A comparison of time division and Walsh multiplexing for a multiuser communication satellite link
Multiuser satellite communications system transmission capacity, comparing time division with Walsh multiplexing
Bayless, J. W.↗
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Gaussian feedback communication systems with weak noise in the feedback link
Coding for feedback communication system with additive white Gaussian noise, using mean-square estimation error
Sworder, D. D.↗
Receiving antenna installation for ionospheric scattering links
Smearing of the scattered-energy flux density over a range of angles of arrival permits the use of a receiving-end antenna with a height lower than theoretical.
Ashkaliyev, Y. F.↗
Guidance system operations plan for manned CM earth orbital missions using program Skylark 1. Section 2: Data links
A computer program to define the digital uplink and downlink for use in manned command module orbital missions is presented. The subjects discussed are: (1) digital uplink to command module, (2) CMC digital downlink, (3) downlist formats, (4) description of telemetered qualities, (5) flagbits, and (6) effects of Fresh Start (V36) and Hardware Restart on flagword and channel bits.
Hamilton, M. H.↗
Separate physiological roles for two isozymes of pyridine nucleotide-linked glycerol-3-phosphate dehydrogenase in chicken.
The isozymes considered are designated 'liver type' and 'muscle type' based on the tissue of highest concentration. Electrophoretic analysis shows that the liver type is found in small amounts or is undetectable in all tissues studied except liver. The muscle type is found in skeletal muscles and kidney. Presumptive hybrid enzymes occur at low levels in chicken liver and kidney. The tissue distribution of glyceron-3-P dehydrogenase in several birds capable of sustained flight is different than in chicken.
White, H. B., III↗
Telemetry and command, ATS-F's vital link with earth.
The susceptibility of a synchronous satellite to interference as compared with a low orbiting satellite poses a problem for command operations. The Applications Technology Satellites F and G (ATS F & G) are unique in that they will place the first high gain antenna in space that will reduce the need for high powered ground stations. The telemetry and command subsystem provides the necessary versatility required for the conduct of the many sophisticated experiments that will be conducted by the spacecraft. The subsystem provides continuous 24-hr operation of telemetry and command functions with complete redundancy to minimize problems due to RF interference.
Trudell, B. J.↗
Multipath propagation study for L-band, over-ocean, satellite-aircraft communication link
The results are presented of a study of multipath propagation between an aeronautical relay satellite in synchronous earth orbit and an aircraft flying over the ocean. An analytical model for the reflected power is developed and the results of a computer solution are compared with an approximate solution obtained through integration by the method of steepest descent. The computer solution is shown to differ considerably from the approximate solution. Both methods are compared with the limited experimental results available.
Deal, J. H.↗
Economic impact of stimulated technological activity. Part 3: Case study, knowledge additions and earth links from space crew systems
A case study of knowledge contributions from the crew life support aspect of the manned space program is reported. The new information needed to be learned, the solutions developed, and the relation of new knowledge gained to earthly problems were investigated. Illustrations are given in the following categories: supplying atmosphere for spacecraft; providing carbon dioxide removal and recycling; providing contaminant control and removal; maintaining the body's thermal balance; protecting against the space hazards of decompression, radiation, and meteorites; minimizing fire and blast hazards; providing adequate light and conditions for adequate visual performance; providing mobility and work physiology; and providing adequate habitability.
Source record↗
ERTS regional scale overview linking land use and environmental processes in CARETS
A mosaic of ERTS images of the CARETS region has been used to partition the region into zones on the basis of similarity of tones and textures visible at a regional-scale overview. The resulting patterns were compared with existing small scale maps of the region representing relief, land surface forms, geology, soils, vegetation, forest types, and land use. The ERTS-derived zones most closely resemble the patterns on the small scale land use map, suggesting that, at least in a highly developed region such as CARETS, land use is an indicator or resultant surface expression of several interacting environmental processes. These results lend support to the CARETS model of interdisciplinary regional analysis, whereby remote sensor-derived data sets on land use and land use change become the basic data entry into a regional information system to serve regional planners and land managers.
Alexander, R. H.↗
DIALOG: An executive computer program for linking independent programs
A very large scale computer programming procedure called the DIALOG executive system was developed for the CDC 6000 series computers. The executive computer program, DIALOG, controls the sequence of execution and data management function for a library of independent computer programs. Communication of common information is accomplished by DIALOG through a dynamically constructed and maintained data base of common information. Each computer program maintains its individual identity and is unaware of its contribution to the large scale program. This feature makes any computer program a candidate for use with the DIALOG executive system. The installation and uses of the DIALOG executive system are described.
Glatt, C. R.↗
Telemetry link for an automatic salmon migration monitor
The antenna and transmitter described in this report were designed for integration into the remote acoustic assessment system for detection of sockeye salmon in the Bristol Bay region of the Bering Sea. The assessment system configuration consists of an upward directed sonar buoy anchored 150 ft below the surface and attached by cable to a spar buoy tethered some 300 ft laterally. The spar buoy contains a telemetry transmitter, power supply, data processing electronics, an antenna and a beacon light.
Baldwin, H. A.↗
Overshoot suppression in Adaptive Delta Modulator links for video transmission
An overshoot suppression scheme to improve the performance of the Digital Song Adaptive Delta Modulator for picture transmission is described. The overshoot suppression algorithm has been verified using computer simulation on a PDP-8. It is also shown that the additional hardware required for the actual implementation of the algorithm is simpler than those encountered in the literature, and gives better signal tracking accuracy.
Weiss, L.↗
A remote operation quadrupole mass spectrometer using a custom radio-frequency link approach
A commercial quadrupole mass spectrometer (residual gas analyzer, RGA) system has been modified to operate at large separations of its electronics console and sensing head. The methods implemented have made practical applications, as well as operation, of such a system possible for the first time. This advance was stimulated by a need for placing sensors at remote (45 or 60 m) chamber locations for space simulation testing of orbital flight spacecraft. Emphasis is placed on instrument functional requirements and describing the hardware changes and adjustment techniques necessary to assure operation at the extended cable lengths.
Tashbar, P. W.↗
A communication link between the GIM data base and a general application program
Utilizing the extract verb of GIM causes the requested information to be extracted from the GIM base and written on to tape. When the GIM extract has completed, a FORTRAN program is then compiled and executed. This program reads the tape generated by GIM, formats and prints the extracted data on the line printer. When an end of file on the extracted tape is encountered the job is terminated.
Argo, W. V.↗
Digital simulation of a communication link for Pioneer Saturn Uranus atmospheric entry probe, part 2
For abstract, see N75-26198.
Hinrichs, C. A.↗
General-purpose data link
Communications modem comprising transmitter, demodulator, modulator, and receiver is compatible with telephone line, video pair, or 1,250 ohm twisted wire pair. It permits wide range of input and output voltages and flexible data rates, and it has provision for computer interface.
Dinkins, M. J.↗
Dual frequency feed system for the CTS communications link characterization experiment
The developing, testing and installation of a dual frequency feed assembly were described. The feed has been designed to receive signals in the frequency range 11.7 to 12.2 GHz and transmit signals in the frequency range 14.12 GHz plus or minus 250 MHz. Complete performance data of the feed alone and installed in the 15 foot antenna is included herein. Drawings and descriptive information of the feed assembly are also given.
Gill, G. J.↗
The 1976 Helios and Pioneer solar conjunctions-continuing corroboration of the link between Doppler noise and integrated signal path electron density
Observed Doppler noise (rms phase jitter) from the 1976 solar conjunctions of the Helios 1 and 2 and the Pioneer 10 and 11 spacecraft was processed with a recently developed Doppler noise model ISEDB. Good agreement is obtained between the observed data and the model. Correlation is shown between deviations from the ISEDB model and sunspot activity, but it is insufficient to be modeled. Correlation is also shown between ISEDB model deviations for (spacecraft) signal paths on the same side of the sun.
Berman, A. L.↗