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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 523 records · Page 29
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NASA NTRS1972

Low distortion automatic phase control circuit

Circuit for generation and demodulation of quadrature double side band signals in frequency division multiplexing system is described. Circuit is designed to produce low distortion automatic phase control. Illustration of circuit and components is included.

Hauge, G.↗
NASA NTRS1971

System distortion errors in radiorespirometry curves.

Description of a method for evaluating the maximum error producible in the system distortion of a carrier gas type radiorespirometer. The maximum producible error is evaluated on the basis of a second order. The maximum producible decrease in peak height output is calculated as a function of the system's time constant or flow rate by using the system's transfer function and the Laplace transformation equation (Gardner and Barnes, 1961).

Neville, E. D.↗
NASA NTRS1971

Magnetospheric-field distortions observed by OGO 3 and 5.

The rubidium vapor magnetometer data of the scalar magnetic-field intensity obtained by the OGO 3 and 5 satellites are analyzed to study the magnetospheric-field distortions in terms of the observed field magnitude under quiet and slightly disturbed conditions minus the magnitude of the reference geomagnetic field (delta B). Average contours of equal delta Bs are shown in the geomagnetic noon-midnight and dawn-dusk meridian planes for magnetically quiet and slightly disturbed conditions. The equatorial distribution of observed delta Bs as a function of geocentric distance differs substantially from that expected from the well-known models of the quiet-time ring current. Other findings suggest that there must be a population of low-energy particles with substantial total energy near the equator at distances of 2 to 5 earth radii that has not been recognized as having sufficient energy to inflate the magnetic field.

Sugiura, M.↗
NASA NTRS1972

A bound on the rate-distortion function and application to images.

An upper bound on the rate-distortion function for discrete ergodic sources with memory is developed by partitioning the source sample space into a finite number of disjoint subsets and bounding the rates for each subset. The bound depends only on the mean vectors and covariance matrices for the subsets and is easy to compute. It is tighter than the Gaussian bound for sources that exhibit clustering of either the values or covariances of successive source outputs. The bound is evaluated for a certain class of pictorial data using both one-dimensional and two-dimensional blocks of picture elements. Two-dimensional blocks yield a tighter bound than one-dimensional blocks; both result in a significantly tighter bound than the Gaussian bound.

Tasto, M.↗
NASA NTRS1972

Rate distortion from planet to paper.

The overall data link commences with the lens of the spacecraft camera, followed by the telemetry format, and then the passing of the data onto a spacecraft tape recorder for later transmission at a slower rate. The properties of the individual pieces of information are described, and rate distortion theory is discussed. The video channel from the standpoint of information theory, and fidelity criteria for planetary video are considered. Areas for further research are indicated.

Posner, E. C.↗