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  • Other Sources  (1,969)
  • COMMUNICATIONS AND RADAR  (988)
  • ELECTRONICS AND ELECTRICAL ENGINEERING  (760)
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  • 1975-1979  (1,751)
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  • 1
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    Development of an Aeroservoelastic Model for Gust Load Alleviation of the NASA Common Research Model Wind Tunnel Experiment (2020)
    In:  CASI
    Details
    Publication Date: 2020-01-23
    Description: As aircraft move to using composite materials as their primary structure they become lighter and more flexible as well. This presents some significant challenges in association with gust load alleviation. In this paper we develop an aeroservoelastic model for use in developing controllers that utilize distributed control surfaces for active gust load alleviation in a set of wind tunnel experiments. The model is based on an preexisting aeroelastic wing tunnel model and compares the baseline functionality to it. We also provide simple full state feedback simulations for the model.
    Keywords: Aerodynamics
    Type: AIAA 2020-0211 , ARC-E-DAA-TN76375 , AIAA Scitech 2020 Forum; Jan 06, 2020 - Jan 10, 2020; Orlando, FL; United States
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  • 2
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    Development of Unsteady Pressure-Sensitive Paint Application on NASA Space Launch System (2020)
    In:  CASI
    Details
    Publication Date: 2020-01-17
    Description: The key measurement to acquire for understanding unsteady flow is surface pressure. Unsteady Pressure-Sensitive Paint (uPSP) is an emerging optical technique used in wind tunnel testing to measure fluctuating surface pressures. Recently, tests were conducted on NASAs Space Launch System in NASA Ames Research Centers Unitary Plan Wind Tunnel to determine the aeroacoustics environment and assist in developing the buffet forcing functions. Unsteady PSP data was collected during this test campaign. Steady state PSP data, infrared thermography, shadowgraph, accelerometer data, and dynamic pressure transducer data were also collected. In all 50 TB of data were collected during the three days of testing. During these three days of testing, a repeating transonic and supersonic alpha sweep condition was acquired. This paper presents these two wind tunnel conditions and examines how the temperature influences the PSP data. In the first large demonstration of uPSP in 2015 on an NESC-, AETC-sponsored wind tunnel test, lifetime PSP results highlighted the influence the model temperature had on the PSP data. A best practice of heat soaking the model before acquiring calibration images was followed during the test campaign presented in this paper. An infrared thermography camera and thermocouples were installed in the model to collect more details of the model surface temperature. Data processing schemes for uPSP are still in development but will be briefly presented here as well.
    Keywords: Aerodynamics
    Type: ARC-E-DAA-TN76119 , AIAA SciTech Forum; Jan 06, 2020 - Jan 10, 2020; Orlando, FL; United States
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  • 3
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    Inflight lightning characteristics measurement system (1979)
    In:  CASI
    Details
    Publication Date: 2005-04-28
    Description: A research data-gathering system being developed for inflight measurement of direct and nearby lightning strike characteristics is described. Wideband analog recorders used to record the lightning scenario are supplemented with high-sample-rate digital transient recorders with augmented memory capacity for increased time resolution of specific times of interest. The endless-loop data storage technique employed by the transient recorders circumvents problems associated with oscilloscopic techniques and allows unattended operation. System integrity and immunity from induced effects is accomplished by fiber-optics signal-transmission links, shielded system enclosures, and the use of a dynamotor for power system isolation.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Florida Inst. of Technol. FAA-Florida Inst. of Technol. Workshop on Grounding and Lightning Technol.; p 105-111
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  • 4
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    Propagation predictions for the HF-range by the Research Institute of the Deutsche Bundespost (1979)
    In:  CASI
    Details
    Publication Date: 2009-11-16
    Description: Long term and short term HF propagation prediction service is described. The long term prediction method is computer based. The short term prediction method is still a manual method which relies mainly on a number of continuous field strength recordings and on the forecaster's ability to interpret the recordings and to combine this information with all available solar-geophysical data. Examples of the predictions are given and are compared with actually observed HF propagation conditions.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 25-43
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  • 5
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    Waveguide arc study (1979)
    In:  CASI
    Details
    Publication Date: 2006-06-01
    Description: Research on waveguide arcs is presented as well as an evaluation on an arc detector. Ways of improving the radio frequency arc generation include methods of generating RF arcs inside the resonator. Dc nitrogen arcs were used to study a spectroradiometer. The spectral strucutres obtained provide a general sketch of spectral distribution and their relative magnitude. The upgrading of a transmitter test light and the simulation of an LED array are reported.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Deep Space Network; p 196-203
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  • 6
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    A circuit model for electromagnetic properties of waveguide arcs (1979)
    In:  CASI
    Details
    Publication Date: 2006-06-01
    Description: A dielectric model of waveguide arcs is presented to relate measurable electromagnetic quantities to the physical parameters characterizing the breakdown process.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 193-195
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  • 7
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    Assessment of 20 kW S-band transmitter (1979)
    In:  CASI
    Details
    Publication Date: 2006-06-01
    Description: The performance history of the 20-kW S-band transmitter, installed at three 64-meter antennas and six 26-meter antennas in the DSN, is reviewed. A number of failures and discrepancy reports are characteristic of the wearout phase of a failure curve. The type of failures are reviewed and four options toward reducing the number and cost of failures are reviewed. These are: existing (no change), refurbish, redesign and replacement. The options are compared on a ten year life cycle cost basis using FY77 expenditures for existing equipment as a base. It was concluded that benefits, in terms of reduction of outrage time, increase with an increase of expenditure toward improvement.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 186-192
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  • 8
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    Microwave time delays in the DSN 34- and 64-meter antennas (1979)
    In:  CASI
    Details
    Publication Date: 2006-06-01
    Description: The results and methods used to derive data for the recent changes to the DSN 34- and 64-m stations at both S- and X-band frequencies are presented.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 183-185
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  • 9
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    DSS 13 antenna monitor system (1979)
    In:  CASI
    Details
    Publication Date: 2006-06-01
    Description: The development of a monitor system for the DSS 13 antenna is presented. The system checks for accumulator pressures, differential pressures, wind velocity, power supplies, fluid temperatures, and fluid levels. It was concluded that the system performed properly in high winds and correctly reported all malfunctions.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 138-140
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  • 10
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    Carrier tracking loop performance in the presence of strong CW interference (1979)
    In:  CASI
    Details
    Publication Date: 2006-06-01
    Description: Research on the behavior of the carrier tracking loop exposed to a continuous wave irradiation along with Bruno's closed form of approximation for the loop phase error are described.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 130-137
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  • 11
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    Costas loop demodulation of suppressed carrier BPSK signals in the DSN environment: Experimental results obtained at TDL (1979)
    In:  CASI
    Details
    Publication Date: 2006-06-01
    Description: Suppressed carrier binary phase-shift keyed (BPSK) signalling is currently being considered as a design alternative for future DSN telemetry in the multimegabit range. Carrier tracking of such signals is usually achieved by a Costas loop, as opposed to the ordinary phase lock loop. A Costas loop capable of demodulating BPSK signals with data rates up to 1 Msps was designed and constructed and its Doppler tracking performance with respect to a Block 3 receiver was tested at the Telecommunications Development Laboratory (TDL). The compatibility of suppressed carrier signalling with the current radiometric system, specifically Doppler tracking and ranging, was investigated. The experimental results obtained to-date with respect to Doppler tracking are presented.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 94-104
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  • 12
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    Feasibility of inertialess conscan utilizing modified DSN feedsystems (1979)
    In:  CASI
    Details
    Publication Date: 2006-06-01
    Description: The closed-loop conical-scan (conscan) technique has proven to be a useful method for pointing the DSN antennas more accurately than is possible by open-loop methods. As presently implemented, the antenna beam is scanned about the received signal direction by physical movement of the antenna. While straightforward, this approach has at least two disadvantages. Firstly, because of structural distortions, finite angle encoder resolution, and drive servo response, the actual antenna beam direction only approximates the commanded beam direction. Secondly, because of the large mass moved during scan, the rate of scan is severely restricted. If there are significant gain or signal level variations during a scan period, the conscan system interprets these variations as antenna pointing error. Both of these disadvantages would be alleviated in an inertialess conscan system in which the beam scanning was performed electronically. Recently, standard JPL antenna feedhorn software was upgraded to calculate, among other things, asymmetric corrugated horn radiation patterns of the type that would be needed for electronic beam scan. The required horn excitation is discussed and the results were described.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 85-93
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  • 13
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    Antenna feedhorn software upgrade (1979)
    In:  CASI
    Details
    Publication Date: 2006-06-01
    Description: The HYBRIDHORN computer program was developed to serve as an item of general purpose antenna feedhorn design and analysis software. The formulation contains a small flare angle approximation which is subject to question for designs such as the S- and X-band feedhorn. Additionally, the original formulation did not allow azimuthal variation indexes other than unity. The HYBRIDHORN program was upgraded to correct both of these deficiencies. A large flare angle formulation was found. In the upgrade, all of the major program elements were converted to Univac 1108 compatible structured FORTRAN (SFTRAN) for ease of software maintenance. The small and large angle formulations are described and sample numerical results are presented.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 75-84
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  • 14
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    A transmission line phase stabilizer (1979)
    In:  CASI
    Details
    Publication Date: 2006-06-01
    Description: To meet the phase stability requirements of certain experiments performed with the Deep Space Network, transmission lines carrying reference signals must be stabilized to reduce changes in their electrical length due to mechanical movement or changes in ambient temperature. A transmission line phase stabilizer being developed at JPL to perform this function is described.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Deep Space Network; p 67-71
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  • 15
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    Some effects of quantization on a noiseless phase-locked loop (1979)
    In:  CASI
    Details
    Publication Date: 2006-06-01
    Description: If the VCO of a phase-locked receiver is to be replaced by a digitally programmed synthesizer, the phase error signal must be sampled and quantized. Effects of quantizing after the loop filter (frequency quantization) or before (phase error quantization) are investigated. Constant Doppler or Doppler rate noiseless inputs are assumed. The main result gives the phase jitter due to frequency quantization for a Doppler-rate input. By itself, however, frequency quantization is impractical because it makes the loop dynamic range too small.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 58-66
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  • 16
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    Recovering the spectrum of a narrow-band process from syncopated samples (1979)
    In:  CASI
    Details
    Publication Date: 2006-06-01
    Description: A nonuniform sampling strategy, phase quadrature sampling, in which a process of bandwith B is sampled at rate B in each of two channels where the two channels are pi/2 out of phase at frequency B is described. Phase quadrature sampling is a special case of sampling, where the phase between channels is fixed but arbitrary. A simple method for recovering the spectrum of the input process from syncopated samples is derived. The derivation indicates what values of phase between channels result in lossless sampling.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 47-50
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  • 17
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    Effects of D region ionization on radio wave propagation (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The effects of anomalous D region ionization upon radio wave propagation are described for the main types of disturbances: sudden ionospheric disturbances, relativistic electron events, magnetic storms, auroral disturbances, polar cap events, and stratospheric warmings. Examples of radio wave characteristics for such conditions are given for the frequencies between the extremely low (3-3000 Hz) and high (3-30 MHz) frequency domains. Statistics on the disturbance effects and radio wave data are given in order to contribute towards the evaluation of possibilities for predicting the radio effects.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 617-654
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  • 18
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    Forecasts of geomagnetic activities and HF radio propagation conditions made at Hiraiso/Japan (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The Hiraiso Branch of RRL prediction techniques are summarized separately for the 27 day recurrent storm and the flare-associated storm. The storm predictions are compared with the actual geomagnetic activities in two ways. The first one is the comparison on a day to day basis. In the second comparison, the accuracy of the storm predictions during 1965-1976 are evaluated. In addition to the storm prediction, short-term predictions of HF radio propagation conditions are conducted at Hiraiso. The HF propagation predictions are briefly described as an example of the applications of the magnetic storm prediction.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 182-204
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  • 19
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    Estimation of solar flame influence on radio circuit transmission loss (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: A provisional method for determining the hours and frequencies at which solar flares cause major radiopath absorption increase is presented. This technique is incorporated in a computer program for monthly radio propagation prediction.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 67-71
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  • 20
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    PROPHET: An applicaton of propagation forecasting principles (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: A propagation assessment and forecasting terminal, PROPHET, is described. The terminal is a key element of the environmental prediction and assessment system which uses real time solar/geophysical data to provide real time knowledge of propagation conditions. The terminal uses models to translate data from satellite and ground based sources into performance predictions for specific systems.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 312-321
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  • 21
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    Radio disturbance warning issuance system (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: A radio disturbance warning issuance system was introduced in the Hiraiso Branch of the Radio Research Laboratories in 1972 to reconstruct the current radio disturbance warning service as a social information service. A description of the new ideas which were experimentally systematized by means of an electronic computer is presented.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 223-228
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  • 22
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    Ionosphere-reflected propagation (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The predictability of those ionospheric parameters relevant to ionosphere-reflected communications is considered along with their optimum utilization. Several excellent original articles and review papers which have been published from time to time dealing with the long term and short term forecasting of ionospheric parameters, radio systems, and modelling needs for ionospheric communications, are covered.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 203-216
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  • 23
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    Transionospheric propagation predictions (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The current status and future prospects of the capability to make transionospheric propagation predictions are addressed, highlighting the effects of the ionized media, which dominate for frequencies below 1 to 3 GHz, depending upon the state of the ionosphere and the elevation angle through the Earth-space path. The primary concerns are the predictions of time delay of signal modulation (group path delay) and of radio wave scintillation. Progress in these areas is strongly tied to knowledge of variable structures in the ionosphere ranging from the large scale (thousands of kilometers in horizontal extent) to the fine scale (kilometer size). Ionospheric variability and the relative importance of various mechanisms responsible for the time histories observed in total electron content (TEC), proportional to signal group delay, and in irregularity formation are discussed in terms of capability to make both short and long term predictions. The data base upon which predictions are made is examined for its adequacy, and the prospects for prediction improvements by more theoretical studies as well as by increasing the available statistical data base are examined.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 217-245
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  • 24
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    Induced electric currents in the Alaska oil pipeline measured by gradient, fluxgate, and SQUID magnetometers (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The field gradient method for observing the electric currents in the Alaska pipeline provided consistent values for both the fluxgate and SQUID method of observation. These currents were linearly related to the regularly measured electric and magnetic field changes. Determinations of pipeline current were consistent with values obtained by a direct connection, current shunt technique at a pipeline site about 9.6 km away. The gradient method has the distinct advantage of portability and buried- pipe capability. Field gradients due to the pipe magnetization, geological features, or ionospheric source currents do not seem to contribute a measurable error to such pipe current determination. The SQUID gradiometer is inherently sensitive enough to detect very small currents in a linear conductor at 10 meters, or conversely, to detect small currents of one amphere or more at relatively great distances. It is fairly straightforward to achieve imbalance less than one part in ten thousand, and with extreme care, one part in one million or better.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 182-192
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  • 25
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    Prediction of solar induced currents and effects on power transmission systems in central Canada (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The auroral-electrojet zone covers three quarters of Manitoba and consequently, solar storms strongly affect transmission lines. Harmonics are generated at transformers due to the saturation of their cores by induced currents, and the level of harmonics produced may cause malfunction of control relays, and yield unacceptable distortions in normal ac waveforms. The expected effects of long ac transmission systems were studied with emphasis on a 500 kv line to be built from Winnipeg to Minneapolis-St. Paul. Spectral analysis of induced current records from Manitoba Hydro's LaVerendrye station and magnetograms from IMS stations in Manitoba were used along with results of Campbell's work on the Alaskan pipeline induction problem (1978) in order to predict periodic and surge currents. It is concluded that the surge currents will produce significant levels of harmonics and corresponding operating problems during magnetic storms.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 162-171
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  • 26
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    Harmonics of 60 Hz in power systems caused by geomagnetic disturbances (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Simultaneous VLF/ULF observations carried out near Winnipeg, Manitoba show that geomagnetic disturbances control the behavior of harmonics of 60 Hz man-made electric power. The harmonics of 60 Hz detected by the VLF receiver are at multiples of 180 Hz, indicating that they originated from a 3 phase ac power system. Under geomagnetically quiet conditions, only odd harmonics of 70 Hz were detected. In disturbed conditions, both odd and even harmonics were excited. The strength of each harmonic changed concurrently with geomagnetic pulsation (ULF) activity. These findings seem to indicate that a portion of telluric currents shunted into the power line system through the neutrals of the Y-connected transformers give rise to a dc bias to the transformer core materials and that it distorts their hysteresis loops, activating harmonics of 60 Hz power. A mathematical proof is given that a hysteresis loop having a point of symmetry generates odd harmonics only, whereas loops lacking in point-symmetry generally give rise to both odd and even harmonics. A general formula was obtained to calculate the strength of each harmonic based on the shape of the hysteresis loop.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 172-181
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  • 27
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    The problem of solar induced currents (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The production of surface electric fields by geomagnetic variations is discussed with reference to magnetotelluric theory; and evidence is presented to show that the severity of solar-induced currents (SIC) at Cornerbrook, Newfoundland is due to channeling of currents induced in the sea through a region adjacent to the power line. An 'isolated loop' approximation is proposed for calculating the quasi-dc currents produced in the power system by the surface electric fields. Identification of the processes causing the geomagnetic perturbations responsible for SIC would be aided by investigation of the local time dependence of SIC occurrence. Such knowledge could potentially be used to provide several hours warning of SIC.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 149-161
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  • 28
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    Magnetic storm effects in electric power systems and prediction needs (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Geomagnetic field fluctuations produce spurious currents in electric power systems. These currents enter and exit through points remote from each other. The fundamental period of these currents is on the order of several minutes which is quasi-dc compared to the normal 60 Hz or 50 Hz power system frequency. Nearly all of the power systems problems caused by the geomagnetically induced currents result from the half-cycle saturation of power transformers due to simultaneous ac and dc excitation. The effects produced in power systems are presented, current research activity is discussed, and magnetic storm prediction needs of the power industry are listed.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 137-148
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  • 29
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    Radio propagation prediction services in Japan (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Japanese prediction services for HF radio communications are outlined in relation to prediction method, performance and evaluation. The current prediction is based on the CCIR interim method with some modifications matching to a computer system. The principal service is the monthly median prediction issued regularly three months in advance for various communication circuits. A daily prediction for short distance circuits is being prepared by using real time ionospheric sounding data. An evaluation theory and practice is expected to be introduced in the future prediction service.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 212-222
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  • 30
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    Long term solar activity and ionospheric prediction services rendered by the National Physical Laboratory, New Delhi (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The data base used in solar and ionospheric prediction services is described. Present prediction techniques are discussed and compared with actual observations. Future prediction techniques using computers are also discussed.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 118-133
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  • 31
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    The French short term radiopropagation predictions in the decameter band (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Weekly and daily predictions of the ionospheric characteristics relevant to radio propagation are considered. A description of the techniques involved is given as well as examples showing how the prediction messages are prepared. The short term predictions are confined to restricted geographical areas and are relevant to radio circuits whose terminators are both located inside the same zone. They can be used with a reasonable approximation for circuits less than 3000 km of length whose reflection point lies within a given zone.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 12-24
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  • 32
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    Heat pipe cooled power magnetics (1979)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A high frequency, high power, low specific weight (0.57 kg/kW) transformer developed for space use was redesigned with heat pipe cooling allowing both a reduction in weight and a lower internal temperature rise. The specific weight of the heat pipe cooled transformer was reduced to 0.4 kg/kW and the highest winding temperature rise was reduced from 40 C to 20 C in spite of 10 watts additional loss. The design loss/weight tradeoff was 18 W/kg. Additionally, allowing the same 40 C winding temperature rise as in the original design, the KVA rating is increased to 4.2 KVA, demonstrating a specific weight of 0.28 kg/kW with the internal loss increased by 50W. This space environment tested heat pipe cooled design performed as well electrically as the original conventional design, thus demonstrating the advantages of heat pipes integrated into a high power, high voltage magnetic. Another heat pipe cooled magnetic, a 3.7 kW, 20A input filter inductor was designed, developed, built, tested, and described. The heat pipe cooled magnetics are designed to be Earth operated in any orientation.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: TRW-33572-6001-RU-00 , NASA-CR-159659
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    Multilayer self-structured bubble memories (1979)
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    Publication Date: 2011-08-17
    Description: Research work on multilayer self-structured bubble memories is at an early stage. The coupling of bubbles to stripes is investigated theoretically and experimentally and shown to be adequate for propagation. Propagation of stripes is demonstrated both by current access and field access techniques. These propagation techniques are of prime interest because they can eliminate most photographic features from the storage area. Multilayer films offer great promise for higher-capacity higher-density memories in which most of the photolithography has been eliminated and the minimum feature size of much of the remaining has been increased. Furthermore, stripe propagation can be carried out with current access, providing a significant reduction in packaging cost and power consumption over field access devices.
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  • 34
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    LaF3 insulators for MIS structures (1979)
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    Publication Date: 2011-08-17
    Description: Thin films of LaF3 deposited on Si or GaAs substrates have been observed to form blocking contacts with very high capacitances. This results in comparatively hysteresis-free and sharp C-V (capacitance-voltage) characteristics for MIS structures. Such structures have been used to study the interface states of GaAs with increased resolution and to construct improved photocapacitive infrared detectors.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Applied Physics Letters; 34; June 1
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  • 35
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    Airborne East Coast/Midwest urban survey at 121.5/243 MHz (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Results of an airborne RF interference measurement survey of the emergency-distress, Search and Rescue frequency bands at 121.5 and 243 MHz at an altitude of 25,000 ft over the U.S. East Coast and Midwest urban areas are presented. Included are a series of minutely median profile plots of antenna-noise temperature computed from RF interference power measurements at the output terminal of a quarter-wavelength monopole antenna, for both daytime and nighttime observations. The greatest value, 450,000 K, of minutely median temperature was recorded over New York City at 121.5 MHz during the day. East Coast urban areas exhibited a day-night effect at 121.5 MHz, where nighttime observations had a median value of 8.6-dB below daytime values; Midwest counterparts did not exhibit a significant day-night effect at 121.5 MHz.
    Keywords: COMMUNICATIONS AND RADAR
    Type: IEEE Transactions on Electromagnetic Compatibility; EMC-21; May 1979
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  • 36
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    Shot-noise in resistive-diode mixers and the attenuator noise model (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The representation of a pumped exponential diode, operating as a mixer, by an equivalent lossy network, is reexamined. It is shown that the model is correct provided the network has ports for all sideband frequencies at which (real) power flow can occur between the diode and its embedding. The temperature of the equivalent network is eta/2 times the physical temperature of the diode. The model is valid only if the series resistance and nonlinear capacitance of the diode are negligible. Expressions are derived for the input and output noise temperature and the noise-temperature ratio of ideal mixers. Some common beliefs concerning noise-figure and noise-temperature ratio are shown to be incorrect.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Microwave Theory and Techniques; MTT-27; Feb. 197
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  • 37
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    Solving the current element problem over lossy half-space without Sommerfeld integrals (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: An approach is presented for efficient computation of the vector potentials arising in the problem of a current element radiating over a lossy half-space. The present approach departs from the conventional ones in that it works primarily with the transform domain representations rather than with the Sommerfeld integrals which are the corresponding spatial domain counterparts. The key step in the present method is to approximate the transforms using a suitable approximation which is valid for a wide range of parameters of practical interest. The approximated transforms can be inverted in a closed form for the horizontal component of the vector potentials and can be expressed in a computationally efficient form for the vertical component. Numerical results illustrating the accuracy of the method are presented and some estimates of comparative computational times are also included.
    Keywords: COMMUNICATIONS AND RADAR
    Type: IEEE Transactions on Antennas and Propagation; AP-27; Nov. 197
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  • 38
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    A matrix solution for the simulation of magnetic fields with ideal current loops (1979)
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    Publication Date: 2011-08-17
    Description: A matrix formulation is presented for describing axisymmetric magnetic field data with ideal current loops. A computer program written in APL is used to invert the matrix and hence to solve for the coil strengths which are used to represent the field data. Examples are given of the coil representation for (1) measured magnetic data, (2) refocusing fields, and (3) PPM focusing fields.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Electron Devices; ED-26; Oct. 197
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  • 39
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    Thermionic cathode life-test studies (1979)
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    Publication Date: 2011-08-17
    Description: A NASA-Lewis Research Center program for life testing commercial, high-current-density thermionic cathodes has been in progress since 1971. The purpose of the program is to develop long-life power microwave tubes for space communications. Four commercial-type cathodes are being evaluated in this investigation. They are the 'Tungstate', 'S' type, 'B' type, and 'M' type cathodes, all of which are capable of delivering 1 A/ sq cm or more of emission current at an operating temperature in the range of 1000-1100 C. The life test vehicles used in these studies are similar in construction to that of a high-power microwave tube and employ a high-convergence electron-gun structure; in contrast to earlier studies that used close-space diodes. These guns were designed for operation at 2 A/sq cm of cathode loading. The 'Tungstate' cathodes failed at 700 h or less and the 'S' cathode exhibited a lifetime of about 20,000 h. One 'B' cathode has failed after 27,000 h, the remaining units continuing to operate after up to 30,000 h. Only limited data are now available for the 'M' cathode, because only one has been operated for as long as 19,000 h. However, the preliminary results indicate the emission current from the 'M' cathode is more stable than the 'B' cathode and that it can be operated at a true temperature approximately 100 C lower than for the 'B' cathode.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Electron Devices; ED-26; Oct. 197
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  • 40
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    Analysis of the interaction of an electron beam with a solar cell. III - The effect of spacial variations of the number density of recombination centers on SEM measurements (1979)
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    Publication Date: 2011-08-17
    Description: By means of an exactly soluble model the short circuit current generated by a scanning electron microscope in a P-N junction has been determined in cases where the trap density is inhomogeneous. The diffusion length for minority carriers becomes then dependent on the spacial coordinates. It is shown that in this case the dependence of the Isc on characteristic parameters as cell thickness, distance of the beam excitation spot from ohmic contacts, etc., becomes very intricate. This fact precludes the determination of the local diffusion length in the usual manner. Although the model is somewhat simplified in order to make it amenable to exact solutions, it is nevertheless realistic enough to lead to the conclusion that SEM measurements of bulk transport parameters in inhomogeneous semiconductor material are impractical since they may lead to serious errors in the interpretation of the data by customary means.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Solid-State Electronics; 22; Sept
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  • 41
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    Digital techniques for ULF wave polarization analysis (1979)
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    Publication Date: 2011-08-17
    Description: Digital power spectral and wave polarization analysis are powerful techniques for studying ULF waves in the earth's magnetosphere. Four different techniques for using the spectral matrix to perform such an analysis have been presented in the literature. Three of these techniques are similar in that they require transformation of the spectral matrix to the principal axis system prior to performing the polarization analysis. The differences in the three techniques lie in the manner in which determine this transformation. A comparative study of these three techniques using both simulated and real data has shown them to be approximately equal in quality of performance. The fourth technique does not require transformation of the spectral matrix. Rather, it uses the measured spectral matrix and state vectors for a desired wave type to design a polarization detector function in the frequency domain. The design of various detector functions and their application to both simulated and real data will be presented.
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  • 42
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    Calculated scan characteristics of a large spherical reflector antenna (1979)
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    Publication Date: 2011-08-17
    Description: A previously published numerical method to calculate the radiation properties of parabolic reflectors has been modified to also include very large spherical reflectors. The method has been verified by comparing the calculated and the measured results for a 120-wavelength spherical reflector.
    Keywords: COMMUNICATIONS AND RADAR
    Type: IEEE Transactions on Antennas and Propagation; AP-27; May 1979
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  • 43
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    False lock performance of quadriphase receivers (1979)
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    Publication Date: 2011-08-17
    Description: Quadriphase receivers, like biphase receivers, have the ability to false lock on a sideband on the data modulation. The theory associated with this phenomenon for receivers of binary phase-shift-keying (BPSK), using Costas loop demodulation, has recently been documented in the literature. This paper considers the corresponding theory for receivers of balanced quadriphase-shift-keying (QPSK) employing a quadriphase Costas loop (or equivalent fourth-power loop) for demodulation. Specific closed form expressions for false lock performance are developed and numerically evaluated for the particular case of single pole arm filters and an NRZ data format for each of the two statistically independent quadrature modulations.
    Keywords: COMMUNICATIONS AND RADAR
    Type: IEEE Transactions on Communications; COM-27; Nov. 197
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  • 44
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    Analytical prediction and experimental verification of TWT and depressed collector performance using multidimensional computer programs (1979)
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    Publication Date: 2011-08-17
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Electron Devices; ED-26; Oct. 197
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  • 45
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    90- to 93-percent efficient collector for operation of a dual-mode traveling-wave tube in the linear region (1979)
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    Publication Date: 2011-08-17
    Description: An axisymmetric multistage depressed collector was evaluated in conjunction with a dual-mode TWT. Collector performance optimizations for the TWT operation in the linear range were stressed. Measured collector efficiencies in excess of 90 percent led to dramatic improvements in TWT overall efficiency.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Electron Devices; ED-26; Oct. 197
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  • 46
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    Efficiency enhancement of coupled-cavity TWT's through cavity resonance tapering (1979)
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    Publication Date: 2011-08-17
    Description: The paper examines efficiency enhancement of coupled-cavity traveling-wave tube (TWT) through cavity resonance tapering. Beam-wave resynchronization through circuit velocity reduction is used for TWT efficiency enhancement, with circuit velocity reduction in coupled cavity TWT's accomplished through period tapering. However, the amount of the latter is limited by the stability considerations, so that beyond a critical value of velocity reduction, the tube may be subject to zero drive oscillations originating in the velocity taper region. The coupled-cavity resonance tapering allows the velocity reduction to continue beyond the limit of stable period tapering, and it is accomplished by a gradual reduction in the cavity resonance frequency, with the period and the circuit bandwidth unchanged. The advantages of cavity resonance tapering vs period tapering are discussed, and test data are presented with the results of large-signal computer calculations. It is shown that cavity resonance tapering can produce efficiencies as period tapering without incurring the same risk of lower band-edge oscillations.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Electron Devices; ED-26; Oct. 197
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  • 47
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    Digital and analog communication systems (1979)
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    Publication Date: 2011-08-17
    Description: The book presents an introductory treatment of digital and analog communication systems with emphasis on digital systems. Attention is given to the following topics: systems and signal analysis, random signal theory, information and channel capacity, baseband data transmission, analog signal transmission, noise in analog communication systems, digital carrier modulation schemes, error control coding, and the digital transmission of analog signals.
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  • 48
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    Two-dimensional representations of axisymmetric fields for computer calculations (1979)
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    Publication Date: 2011-08-17
    Description: An accurate representation of axisymmetric fields has been devised by extending the method of ideal current loops to off-axis fields. It is assumed that the data to be simulated are available through measurements or through a solution of a boundary value problem. The method provides an algebraic expression for the fields throughout a two-dimensional region of interest and eliminates the need for the axial expansion formula in approximating off-axis fields. The use of Gaussian and other functions as alternatives to the coil function is proposed. Examples of the technique in simulating a periodic permanent magnet (PPM) focusing field are presented and compared with a Fourier analysis of the problem.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Electron Devices; ED-26; Nov. 197
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  • 49
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    Annual Conference on Nuclear and Space Radiation Effects, 16th, Santa Cruz, Calif., July 17-20, 1979, Proceedings (1979)
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    Publication Date: 2011-08-17
    Description: Papers are presented on the following topics: radiation effects in bipolar microcircuits; basic radiation mechanisms in materials and devices; energy deposition and dosimetry; and system responses from SGEMP, IEMP, and EMP. Also considered are basic processes in SGEMP and IEMP, radiation effects in MOS microcircuits, and space radiation effects and spacecraft charging.
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  • 50
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    Noise and loss in balanced and subharmonically pumped mixers. I - Theory. II - Application (1979)
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    Publication Date: 2011-08-17
    Description: The theory of noise and frequency conversion for two-diode balanced and subharmonically pumped mixers is presented. The analysis is based on the equivalent circuit of the Schottky diode, having nonlinear capacitance, series resistance, and shot and thermal noise. Expressions for the conversion loss, noise temperature, and input and output impedances are determined in a form suitable for numerical analysis. In Part II, the application of the theory to practical mixers is demonstrated, and the properties of some two-diode mixers are examined. The subharmonically pumped mixer is found to be much more strongly affected by the loop inductance than the balanced mixer, and the ideal two-diode mixer using exponential diodes has a multiport noise-equivalent network (attenuator) similar to that of the ideal single-diode mixer. It is concluded that the theory can be extended to mixers with more than two diodes and will be useful for their design and analysis, provided a suitable nonlinear analysis is available to determine the diode waveforms.
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  • 51
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    Extension of a theorem used in the investigation of P-N junctions with the scanning electron microscope to arbitrary geometries and arbitrarily inhomogeneous material (1979)
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    Publication Date: 2011-08-17
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Applied Physics Letters; 35; Sept. 1
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  • 52
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    A note on photocurrents in extrinsic semiconductors (1979)
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    Publication Date: 2011-08-17
    Description: The advent of the concept of holes and careful determination of mobilities have made it possible to realize that the potential difference between the contacts of an irradiated semiconductor in the absence of current flow is due to the difference in mobility of electrons and holes. In this paper, a preliminary analysis shows that charge neutrality and zero-current condition are compatible. This situation is clarified and it is found that the equation for the electric field E in the absence of current is not absolutely correct even under low-level injection conditions. In particular, it is shown that fairly large currents can be generated by suitable light sources, currents which are entirely due to the disparity between electron and hole mobilities.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Solid-State Electronics; 22; Mar. 197
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  • 53
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    Comments on measuring the overall and the depressed collector efficiency in TWT's and klystron amplifiers (1979)
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    Publication Date: 2011-08-17
    Description: Kosmahl and Ramins (1977), who reported results achieved with broadband, high-performance TWT's, augmented with multistage depressed collectors for higher overall efficiency, have pointed out the necessity for accurately measuring and correctly defining the various power terms involved. In view of the now wide-spread use of depressed collectors and reported results, the definitions of tube and collector efficiency are restated and comments are provided on the sensitivity of these terms to various sources of experimental and definitional errors in order to permit a uniform evaluation of collector performance.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Electron Devices; ED-26; Feb. 197
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  • 54
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    On the determination of diffusion lengths by means of angle-lapped p-n junctions (1979)
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    Publication Date: 2011-08-17
    Description: A standard procedure for determining the minority carrier diffusion length by means of SEM consists of scanning an angle-lapped surface of a p-n junction and measuring the resulting short circuit current as a function of beam position. The present paper points out that the usual expression linking the short circuit current induced by the electron beam to the angle between the semiconductor surface and the junction plane is incorrect. The correct expression is discussed and it is noted that, for angles less than 10 deg, the new and the old expression are practically indistinguishable.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Solid-State Electronics; 22; Jan. 197
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  • 55
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    Space Shuttle communications RF switch matrix (1979)
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    Publication Date: 2011-08-17
    Description: The Shuttle Orbiter communications equipment includes phase modulation (PM) and frequency modulation (FM) channels. The PM section has the capability of routing high levels of energy (175 W) from any one of four transmitters to any one of four antennas, mutually exclusive. The FM channel uses a maximum of 15-W power routed from either of two transmitters to one of two antennas, mutually exclusive. The paper describes the design and the theory of a logic-controlled RF switch matrix devised for the purposes cited. Both PM and FM channels are computer-controlled with manual overrides. The logic interface is realized with CMOS logic for low power consumption and high noise immunity. The interior of the switch matrix is maintained at a pressure of 15 psi (90% nitrogen, 10% helium) by an electron beam-welded encapsulation. The computational results confirm the viability of the RF switch matrix concept.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Microwave Journal; 22; Jan. 197
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  • 56
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    Comment on the mechanism of operation of the impregnated tungsten cathode (1979)
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    Publication Date: 2011-08-17
    Description: Recent life-test measurements, over 20,000-30,000 h, on impregnated tungsten cathodes in tubes employing an open-type electron-gun structure, show emission current degradation with time. This is in contrast to those recently published by Rittner on B-type cathodes, run in close-spaced diodes, taken some years ago. These more recent life-test results are consistent with the model suggested by Forman and disputed by Rittner that the barium coverage on an impregnated cathode is less than a monolayer for most of its life and decreases with time.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Journal of Applied Physics; 50; Mar. 197
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  • 57
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    Internal stress and degradation in short-wavelength AlGaAs double-heterojunction devices (1979)
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    Publication Date: 2011-08-17
    Description: Aging tests of incoherently operated zinc-doped double-heterojunction (DH) lasers designed for short-wavelength (0.71-0.72 micron) operation show that the introduction of buffer layers between the substrate and the DH structure leads to a drastic reduction in gradual degradation. This is attributed to a decrease in lattice mismatch stress.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Electronics Letters; 15; June 7
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  • 58
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    Radiation hardened PMOS process with ion implanted threshold adjust (1979)
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    Publication Date: 2011-08-17
    Description: By including specific process modifications the effect of ion implantation on radiation hardness can be minimized and radiation hard ion implanted MOS circuits can be fabricated. The experimental procedure followed was to examine key processing steps (with respect to radiation hardness) on ion-implanted individual PMOS transistors. The individual transistors were evaluated by continuously monitoring the threshold voltage as the transistors were being irradiated. By comparing runs it was possible to deduce what is considered a radiation hard ion implanted process. Tests with a complex LSI PMOS IC processor chip containing over 2000 transistors and resistors were also conducted
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  • 59
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    Interim radio spectrum surveillance station (1979)
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    Publication Date: 2011-08-17
    Description: Radio frequency interference at NASA's deep space stations has become a serious problem. A radio spectrum surveillance capability at these stations is needed to determine the sources of interference so that preventative measures can be taken. The first phase of a program to develop this capability was the development of a low-cost surveillance station now in operation at the Goldstone Space Communication Complex near Barstow, California. This interim surveillance station is described and findings from the use of this equipment are presented.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 99-107
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  • 60
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    Minimizing the RMS surface distortions from gravity loadings of the 34-m HA-DEC antenna for deep space missions (1979)
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    Publication Date: 2011-08-17
    Description: The computer analysis of the 34-m HA-DEC antenna by the IDEAS program provided the rms distortions of the surface panels support points for full gravity loadings in the three directions of the basic coordinate system of the computer model. The rms distortions for the gravity vector not in line with any of the three basic directions were solved and contour plotted starting from three surface panels setting declination angle. By inspections of the plots, it was concluded that the setting or rigging angle of -15 degrees declination minimized the rms distortions for sky coverage of plus or minus 22 declination angles to 10 degrees of ground mask.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 94-98
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  • 61
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    Preliminary report on DSN system performance under local weather effects (1979)
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    Publication Date: 2011-08-17
    Description: Local effects of precipitation are studied, and a simplified working model is developed. Experimental results obtained by simulation are in good agreement with the model, showing that it could be an important contribution to system degradation. If this is confirmed, some suggestions for improvement are presented.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 82-88
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  • 62
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    New X-band antenna feeds for the DSN 64-meter stations (1979)
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    Publication Date: 2011-08-17
    Description: New X-band antenna feed assemblies with dual-polarization capability are being implemented in the DSN 64-meter stations. Together with dual X-band traveling wave masers, they permit the simultaneous reception of right- and left-hand circular polarization from the Voyager spacecraft. The new feed also includes a dual hybrid mode feedhorn which increases the antenna gain by 0.36 dB over the present feedhorn.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 71-74
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  • 63
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    Internal noise of a phase-locked receiver with a loop-controlled synthesizer (1979)
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    Publication Date: 2011-08-17
    Description: A local oscillator design that uses a digitally programmed frequency synthesizer instead of an analog VCO was proposed. The integral of the synthesizer input, the digital phase, is a convenient measure of integrated Doppler. The internal noise of such a receiver was examined. At high carrier margin, the local oscillator phase noise equals that of the Block IV receiver, about 2 deg rms at S-band, whereas the digital phase noise is about 0.5 deg rms.
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    Type: The Deep Space Network; p 41-50
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    A generalization of binary minimum shift keying and staggered quadriphase shift keying modulation (1979)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: A generalized modulation scheme, which includes minimum shift keying (MSK) and staggered quadriphase shift keying (SQPSK) as special cases, is analyzed. The general modulator is realized as a one-input, two-output sequence transducer whose outputs select the carrier signal for each band. This form of the modulator has the practical advantage of not requiring any RF filtering since there is no actual mixing of the carriers with the modulating signals. It is shown that the optimum demodulator (whether hard-decision or soft-decision) always can make its decisions from the received waveform over two bands when the interference is additive white Gaussian noise, thus generalizing a well-known result for hard decision demodulation of MSK and SQPSK signals. The power spectra of MSK and SQPSK signals are derived to isolate the role played by coherency between the modulating signals and the carriers.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 26-40
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  • 65
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    Gyrotron: A high-frequency microwave amplifier (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A proposed microwave amplifier mechanism for future generations of millimeter high power uplinks to spacecraft and planetary radar transmitters is introduced. Basic electron-electromagnetic field interaction theory for RF power gain is explained. The starting point for general analytical methods leading to detailed design results is presented.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Deep Space Network; p 8-12
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  • 66
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    Automatic filament warm-up controller (1979)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: As part of the unattended operations objective of the Deep Space Network deep space stations, this filament controller serves as a step between manual operation of the station and complete computer control. Formerly, the operator was required to devote five to fifteen minutes of his time just to properly warm up the filaments on the klystrons of the high power transmitters. The filament controller reduces the operator's duty to a one-step command and is future-compatible with various forms of computer control.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Deep Space Network; p 132-133
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  • 67
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    Radio frequency carrier arraying for near maximum carrier signal-to-noise ratio improvement (1979)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: Radio frequency arraying of several receiving systems provides signal-to-noise ratio improvement relative to a single receiving system. This report considers radio frequency carrier arraying which provides near maximum signal-to-noise ratio improvement for carrier reception and demodulation.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 99-106
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  • 68
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    Coding for optical channels (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: In a previous paper Pierce considered the problem of optical communication from a novel viewpoint, and concluded that performance will likely be limited by issues of coding complexity rather than by thermal noise. This paper reviews the model proposed by Pierce and presents some results on the analysis and design of codes for this application.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 70-77
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  • 69
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    Submicrosecond comparison of intercontinental clock synchronization by VLBI and the NTS satellite (1979)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: The intercontinental clock synchronization capabilities of Very Long Baseline Interferometry (VLBI) and the Navigation Technology Satellite (NTS) were compared in May 1978 by using both methods to synchronize the cesium clocks at the NASA Deep Space Net complexes at Madrid, Spain, and Goldstone, California. The VLBI experiments used the Wideband VLBI Data Acquisition System. The Navigation Technology Satellites were used with NTS Timing Receivers developed by the Goddard Space Flight Center. The two methods agreed at about the one-half microsecond level. The VLBI system also obtained long-term stability information on the HP5061A004 cesium standards by measuring delta T/T over four 3- to 4-day intervals, obtaining stability estimates of (1 + or - 1)x10 to the -13th power for the combined timing systems.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 64-69
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  • 70
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    Comparison of phase modulation systems (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Comparison of the energy to noise ratio necessary to obtain a given modulation bit error probability has indicated that three-phase modulation is about 0.75 db superior to four-phase. It is shown that this apparent superiority results entirely from the greater bandwidth required by the three-phase system for the same bit transmission rate. Two further comparison criteria are proposed, which are based on the cut-off rate R sub 0 of the discrete channel created by the modulation system. For the criterion which constrains both the bandwidth and transmitted power, it is shown that four-phase modulation is always superior to three-phase modulation. The conclusion is that three-phase modulation offers no practical advantage over four-phase modulation.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 57-63
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  • 71
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    DSN ground communications facility (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A functional description of the Ground Communications Facilities and its relationships with other elements of the Deep Space Network and NASA Communications Network is presented together with development objectives and goals and comments on implementation activities in support of flight projects.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 19-28
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  • 72
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    DSN command system Mark 3-78 (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The Deep Space Network Command System Mark III-78 implementation and functional operation are described. Software upgrade enables expanded storage capacity in the Deep Space Station Command Processor Assembly. Store-and-forward command data handling is operational for Voyager and Helios. Near-real-time command data handling was retained for Viking and Pioneer.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 11-18
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  • 73
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    The NASA radar entomology program at Wallops Flight Center (1979)
    In:  Other Sources
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    Publication Date: 2016-06-07
    Description: NASA contribution to radar entomology is presented. Wallops Flight Center is described in terms of its radar systems. Radar tracking of birds and insects was recorded from helicopters for airspeed and vertical speed.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Radar, Insect Population Ecology, and Pest Management; p 161-169
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  • 74
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    Quantitative Analysis of Radar Returns from Insects (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: When a number of flying insects is low enough to permit their resolution as individual radar targets, quantitative estimates of their aerial density are developed. Accurate measurements of heading distribution using a rotating polarization radar to enhance the wingbeat frequency method of identification are presented.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA. Wallops Flight Center Radar, Insect Population Ecology, and Pest Management; p 131-158
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  • 75
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    Radar program at Western Cotton Research Laboratory (1979)
    In:  Other Sources
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    Publication Date: 2016-06-07
    Description: An entomological radar similar to those used in England is developed. The radar will detect insects in flight and the data will be used for studying insect dispersal.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA. Wallops Flight Center Radar, Insect Population Ecology, and Pest Management; p 159-160
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  • 76
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    Radar observation of known and unknown clear echoes (1979)
    In:  Other Sources
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    Publication Date: 2016-06-07
    Description: Target cross-section as a function of wavelength for known insects, known bird, and dot targets is presented. Tracking data using the time series analysis was tabulated for known birds. Examples were selected from these early works to give entomologists some indication of the types of information that are available by radar as well as examples of the different sources of clear-air radar backscatter.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA. Wallops Flight Center Radar, Insect Population Ecology, and Pest Management; p 113-130
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  • 77
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    Theoretical modelling and experimental data matching for active and passive microwave remote sensing of Earth terrain (1979)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: Two theoretical models were developed to characterize terrain media: a random medium with a variance, a horizontal correlation length; and a homogeneous dielectric containing discrete scatterers. The earth terrain is modelled as layers of such scattering media bounded by air above and half-space below. Matching the theoretical results with experimental data collected from vegetation and snow-ice fields shows that: (1) for observation angles near nadir, rough surface effects are important; (2) for snow-ice field the horizontal correlation length is greater than the vertical correlation length whereas for vegetation field their relative sizes depend on the types of vegetation; (3) the vertically polarized backscattering cross-section is always larger than the horizontally polarized backscattering cross-section for half-space scattering media; (4) for snow field displaying diurnal change, a three-layer model including a thin top layer caused by sunlight illumination must be used; and (5) for a random medium with equal horizontal and vertical correlation lengths, the measured data can also be matched with a corresponding discrete scatterer model.
    Keywords: COMMUNICATIONS AND RADAR
    Type: AGARD Terrain Profiles and Contours in Electromagnetic Wave Propagation; 8 p
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  • 78
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    Satellite-aided mobile radio concepts study: Concept definition of a satellite-aided mobile and personal radio communication system (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The satellite system requires the use of a large satellite antenna and spacecraft array power of about 12 kW or more depending on the operating frequency. Technology developments needed include large offset reflector multibeam antennas, satellite electrical power sybsystems providing greater than 12 kW of power, signal switching hardware, and linearized efficient solid state amplifiers for the satellite-aided mobile band. Presently there is no frequency assignment for this service, and it is recommended that an allocation be pursued. The satellite system appears to be within reasonable extrapolation of the state of the art. It is further recommended that the satellite-aided system spacecraft definition studies and supporting technology development be initiated.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-166646
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  • 79
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    Development program on a cold cathode electron gun (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A prototype electron gun with a field emitter cathode capable of producing 95 mA in a 1/4 mm diameter beam at 12 kV was produced. Achievement of this goal required supporting studies in cathode fabrication, cathode performance, gun design, cathode mounting and gun fabrication. A series of empirical investigations advanced fabrication technology: More stable emitters were produced and multiple cone failure caused by chain reaction discharges were reduced. The cathode is capable of producing well over 95 mA, but a substantial collector development effort was required to demonstrate emission levels in the 100 mA region. Space charge problems made these levels difficult to achieve. Recommendations are made for future process and materials investigation. Electron gun designs were modeled and tested. A pair of two-electrode gun structures were fabricated and tested; one gun was delivered to NASA. Cathodes were pretested up to 100 mA at SRI and delivered to NASA for test in the gun structure.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-159570 , SRI-5413
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  • 80
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    A preliminary study of a very large space radiometric antenna (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An approach used to compute the size of a special radiometric reflector antenna is presented. Operating at 1 GHz, this reflector is required to produce 200 simultaneous contiguous beams, each with a 3 dB footprint of 1 km from an assumed satellite height of 650 km. The overall beam efficiency for each beam is required to be more than 90%.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-TM-80047
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  • 81
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    The 2.2 GHz Surface Acoustic Wave (SAW) oscillator development Ku-band frequency source development (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Two 2.2 GHz SAW oscillators using aluminum nitride on sapphire (AlN/Al2O3) delay lines were fabricated. The oscillators were electronically temperature compensated and characterized. One of the oscillators was used as the frequency reference for the Ku band source; the second oscillator is available for continued evaluation. A 15 GHz frequency source was designed and fabricated. The 15 GHz source consists of a Ku band FET oscillator which is phase locked to the frequency multiplied (X7) output of the 2.2 GHz SAW reference source. The Ku band source was built using microstrip circuit designs, which are hybrid compatible. Two wafer runs of 2.2 GHz TED devices were fabricated and evaluated. The devices were mounted on microstrip test substrates and evaluated as 15 GHz divide by 7 circuits. The device evaluation indicated that in their present form the TED is not a practical circuit element.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-160080
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  • 82
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    Standard Transistor Array (STAR). Volume 2, addendum 1: SIMLOG/TESTGN user's guide (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A brief introduction to the SIMLOG/TESTGN system of programs is given. Detailed instructions on how to use the system are also included. SIMLOG is a logic simulation program. TESTGN is a test pattern generation program.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-161295
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  • 83
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    Standard Transistor Array (STAR). Volume 2: Test pattern generation (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Testing of large scale integrated logic circuits is considered from the point-of-view of automatic test pattern generation. A logic simulator based approach for automatic test pattern generation is taken and is described. The logic model and the timing model used in the simulator are also described. Two methods are presented for generating test patterns from the output of the simulator. Recommendations for future study are also presented.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-161294
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  • 84
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    Standard Transistor Array (STAR). Volume 1, addendum 2: CAPSTAR programmer's guide (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Instructions are given for updating and maintaining the cell arrangement program for the standard transistor array (CAPSTAR).
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-161292
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  • 85
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    Standard Transistor Array (STAR). Volume 1, addendum 1: CAPSTAR user's guide (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The cell placement techniques developed for use with the standard transistor array were incorporated in the cell arrangement program for STAR (CAPSTAR). Instructions for use of this program are given.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-161291
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  • 86
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    Standard Transistor Array (STAR). Volume 1: Placement technique (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A large scale integration (LSI) technology, the standard transistor array uses a prefabricated understructure of transistors and a comprehensive library of digital logic cells to allow efficient fabrication of semicustom digital LSI circuits. The cell placement technique for this technology involves formation of a one dimensional cell layout and "folding" of the one dimensional placement onto the chip. It was found that, by use of various folding methods, high quality chip layouts can be achieved. Methods developed to measure of the "goodness" of the generated placements include efficient means for estimating channel usage requirements and for via counting. The placement and rating techniques were incorporated into a placement program (CAPSTAR). By means of repetitive use of the folding methods and simple placement improvement strategies, this program provides near optimum placements in a reasonable amount of time. The program was tested on several typical LSI circuits to provide performance comparisons both with respect to input parameters and with respect to the performance of other placement techniques. The results of this testing indicate that near optimum placements can be achieved by use of the procedures incurring severe time penalties.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-161289
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  • 87
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    The MSFC complementary metal oxide semiconductor (including multilevel interconnect metallization) process handbook (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The fabrication techniques for creation of complementary metal oxide semiconductor integrated circuits at George C. Marshall Space Flight Center are described. Examples of C-MOS integrated circuits manufactured at MSFC are presented with functional descriptions of each. Typical electrical characteristics of both p-channel metal oxide semiconductor and n-channel metal oxide semiconductor discrete devices under given conditions are provided. Procedures design, mask making, packaging, and testing are included.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-TM-78188 , M-262
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  • 88
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    Thermally grown oxide and diffusions for automatic processing of integrated circuits (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A totally automated facility for semiconductor oxidation and diffusion was developed using a state-of-the-art diffusion furnace and high temperature grown oxides. Major innovations include: (1) a process controller specifically for semiconductor processing; (2) an automatic loading system to accept wafers from an air track, insert them into a quartz carrier and then place the carrier on a paddle for insertion into the furnace; (3) automatic unloading of the wafers back onto the air track, and (4) boron diffusion using diborane with plus or minus 5 percent uniformity. Processes demonstrated include Wet and dry oxidation for general use and for gate oxide, boron diffusion, phosphorous diffusion, and sintering.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-TM-78247
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  • 89
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    NASA electronic message experiment and study: Detailed test plans (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A methodology for evaluating the utility of high speed digital facsimile as a component of the projected NASA-wide electronic message network is presented. Equipment checkout, operator familiarization, pretest calibration, and the development of procedures are addressed. An experimental test program of the facsimile message service which will carry duplicates of the actual messages sent by other means is highlighted. Also, an operational test program during which messages will be sent on a regular basis in order to accumulate the information that will be used to evaluate system performance and project future growth is described.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-160007
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  • 90
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    Interleaving device (1979)
    In:  CASI
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    Publication Date: 2019-06-28
    Description: An interleaving device for processing energy signals between various logic devices has a first number of spaced energy carrying layer mateials. Each of the first layer materials has a number of juxtaposed conduits passing energy signals through which are passed. Each of the conduits has a longitudinal axis substantially parallel to a diagonal of each of the first layers. A second group of energy carrying materials is arranged between adjacent ones of the spaced first layer materials. Each of the second layer materials has a number of juxtaposed conduits through which the energy signals are also passed. Each of the conduits in the second layer has a longitudinal axis substantially parallel to a diagonal of each of the second layer materials and substantially perpendicular to the axes of the conduits of the first layer materials.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
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  • 91
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    A tactile-output paging communication system for the deaf-blind (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A radio frequency paging communication system that has coded vibrotactile outputs suitable for use by deaf-blind people was developed. In concept, the system consists of a base station transmitting and receiving unit and many on-body transmitting and receiving units. The completed system has seven operating modes: fire alarm; time signal; repeated single character Morse code; manual Morse code; emergency aid request; operational status test; and message acknowledge. The on-body units can be addressed in three ways: all units; a group of units; or an individual unit. All the functions developed were integrated into a single package that can be worn on the user's wrist. The control portion of the on-body unit is implemented by a microcomputer. The microcomputer is packaged in a custom-designed hybrid circuit to reduce its physical size.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-152332
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  • 92
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    A 4-W 56-dB gain microstrip amplifier at 15 GHz utilizing GaAs FET's and IMPATT diodes (1979)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Performance results and design considerations are presented for an all solid-state Ku-band power amplifier which is feasible for use in PM communication systems for airborne or spacecraft transmitter applications. A six-stage GaAs FET preamplifier and a driver and balanced power amplifier utilizing GaAs IMPATT diodes operating in the injection locked oscillator mode are discussed. For high power and efficiency Schottky-Read IMPATT's with low-high-low doping profiles are employed. For improved reliability the IMPATT's incorporate a TiW barrier metallization to retard degradation of the IMPATT's. Results of accelerated life testing of the IMPATT devices are also presented.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
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  • 93
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    Design of a 24-channel transmultiplexer (1979)
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    Publication Date: 2019-06-27
    Description: The design of a transmultiplexer capable of performing the bilateral conversion between one 1544 kbit/s digital signal (which represents 24 PCM coded voice channels) and two analog group signals (each one containing 12 voice channels in the 60-108 kHz band) is investigated. It is shown that an FIR filter bank required as part of such a transmultiplexer can be realized efficiently by cascading a discrete cosine transform processor and a weighting network. Fast convolution algorithms are derived for evaluating the cosine transform. A method of using the symmetry conditions to reduce the computation rate in the weighting network and an elegant hardware configuration for implementing it are also discussed.
    Keywords: COMMUNICATIONS AND RADAR
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  • 94
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    Prediction of field-time-dependent gate-oxide breakdown in MOS devices (1979)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The model for field-time-dependent breakdown in the gate oxide of MOS devices is extended and verified with experimental data. The model permits accelerated tests at high fields which can be used to predict gate-oxide breakdowns at much longer times at normal operating fields.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Solid-State Electronics; 22; Nov. 197
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  • 95
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    Space applications of superconductivity - High field magnets (1979)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The paper discusses developments in superconducting magnets and their applications in space technology. Superconducting magnets are characterized by high fields (to 15T and higher) and high current densities combined with low mass and small size. The superconducting materials and coil design are being improved and new high-strength composites are being used for magnet structural components. Such problems as maintaining low cooling temperatures (near 4 K) for long periods of time and degradation of existing high-field superconductors at low strain levels can be remedied by research and engineering. Some of the proposed space applications of superconducting magnets include: cosmic ray analysis with magnetic spectrometers, energy storage and conversion, energy generation by magnetohydrodynamic and thermonuclear fusion techniques, and propulsion. Several operational superconducting magnet systems are detailed.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Cryogenics; 19; Dec. 197
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  • 96
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    Distributed effect in GaAs MESFET (1979)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: In order to obtain higher output power, the width of a single cell MESFET must be large. When it becomes too large the distributed effect along the width direction tends to limit the output power. It is found that the distributed effect is important when the gate width not less than 150 microns and that the gain decreases with gate width. Also found is that spurious oscillations occur due to line resonances at much higher frequencies than can be accounted for by the instability factor in the discrete device model.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Solid-State Electronics; 22; Dec. 197
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  • 97
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    Cosmic ray-induced soft errors in static MOS memory cells (1979)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Previous analytical models were extended to predict cosmic ray-induced soft error rates in static MOS memory devices. The effect is due to ionization and can be introduced by high energy, heavy ion components of the galactic environment. The results indicate that the sensitivity of memory cells is directly related to the density of the particular MOS technology which determines the node capacitance values. Hence, CMOS is less sensitive than e.g., PMOS. In addition, static MOS memory cells are less sensitive than dynamic ones due to differences in the mechanisms of storing bits. The flip-flop of a static cell is inherently stable against cosmic ray-induced bit flips. Predicted error rates on a CMOS RAM and a PMOS shift register are in general agreement with previous spacecraft flight data.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
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  • 98
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    Simulation of cosmic-ray induced soft errors and latchup in integrated-circuit computer memories (1979)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Soft errors have been induced in solid-state static RAM's by iron nuclei from the Lawrence Berkeley Laboratory (LBL) Bevalac, in experiments designed to prove the ability of iron-group cosmic rays to generate such errors. Subsequently, various delidded device types were tested in beams of argon and krypton ions from the LBL 88-inch Cyclotron, at energies near 2 MeV/nucleon. The latter tests showed that some devices are essentially immune to bit error while others are quite susceptible. Good agreement was obtained with model predictions in cases where the latter exist. Latchup, whose cause is attributed to individual heavy ions, was also observed in some device types.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
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  • 99
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    On the limitations of the concept of space frequency equivalence (1979)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: A narrow-band correlation interferometer using directive (large) antennas is equivalent to a wideband correlation interferometer employing isotropic (small) antennas. This concept of space frequency equivalence, due to Kock and Stone, is reexamined and is shown to hold exactly only for the mean or expected values of the correlation interferometer outputs. If their variances are considered, the equivalence disappears, with the variance fo the wideband system always equal to or greater than that of the narrow-band system.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Radio Science; 14; Nov
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  • 100
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    Crosstalk cancellation on linearly and circularly polarized communications satellite links (1979)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The paper discusses the cancellation network approach for reducing crosstalk caused by depolarization on a dual-polarized communications satellite link. If the characteristics of rain depolarization are sufficiently well known, the cancellation network can be designed in a way that reduces system complexity, the most important parameter being the phase of the cross-polarized signal. Relevant theoretical calculations and experimental data are presented. The simplicity of the cancellation system proposed makes it ideal for use with small domestic or private earth terminals.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Radio Science; 14; Nov
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