measured by the planimeter feature of the density slicing system. The initial results indicate that a density slicing system has great potential not only for delineating areas of similar soil limitations but also for indicating the percentage composition of an area.
Frazee, C. J.↗
A real time programmable data compression system for video data.
Description of the implementation of a data compression system for the real-time operational transmission (through microwave links) of ATS satellite pictures between the command and data acquisition station and a central location for computer processing. The system features the use of general-purpose minicomputers for encoding and decoding; this makes it possible to vary the employed data compression technique and to make simultaneous statistical calculations on the data. Data compression and expansion is accomplished in a manner that does not lower data quality.
Kutz, R. L.↗
Image coding by adaptive block quantization.
A new source encoder called the adaptive block quantizer is proposed for coding data sources that emit a sequence of correlated real numbers with known first- and second-order statistics. Blocks of source output symbols are first classified and then block quantized in a manner that depends on their classification. The system is optimized relative to both the mean square error and the subjective quality of the reconstructed data for a certain class of pictorial data, and the resulting system performance demonstrated. Some interesting relationships between mean square error and subjective picture quality are presented.
Tasto, M.↗
EEG monitoring of a free-swimming diver at a working depth of 15 meters.
Feasibility has been shown for underwater transmission of physiological signals, using frequency modulation of carriers transmitted by return-current-density methods, as part of a personal biotelemetry system. In the prototype system, a standard IRIG subcarrier frequency (2300 Hz) was used. Power requirements, antenna design, and signal attenuation are compatible with free-ranging diving activity at distances up to 15 meters from the receiver. Extrapolation from this study and further developments are expected to substantially increase the range. Advantages of this system include subcarrier compatibility with standard IRIG demodulators using channels 1 through 10, the absence of highly specialized antenna requirements, and reasonable attenuation characteristics for transmission through the turbidity of typical seawater. Moreover, the system would not appear to be depth limited, and to be compatible with use of high-powered transponders of the same type for long-distance transmission, with or without further encoding.
Zweizig, J. R.↗
Time-based priority selection for analog circuits
Unlimited channel capacity multiplexing circuit is hierarchially structured to achieve priority encoding. Circuit could be used for automatic patient monitoring systems and diagnostic test systems in automotive and communications industry.
Fageol, J. D.↗
Performance evaluation of a class of systematic, rate (M-1)/M, convolutional codes
The implementation and performance evaluation are described for a class of rate (M-1)/M, systematic, convolutional codes being decoded with a simple majority logic decoder. The encoding logic appends one parity bit for each PCM telemetry word. It is shown that over the critical range of received PCM telemetry signal-to-noise ratios, this coding procedure produces a net coding gain of from 1.5 to 2.5 db relative to an equal power transmission of uncoded PCM telemetry. Being a low-redundancy systematic code, it is possible to process this data without convolutional decoding with a small rate loss penalty of about 0.5 db.
Greene, E. P.↗