Optical communication potential.
Lasers for wideband planetary communication, describing heterodyne receiver and transmitter designs
LASER COMMUNICATION↗
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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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Improved electro-optical tracking system
Electro-optical tracking system employs a laser beam illuminating source, an electronic laser beam deflector, and an image dissector photomultiplier. An electronic scanning transmitter and receiver follows rapid movements or accelerations of the target.
Johnson, R. E.↗
Thin-Film Personal Communications and Telemetry System /TFPCTS/, phase C Quarterly report, Sep. 24 - Dec. 24, 1967
Assembly and development of radio frequency portions of transmitter and receiver in thin film personal communications and telemetry system
Source record↗
A reflector feed system with simultaneous, independent, scanning secondary beams.
Parabolic reflector feed system for spacecraft multiple transmitters and receivers with simultaneous, independent secondary beam scanning
Mills, M. K.↗
Versatile telemonitoring system
Small scale versatile multichannel telemonitoring can be installed economically with considerable expansion capabilities. This system contains a data transmitter, control transmitter, control receiver, display of readout units, a sync generator, and some remote control features.
Fergus, R. W.↗
Study of solid-state integrated microwave circuits
Design and development of low noise microwave PCM-FM breadboard telemetry transmitters and receivers
Source record↗
Performance of binary PSK communication systems.
Single channel binary PSK communication systems performance influenced by degree of RF coherence between transmitter and receiver
Oberst, J. F.↗
A variable-step-size robust delta modulator.
Description of an analytically obtained optimum adaptive delta modulator-demodulator configuration. The device utilizes two past samples to obtain a step size which minimizes the mean square error for a Markov-Gaussian source. The optimum system is compared, using computer simulations, with a linear delta modulator and an enhanced Abate delta modulator. In addition, the performance is compared to the rate distortion bound for a Markov source. It is shown that the optimum delta modulator is neither quantization nor slope-overload limited. The highly nonlinear equations obtained for the optimum transmitter and receiver are approximated by piecewise-linear equations in order to obtain system equations which can be transformed into hardware. The derivation of the experimental system is presented.
Song, C. L.↗
Characteristics of individuals with high information potential in government research and development organizations.
In order to study focal individuals within informal communications networks, a special variable was constructed: information potential (IP) was defined as the information-source value placed on an individual by his colleagues. Four hypotheses involving IP were tested in three R&D organizations using questionnaires and pencil-and-paper tests. Results indicated that the individual with high IP used more and different sources of technical information, was seen to be a credible information source and to have a strong ability to associate seemingly unrelated ideas, and was as approachable as the other members of his organization. Four tentative conclusions may be drawn from this study concerning the person with high IP. He is (1) an identifiable individual in several different kinds of organizations; (2) a distinctive information transceiver (transmitter and receiver); (3) both a producer and a catalyst in his own organization; and (4) an extender and an amplifier of information search. To affect the efficiency of informal information flow, the research manager's best hope for positively influencing informal networks lies in the identification and motivation of the special communicators in his organization.
Holland, W. E.↗
The influence of polarization on millimeter wave propagation through rain
A program for the measurement and analysis of the depolarization and differential attenuation that occur when millimeter wave signals propagate through rain is described. Initial data are taken along a 1.43 km path at 17.65 GHz and a supporting theoretical model is developed to relate the propagation effects to rainfall rate and wind velocity. A block diagram of the overall experiment is included. It consists of: (1) an RF system (millimeter wave transmitter and receiver), (2) transmitting and receiving antennas, (3) a weather system with rain gauges, wind sensors, and drop counters, and (4) a digital control, processing, and data storage system.
Bostian, C. W.↗
Synchronization using pulsed edge tracking in optical PPM communication system
A pulse position modulated (PPM) optical communication system using narrow pulses of light for data transmission requires accurate time synchronization between transmitter and receiver. The presence of signal energy in the form of optical pulses suggests the use of a pulse edge tracking method of maintaining the necessary timing. The edge tracking operation in a binary PPM system is examined, taking into account the quantum nature of the optical transmissions. Consideration is given first to pure synchronization using a periodic pulsed intensity, then extended to the case where position modulation is present and auxiliary bit decisioning is needed to aid the tracking operation. Performance analysis is made in terms of timing error and its associated statistics. Timing error variances are shown as a function of system signal to noise ratio.
Gagliardi, R.↗
Coordination procedure for radio relay and communication satellite services
A global rain rate statistic model is used to link microwave propagation statistics to measurable rain statistics in order to develop international telecommunication site criteria for radio relay and communication satellite services that minimize interference between receivers and transmitters. This rain coordination procedure utilizes a rain storm cell size, a statistical description of the rainfall rate within the cell valid for most of the earth's surface, approximations between Raleigh scatter and constancy of precipitation with altitude, and an analytic relation between radar reflectivity and rain rate.
Eckerman, J.↗
Interplex modulation and a suppressed-carrier tracking loop for coherent communications systems
Simple addition to hardware and new mode of operation of transmitter and receiver in coherent, PCM/PSK/PM configuration greatly improves channel efficiency. Procedure reduces amount of power lost to intermodulation products.
Butman, S.↗
Surface electrical properties experiment, part 1
The design evolution, hardware development, and production history of the surface electrical properties (SEP) experiment are discussed. The SEP transmitter and receiver were designed to be used on the lunar surface during the Apollo 17 mission. The equipment was used to measure lunar surface electrical properties over traverses totalling more than 8 kilometers, for a duration of more than 100 minutes. A comprehensive outline of the techniques, is given along with a simplified detailed breakdown of equipment description and function to outline the principles of operation. A history of the design evolution with trade-off criteria and emphasis on changes caused by decisions reached in solving problems inherent in a fast-paced development program are presented from the viewpoint of overall design concept and in detail for each item of deliverable hardware. There is a brief account of lunar operations.
Kupfer, W. S.↗
Channel simulation for optical communication systems
A technique is reported for simulating the signal fading that will be experienced by typical optical communication systems. The desired irradiance or amplitude fading statistics can be simulated by incorporating a linearized optical modulator subsystem between the transmitter and receiver. This technique has been implemented in the design and construction of a laboratory channel simulator. The design of the processing electronics is discussed along with the results of tests performed for each mode of operation.
Tycz, M.↗
Multiple IMU system hardware interface design, volume 2
The design of each system component is described. Emphasis is placed on functional requirements unique in this system, including data bus communication, data bus transmitters and receivers, and ternary-to-binary torquing decision logic. Mechanization drawings are presented.
Landey, M.↗
Propagation predictions and studies using a ray tracing program combined with a theoretical ionospheric model
Radio wave propagation predictions are described in which modern comprehensive theoretical ionospheric models are coupled with ray-tracing programs. In the computer code described, a network of electron density and collision frequency parameters along a band about the great circle path is calculated by specifying the transmitter and receiver geographic coordinates, time, the day number, and the 2800-MHz solar flux. The ray paths are calculated on specifying the frequency, mode, range of elevation angles, and range of azimuth angles from the great circle direction. The current program uses a combination of the Penn State MKI E and F region models and the Mitra-Rowe D and E region model. Application of the technique to the prediction of satellite to ground propagation and calculation of oblique incidence propagation paths and absorption are described. The implications of the study to the development of the next generation of ionospheric models are discussed.
Lee, M. K.↗
CO2 laser doppler systems for the measurement of atmospheric winds and turbulence
Two CO2 laser doppler systems developed by NASA and some results obtained with them are discussed. A continuous wave, monostatic system for short-range wind measurement is described, and direct comparisons between the data obtained with it and with a cup-anemometer/wind vane system and a hot-wire anemometer show excellent agreement between the systems. Improvements being made in three CW, CO2 laser doppler systems, including a filter bank for optimized signal processing and a versatile scanning system, are noted. A pulsed CO2 system for measuring clear air turbulence is described, and results of test performance on board a Convair 990 are presented. It is noted that while the system was able to measure air speed and turbulence, the range of its transmitter-atmosphere-receiver was lower than predicted, and a difference of about 20 to 30 dB existed between the actual and theoretical turbulence measurements. Factors that may account for this loss are listed.
Huffaker, R. M.↗