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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 271 records · Page 15

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NASA NTRS1970

Laboratory verification optical signal coupling. IMBLMS phase B.4, appendix C, section 12

The design of optical couplers is described for use in the IMBLMS hardwire mode. One coupler transmits data from the bio-belt to the central data system and the other coupler transmits audio frequencies in the opposite direction, from the central data system to the bio-belt. The objective is to isolate the ground system at the body worn bio-belt electronics and the main ground at the central data system, or biomedical and behavioral station. The safety of the subject wearing the bio-belt measuring electronics is the purpose in isolating the wearer from the main system ground.

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NASA NTRS1971

Disaster warning satellite study

The Disaster Warning Satellite System is described. It will provide NOAA with an independent, mass communication system for the purpose of warning the public of impending disaster and issuing bulletins for corrective action to protect lives and property. The system consists of three major segments. The first segment is the network of state or regional offices that communicate with the central ground station; the second segment is the satellite that relays information from ground stations to home receivers; the third segment is composed of the home receivers that receive information from the satellite and provide an audio output to the public. The ground stations required in this system are linked together by two, separate, voice bandwidth communication channels on the Disaster Warning Satellites so that a communications link would be available in the event of disruption of land line service.

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NASA NTRS1972

The Skylab communications system.

Skylab is an experimental manned space station which will be operated by three astronauts intermittently over eight months in 1973. It will be in a 235 nautical mile, 50 degree inclination orbit. The communication system includes an onboard audio distribution hard-line network with 13 stations; a teleprinter for recording messages from the ground; telemetry, voice and television links; an onboard video distribution network. The radio frequencies system also includes radiometer and scatterometer earth-scanning sensors operating at 13.9 GHz and 1.4 GHz. The overall Skylab Program is discussed briefly and the communications system is described in more detail.

Disher, J. H.↗

NASA NTRS1973

Eight-channel telephone telemetry system

Portable telemetry system uses conventional telephone link which eliminates mailing or messenger service between physician and analyst. Transmitter is used by physician; receiver is used by analyst. Each unit is inductively coupled to its respective telephone set, transmitter converting EEG into audio frequency and receiver converting this frequency back to EEG.

Smith, R.↗

NASA NTRS1974

An automated remote marshland water-sampling station

Station may be made to turn on and off remotely in response to radio, audio, photo, or other suitable signals, as well as by hard-wire switching. Station will remain operational under conditions of 4-foot tidal variations, along with 4-foot wave action, and will withstand hurricane-force winds without toppling over.

Thomas, D. F.↗

NASA NTRS1972

Microwave radiometric systems.

Microwave radiometers measure thermal electromagnetic radiation at frequencies ranging over the entire radio spectrum, from audio to infrared. The temperatures of black-body radiators can be measured with sensitivities better than 0.01 K, and with absolute accuracies better than 0.5 K. Radiometric systems have been built with as many as 400 independent spectral channels. Frequency resolutions range from hertz to gigahertz; and integration times range from microseconds to hours. Radiometric systems have operated reliably on the ground, and in balloons, aircraft, and spacecraft, including the 1962 Mariner 2 planetary probe to Venus.

Barath, F. T.↗

NASA NTRS1971

Teleconferencing, an annotated bibliography, volume 3

In this annotated and indexed listing of works on teleconferencing, emphasis has been placed upon teleconferencing as real-time, two way audio communication with or without visual aids. However, works on the use of television in two-way or multiway nets, data transmission, regional communications networks and on telecommunications in general are also included.

Shervis, K.↗

NASA NTRS1974

Demodulator for carrier transducers

A carrier type transducer is supplied with a carrier wave via an audio amplifier, a filter, a frequency divider, and an oscillator. The carrier is modulated in accordance with the parameter being measured by the transducer and is fed to the input of a digital data system which may include a voltmeter. The output of the oscillator and the output of each stage of the divider are fed to an AND or a NAND gate and suitable variable and fixed delay circuits to the command input of the digital data system. With this arrangement, the digital data system is commanded to sample at the proper time so that the average voltage of the modulated carrier is measured. It may be utilized with ancillary circuitry for control of the parameter

Roller, R. F.↗

NASA NTRS1973

Weather dissemination and public usage

The existing public usage of weather information was examined. A survey was conducted to substantiate the general public's needs for dissemination of current (0-12 hours) weather information, needs which, in a previous study, were found to be extensive and urgent. The goal of the study was to discover how the general public obtains weather information, what information they seek and why they seek it, to what use this information is put, and to further ascertain the public's attitudes and beliefs regarding weather reporting and the diffusion of weather information. Major findings from the study include: 1. The public has a real need for weather information in the 0-6 hour bracket. 2. The visual medium is preferred but due to the lack of frequent (0-6 hours) forecasts, the audio media only, i.e., telephone recordings and radio weathercasts, were more frequently used. 3. Weather information usage is sporadic.

Stacey, M. S.↗

NASA NTRS1974

The study of electrical conduction mechanisms

The dielectric response of lunar fines 74241,2 is presented in the audio-frequency range and under lunarlike conditions. Results suggest that volatiles are released during storage and transport of the lunar sample. Apparently, subsequent absorption of volatiles on the sample surface alter its dielectric response. The assumed volatile influence disappear after evacuation. A comparison of the dielectric properties of lunar and terrestrial materials as a function of density, temperature, and frequency indicates that if the lunar simulator analyzed were completely devoid of atmospheric moisture it would present dielectric losses smaller than those of the lunar sample. It is concluded that density prevails over temperature as the controlling factor of dielectric permittivity in the lunar regolith and that dielectric losses vary slowly with depth.

Morrison, H. F.↗

NASA NTRS1974

MSFC Skylab instrumentation and communication system mission evaluation

An evaluation of the in-orbit performance of the instrumentation and communications systems installed on Skylab is presented. Performance is compared with functional requirements and the fidelity of communications. In-orbit performance includes processing engineering, scientific, experiment, and biomedical data, implementing ground-generated commands, audio and video communication, generating rendezvous ranging information, and radio frequency transmission and reception. A history of the system evolution based on the functional requirements and a physical description of the launch configuration is included. The report affirms that the instrumentation and communication system satisfied all imposed requirements.

Adair, B. M.↗

NASA NTRS1973

Automatic measuring device for octave analysis of noise

An automatic decoder is described that counts noise levels by pulse counters and forms audio signals proportional in duration to the total or to one of the octave noise levels. Automatic ten fold repetition of the measurement cycle is provided at each measurement point before the transition to a new point is made.

Memnonov, D. L.↗

NASA NTRS1973

Method of investigation of vibroacoustic characteristics of centrifugal pumps

A method for acoustical diagnostics of pumps is described which consists of taking sonograms of the pump, by means of an audio spectrograph. In distinction from usual analyzers, the spectrograph makes it possible to obtain a three-dimensional image of the signal being analyzed, in which its frequency-amplitude characteristics developed over time are depicted with a resolving power of 0.004 sec. As an example, a sonogram of an electrically driven pump, in the 40-4000 Hz frequency range, is presented. The amplitude ratios are determined on the sonogram by the contrast of individual contours, with an accuracy of 6 db.

Pokrovskiy, B. V.↗

NASA NTRS1974

Feasibility study of a swept frequency electromagnetic probe (SWEEP) using inductive coupling for the determination of subsurface conductivity of the earth and water prospecting in arid regions

Techniques developed for electromagnetic probing of the lunar interior, and techniques developed for the generation of high power audio frequencies were combined to make practical a magnetic inductive coupling system for the rapid measurement of ground conductivity profiles which are helpful when prospecting for the presence and quality of subsurface water. A system which involves the measurement of the direction, intensity, and time phase of the magnetic field observed near the surface of the earth at a distance from a horizontal coil energized so as to create a field that penetrates the earth was designed and studied to deduce the conductivity and stratification of the subsurface. Theoretical studies and a rudimentary experiment in an arid region showed that the approach is conceptually valid and that this geophysical prospecting technique can be developed for the economical exploration of subterranean water resources.

Latorraca, G. A.↗

NASA NTRS1973

Effect of channel errors on delta modulation transmission

We have considered the response of a variable step size delta modulator communication system, to errors caused by a noisy channel. For the particular adaptive delta modulation scheme proposed by Song, Garodnick, and Schilling (1971), we have a simple analytic formulation of the output error propagation due to a single channel error. It is shown that single channel errors cause a change in the amplitude and dc level of the output, but do not otherwise affect the shape of the output waveform. At low channel error rates, these effects do not cause any degradation in audio transmission. Higher channel error rates cause overflow or saturation of the step size register. We present relationships between channel error rate, register size, and the probability of register overflow.

Rosenberg, W. J.↗

NASA NTRS1974

Skylab electronic technological advancements

The present work describes three electronic devices designed for use in the Skylab airlock module: the teleprinter system, the quartz crystal microbalance contamination monitor (QCM), and the speaker. Design considerations, operation, characteristics, and system development are described for these systems, with accompanying diagrams, graphs, and photographs. The teleprinter is a thermal dot printer used to produce hard copy messages by electrically heating print elements in contact with heat-sensitive paper. The QCM was designed to estimate contamination buildup on optical surfaces of the earth resources experiment package. A vibrating quartz crystal is used as a microbalance relating deposited mass to shifts in the crystal's resonant frequency. Audio devices provide communication between crew members and between crew and STDN, and also provide audible alarms, via the caution and warning system, of out-of-limit-conditions.

Hornback, G. L.↗

NASA NTRS1975

Psychological stress measurement through voice output analysis

Audio tape recordings of selected Skylab communications were processed by a psychological stress evaluator. Strip chart tracings were read blind and scores were assigned based on characteristics reported by the manufacturer to indicate psychological stress. These scores were analyzed for their empirical relationships with operational variables in Skylab judged to represent varying degrees of situational stress. Although some statistically significant relationships were found, the technique was not judged to be sufficiently predictive to warrant its use in assessing the degree of psychological stress of crew members in future space missions.

Older, H. J.↗

NASA NTRS1974

Dielectric comparison of lunar and terrestrial fines at lunar conditions

The dielectric properties of lunar fines 74241,2 in the audio-frequency range under lunarlike conditions are presented. Results suggest that volatiles are released during storage and transport of the lunar sample. Apparently, subsequent adsorption of volatiles on the sample surface alters its dielectric response. The assumed volatile influence disappears after evacuation. A comparison of the dielectric properties of lunar and terrestrial materials as a function of density, temperature, and frequency indicates that if the terrestrial sample analyzed were completely devoid of atmospheric moisture, it would present dielectric losses smaller than those of the lunar sample. It is concluded that density prevails over temperature as the controlling factor of dielectric permittivity in the lunar regolith and that dielectric losses vary slowly with depth.

Alvarez, R.↗