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  • Other Sources  (387)
  • ELECTRONICS AND ELECTRICAL ENGINEERING  (387)
  • 1985-1989  (387)
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  • 1988  (188)
  • 1987  (199)
  • 1
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    Modal identification using single-mode projection filters and comparison with ERA and MLE results (1988)
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    Publication Date: 2011-08-24
    Description: The Single-Mode Projection Filter (SPF) is a newly developed algorithm for eigensystem parameter identification from both analytical results and test data. The SPF is formulated with a single mode only and practical for parallel processing implementation. Explicit formulations of SPF are derived for the multi-input multi-output (MIMO) system by using the orthogonal matrices of the controllability and observability matrices in the general sense. The modal parameters of SPF are initially obtained from an analytical model in modal space. The experimental data are then processed through SPF to update its modal parameters and to minimize a cost function defined by the norm of an error matrix. The updated modal parameters represent the characteristics of the test data. A two-dimensional global minimum optimization algorithm is developed and applied for the filter update by using the interval analysis method. The SPF is developed based on a single-mode subsystem and identifies only one modal frequency and one modal damping within a specified region. For an n-modes structure, n SPF can be implemented for parallel processing to reduce the computational burden. The SPF is applied to analyze the simulated data for the MAST beam structure. The estimated modal parameters are comparable to those from the Eigensystem Realization Algorithm (ERA) and repeated modal frequencies are identified. The modal analysis of the Spacecraft Control Laboratory Experiment (SCOLE) data is also performed by using the ERA and the Maximum Likelihood Estimate (MLE). The result shows that the first five modal frequencies are very close from ERA and MLE. However, there are slight disparities in the damping rates and the computational burdens are quite different among these two algorithms.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: JPL, Model Determination for Large Space Systems Workshop, Volume 2; p 509-523
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  • 2
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    p/n InP homojunction solar cells with a modified contacting scheme by liquid phase epitaxy (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: p/n InP homojunction solar cells with a modified contacting scheme have been fabricated from wafers grown by liquid phase epitaxy. A p(+)-In(0.53)Ga(0.47)As contacting layer is incorporated in the cell structure to reduce contact resistance and to eliminaate surface spiking problems at the front surface. The highest conversion efficiency (total area) obtained under AM0 illumination is 15.0 percent. The corresponding open-circuit voltage, short-circuit current density, and fill factor for the best cell are 0.866 V, 29.3 mA/sq cm, and 81.0 percent, respectively.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Journal of Applied Physics (ISSN 0021-8979); 63; 1198-120
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  • 3
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    Tunneling effects in the current-voltage characteristics of high-efficiency GaAs solar cells (1988)
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    Publication Date: 2011-08-19
    Description: Evidence is that tunneling via states in the forbidden gap is the dominant source of excess current in the dark current-voltage (I-V) characteristics of high-efficiency DMCVD grown Al(x)Ga(1-x)As/GaAs(x is equal to or greater than 0.85) solar cells. The dark forward and reverse I-V measurements were made on several solar cells, for the first time, at temperatures between 193 and 301 K. Low-voltage reverse-bias I-V data of a number of cells give a thermal activation energy for excess current of 0.026 + or - 0.005 eV, which corresponds to the carbon impurity in GaAs. However, other energy levels between 0.02 eV and 0.04 eV were observed in some cells which may correspond to impurity levels introduced by Cu, Si, Ge, or Cd. The forward-bias excess current is mainly due to carrier tunneling between localized levels created in the space-charge layer by impurities such as carbon, which are incorporated during the solar cell growth process. A model is suggested to explain the results.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Solid-State Electronics (ISSN 0038-1101); 31; 2, 19
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  • 4
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    Models of second-order effects in metal-oxide-semiconductor field-effect transistors for computer applications (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Second-order effects in metal-oxide-semiconductor field-effect transistors (MOSFETs) are important for devices with dimensions of 2 microns or less. The short and narrow channel effects and drain-induced barrier lowering primarily affect threshold voltage, but formulas for drain current must also take these effects into account. In addition, the drain current is sensitive to channel length modulation due to pinch-off or velocity saturation and is diminished by electron mobility degradation due to normal and lateral electric fields in the channel. A model of a MOSFET including these considerations and emphasizing charge conservation is discussed.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Journal of Applied Physics (ISSN 0021-8979); 63; 5131-514
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  • 5
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    Slotline fed microstrip antenna array modules (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A feed network comprised of a combination of coplanar waveguide and slot transmission line is described for use in an array module of four microstrip elements. Examples of the module incorporating such networks are presented as well as experimentally obtained impedance and radiation characteristics.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Microwave and Optical Technology Letters (ISSN 0895-2477); 1; 26-29
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  • 6
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    Secondary ion mass spectrometry study of ex situ annealing of epitaxial GaAs grown on Si substrates (1988)
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    Publication Date: 2011-08-19
    Description: Samples of epitaxial GaAs grown on (100) Si substrates using molecular beam epitaxy were annealed at four different temperatures, from 800 to 950 C. Following annealing, the samples were analyzed using secondary ion mass spectrometry. Depth profiles of Ga, As, and Si reveal optimum conditions for annealing, and place a lower limit on a damage threshold for GaAs/Si substrates.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Applied Physics Letters (ISSN 0003-6951); 52; 731
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  • 7
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    Multijunction upper subcell cascade photovoltaics for space applications (1988)
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    Publication Date: 2011-08-19
    Description: A new class of cascade high-efficiency photovoltaics designed for space-based applications is proposed. The design improves upper subcell performance and avoids electrical and optical losses associated with an intercell ohmic contact. Multijunction upper subcells reduce bulk recombination of photogenerated minority carriers by decreasing the average collection distance, yielding improved spectral response and radiation tolerance. A three-terminal design is employed which circumvents the need for a monolithic intercell contact and, thus, the losses associated with such a contact. Problems related to array interconnection of three-terminal devices may be solved by creating a two-terminal cell from complementary pairs (n-p-n and p-n-p) of three-terminal cells. Simulations of lattice-matched AlGaAs-GaAs and lattice-mismatched AlGaAs-InGaAs cascade cells show that one-sun AM0 efficiencies in excess of 26 and 28 percent, respectively, are possible.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Journal of Applied Physics (ISSN 0021-8979); 63; 540-546
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  • 8
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    Measurement circuits for silicon-diode and solar-cell lifetime and surface recombination velocity by electrical short-circuit current delay (1988)
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    Publication Date: 2011-08-19
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Electron Devices (ISSN 0018-9383); ED-35; 85-88
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  • 9
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    Finite-state codes (1988)
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    Publication Date: 2011-08-19
    Description: A class of codes called finite-state (FS) codes is defined and investigated. The codes, which generalize both block and convolutional codes, are defined by their encoders, which are finite-state machines with parallel inputs and outputs. A family of upper bounds on the free distance of a given FS code is derived. A general construction for FS codes is given, and it is shown that in many cases the FS codes constructed in this way have a free distance that is the largest possible. Catastrophic error propagation (CEP) for FS codes is also discussed. It is found that to avoid CEP one must solve the graph-theoretic problem of finding a uniquely decodable edge labeling of the state diagram.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Information Theory (ISSN 0018-9448); 34; 1083-108
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  • 10
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    Monolithic watt-level millimeter-wave diode-grid frequency tripler array (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: In order to provide watt-level CW output power throughout the millimeter and submillimeter wave region, thousands of solid-state diodes have been monolithically integrated using a metal grid to produce a highly efficient frequency multiplier. Devices considered include GaAs Schottky diodes, thin MOS diodes, and GaAs Barrier-Intrinsic-N(+)diodes. The performance of the present compact low-cost device has been theoretically and experimentally validated.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: International Journal of Infrared and Millimeter Waves (ISSN 0195-9271); 9; 1011-102
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  • 11
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    Lateral charge transport from heavy-ion tracks in integrated circuit chips (1988)
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    Publication Date: 2011-08-19
    Description: A 256K DRAM has been used to study the lateral transport of charge (electron-hole pairs) induced by direct ionization from heavy-ion tracks in an IC. The qualitative charge transport has been simulated using a two-dimensional numerical code in cylindrical coordinates. The experimental bit-map data clearly show the manifestation of lateral charge transport in the creation of adjacent multiple-bit errors from a single heavy-ion track. The heavy-ion data further demonstrate the occurrence of multiple-bit errors from single ion tracks with sufficient stopping power. The qualitative numerical simulation results suggest that electric-field-funnel-aided (drift) collection accounts for single error generated by an ion passing through a charge-collecting junction, while multiple errors from a single ion track are due to lateral diffusion of ion-generated charge.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); 35; 1644-164
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  • 12
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    Investigation of single-event upset (SEU) in an advanced bipolar process (1988)
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    Publication Date: 2011-08-19
    Description: An extensive analytical and experimental study SEU in an advanced silicon bipolar process was made. The modeling used process and device parameters to model the SEU charge, collection, and circuit response derived from a special version of PISCES in cylindrical coordinates and SPICE, respectively. Data are reported for test cells of various sizes.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); 35; 1573-157
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  • 13
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    A CMOS matrix for extracting MOSFET parameters before and after irradiation (1988)
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    Publication Date: 2011-08-19
    Description: An addressable matrix of 16 n- and 16 p-MOSFETs was designed to extract the dc MOSFET parameters for all dc gate bias conditions before and after irradiation. The matrix contains four sets of MOSFETs, each with four different geometries that can be biased independently. Thus the worst-case bias scenarios can be determined. The MOSFET matrix was fabricated at a silicon foundry using a radiation-soft CMOS p-well LOCOS process. Co-60 irradiation results for the n-MOSFETs showed a threshold-voltage shift of -3 mV/krad(Si), whereas the p-MOSFETs showed a shift of 21 mV/krad(Si). The worst-case threshold-voltage shift occurred for the n-MOSFETs, with a gate bias of 5 V during the anneal. For the p-MOSFETs, biasing did not affect the shift in the threshold voltage. A parasitic MOSFET dominated the leakage of the n-MOSFET biased with 5 V on the gate during irradiation. Co-60 test results for other parameters are also presented.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); 35; 1529-153
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  • 14
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    Comparison of the degradation effects of heavy ion, electron, and cobalt-60 irradiation in an advanced bipolar process (1988)
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    Publication Date: 2011-08-19
    Description: Experimental measurements are reported of the degradation effects of high-energy particles (heavy Br ions and electrons) and Co-60 gamma-rays on the current gain of minimum-geometry bipolar transistors made from an advanced process. The data clearly illustrate the total-ionizing-dose vs particle-fluence behavior of this bipolar transistor produced by an advanced process. In particular, bulk damage from Co-60 gamma rays in bipolar transistors (base transport factor degradation) and surface damage in bipolar transistors from ionizing radiation (emitter-efficiency degradation) have been observed. The true equivalence between various types of radiation for this process technology has been determined on the basis of damage from the log K1 intercepts.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); 35; 1428-143
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  • 15
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    Experience, problems, and subtleties of electrostatic discharge at JPL (1988)
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    Publication Date: 2011-08-19
    Description: Approaches used to control electrostatic discharge (ESD) at the JPL are discussed. ESD control problems generally occur in the following: (1) wrist straps; (2) outer garments that preclude the generation of static charge; and (3) materials, items, techniques, or processes permitting the development of a static charge. Consideration is given to the cleaning of antistatic materials, outside contracts, vapor degreasing, and electrostatically charged electrical cables.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Journal of Environmental Sciences (ISSN 0022-0906); 31; 42-46
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  • 16
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    An electrostatically and a magnetically confined electron gun lens system (1988)
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    Publication Date: 2011-08-19
    Description: Focal properties, electron trajectory calculations, and geometries are given for two electron 'gun' lens systems that have a variety of applications in, for example, electron-neutral and electron-ion scattering experiments. One nine-lens system utilizes only electrostatic confinement and is capable of focusing electrons onto a fixed target with extremely small divergence angles, over a range of final energies 1-790 eV. The second gun lens system is a simpler three-lens system suitable for use in a uniform, solenoidal magnetic field. While the focusing properties of such a magnetically confined lens systenm are simpler to deal with, the system does illustrate features of electron extraction and Brillouin flow that have not been suitably emphasized in the literature.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Review of Scientific Instruments (ISSN 0034-6748); 59; 2418-242
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  • 17
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    An exact, closed-form expression of the integral chord-length distribution for the calculation of single-event upsets induced by cosmic rays (1988)
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    Publication Date: 2011-08-19
    Description: This paper presents a derivation of an exact closed-form expression of the integral chord-length distribution for the calculation of single-event upsets (SEUs) in an electronic memory cell, caused by cosmic rays. Results computed for two rectangular parallelepipeds using this exact expression are compared with those computed with Bradford's (1979) semiexact expression of C(x). It is found that the values of C(x) are identical for x equal or smaller than b but are vastly different for x greater than b. Moreover, while C(x) of Bradford gives reasonably accurate values of SEU rate for certain sets of computational parameters, it gives values more than 10 times larger than the correct values for other sets of parameters.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Journal of Applied Physics (ISSN 0021-8979); 64; 5132-513
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  • 18
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    Advances in the development of piezoelectric quartz-crystal oscillators, hydrogen masers, and superconducting frequency standards (1988)
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    Publication Date: 2011-08-19
    Description: This paper describes recent research advances made in the development of radiation-hardened piezoelectric quartz oscillators, hydrogen masers, and superconducting oscillators, with emphasis placed on the principles involved in the operation of these oscillators and the factors affecting the operation. Particular attention is given to the radiation-susceptibility studies of quartz-crystal resonators, the hydrogen-maser relaxation process and noise sources, and low-phase-noise superconducting oscillators. Diagrams of these devices and performance graphs are included.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Johns Hopkins APL Technical Digest (ISSN 0270-5214); 9; 212-220
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  • 19
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    Contact regrowth technique for low-resistance nonalloyed contacts to the hot-electron transistor (1988)
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    Publication Date: 2011-08-19
    Description: A novel contact regrowth technique for the formation of extremely low nonalloyed ohmic contacts is reported. The successful demonstration of this technique is reported on an InGaAs/InAlAs hot-electron transistor device. For the investigated InGaAs-based structure, the regrown contacting scheme reported includes an In(0.53)Ga(0.47)As layer, an InAs/GaAs strained-layer superlattice, and an InAs cap, all heavily doped n type with Si. A very low specific contact resistance of 1.8 x 10 to the -7th ohm sq cm to the base layer is obtained. The higher current densities achieved in the transistor characteristics are in close agreement with calculations, and a contact model is presented explaining the poor results of conventional nonalloyed contacts.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Applied Physics Letters (ISSN 0003-6951); 53; 1738-174
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  • 20
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    A new tunable solid-state laser (1988)
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    Publication Date: 2011-08-19
    Description: A tunable solid state laser system, chromium-activated forsterite (Cr3+: Mg2SiO4), which has the potential for tunability from 850-1400 nm, is introduced. The characteristics of the host crystal are examined. Laser experiments and measurements are presented, including the observation of pulsed laser action at room temperature. The possibilities of the system are also considered.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Photonics Spectra (ISSN 0731-1230); 95-97
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  • 21
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    On the VLSI design of a pipeline Reed-Solomon decoder using systolic arrays (1988)
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    Publication Date: 2011-08-19
    Description: A new very large scale integration (VLSI) design of a pipeline Reed-Solomon decoder is presented. The transform decoding technique used in a previous article is replaced by a time domain algorithm through a detailed comparison of their VLSI implementations. A new architecture that implements the time domain algorithm permits efficient pipeline processing with reduced circuitry. Erasure correction capability is also incorporated with little additional complexity. By using multiplexing technique, a new implementation of Euclid's algorithm maintains the throughput rate with less circuitry. Such improvements result in both enhanced capability and significant reduction in silicon area.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Computers (ISSN 0018-9340); 37; 1273-128
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  • 22
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    Sulfur as a surface passivation for InP (1988)
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    Publication Date: 2011-08-19
    Description: The use of liquid and gas phase sulfur pretreatment of the surface of InP as a way to form a near-ideal passivated surface prior to chemical vapor deposition of SiO2 was investigated. Results of high-frequency and quasi-static capacitance-voltage measurements, as well as enhancement mode insulated gate field-effect transistor (FET) transductance and drain current stability studies, all support the efficacy of this approach for metal-insulator-semiconductor application of this semiconductor. In particular, surface state values in the range of 10 to the 10th to a few 10 to the 11th/sq cm per eV and enhancement mode FET drain current drifts of less than 5 percent over a 12 h test period were measured.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Applied Physics Letters (ISSN 0003-6951); 53; 134-136
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  • 23
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    Tunable superlattice p-i-n photodetectors: Characteristics, theory, and applications (1988)
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    Publication Date: 2011-08-19
    Description: Extended measurements and theory on the recently developed monolithic wavelength demultiplexer consisting of voltage-tunable superlattice p-i-n photodetectors in a waveguide configuration are discussed. It is shown that the device is able to demultiplex and detect two optical signals with a wavelength separation of 20 nm directly into different electrical channels at a data rate of 1 Gb/s and with a crosstalk attenuation varying between 20 and 28 dB, depending on the polarization. The minimum acceptable crosstalk attenuation at a data rate of 100 Mb/s is determined to be 10 dB. The feasibility of using the device as a polarization angle sensor for linearly polarized light is also demonstrated. A theory for the emission of photogenerated carriers out of the quantum wells is included, since this is potentially a speed limiting mechanism in these detectors. It is shown that a theory of thermally assisted tunneling by polar optical phonon interaction is able to predict emission times consistent with the observed temporal response.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Journal of Quantum Electronics (ISSN 0018-9197); 24; 787-801
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  • 24
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    Characteristics of broadside coupled cylindrical striplines (1988)
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    Publication Date: 2011-08-19
    Description: This letter presents a method for calculating the even and odd mode impedances of broadside coupled cylindrical stiplines using the conformal mapping technique. Closed form expressions are presented for calculating the even and odd mode characteristic impedances. The data for even and odd mode impedances are presented. The analysis can also be extended to warped broadside coupled striplines.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Microwave and Optical Technology Letters (ISSN 0895-2477); 1; 133-136
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  • 25
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    Simulation of proton-induced energy deposition in integrated circuits (1988)
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    Publication Date: 2011-08-19
    Description: A time-efficient simulation technique was developed for modeling the energy deposition by incident protons in modern integrated circuits. To avoid the excessive computer time required by many proton-effects simulators, a stochastic method was chosen to model the various physical effects responsible for energy deposition by incident protons. Using probability density functions to describe the nuclear reactions responsible for most proton-induced memory upsets, the simulator determines the probability of a proton hit depositing the energy necessary for circuit destabilization. This factor is combined with various circuit parameters to determine the expected error-rate in a given proton environment. An analysis of transient or dose-rate effects is also performed. A comparison to experimental energy-disposition data proves the simulator to be quite accurate for predicting the expected number of events in certain integrated circuits.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); 35; 981-986
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  • 26
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    Barrier height enhancement of InP-based n-Ga(0.47)In(0.53)As Schottky-barrier diodes grown by molecular beam epitaxy (1988)
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    Publication Date: 2011-08-19
    Description: Barrier height enhancement of an InP-based p(+)n-Ga(0.47)In(0.53)As Schottky diode grown by MBE has been demonstrated for infra-red photodetector applications. A barrier height of 0.35 eV for n-Ga(0.47)In(0.53)As Schottky barrier diodes, was increased to the effective barrier height of 0.55 eV, with a p(+)-Ga(0.47)In(0.53)As surface layer of 30 nm thick. The results show a reverse leakage current density of 0.0015 A/sq cm and a junction capacitance of 0.3 pF, which are comparable to those of p-Ga(0.47)In(0.53)As Schottky-barrier diodes at a reverse bias voltage of 5 V.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Electronics Letters (ISSN 0013-5194); 24; 687-689
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  • 27
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    Al(0.3)Ga(0.7)As / Al(0.05)Ga(0.95)As light-emitting diodes on GaAs-coated Si substrates grown by liquid phase epitaxy (1988)
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    Publication Date: 2011-08-19
    Description: Al(0.3)Ga(0.7)As/Al(0.05)Ga(0.95)As double-heterostructure light-emitting diodes (LEDs) were successfully grown for the first time by liquid phase epitaxy on a GaAs-coated Si substrate that was prepared by a sequential process of migration-enhanced epitaxy and molecular beam epitaxy. The edge-emitting LEDs had diode ideality factors of 1.54 at a forward-biased voltage higher than 0.9 V and external quantum efficiencies of 0.0033 W/A per facet. This efficiency is 50 times higher than the previously reported value, and is on the same order as that of AlGaAs homojunction LEDs fabricated on the GaAs substrates by liquid phase epitaxy.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Applied Physics Letters (ISSN 0003-6951); 53; 1201-120
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  • 28
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    Extremely low resistance nonalloyed ohmic contacts on GaAs using InAs/InGaAs and InAs/GaAs strained-layer superlattices (1988)
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    Publication Date: 2011-08-19
    Description: Employing a structure consisting of n(+)-InAs/InGaAs and InAs/GaAs strained-layer superlattices (SLSs) grown by molecular beam epitaxy on GaAs films, nonalloyed contact resistances less than 8.5 x 10 to the -8th ohm sq cm have been obtained. Self-consistent simulations show that these extremely small nonalloyed contact resistances are due to the suppression of the depletion depth in the GaAs channel and tunneling through the SLS layer. Similar structures on InGaAs channels have led to nonalloyed specific contact resistances of about 1.5 x 10 to the -8th ohm sq cm. These results represent the smallest figures reported for these important material systems.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Applied Physics Letters (ISSN 0003-6951); 53; 900
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    Analysis of coupled cylindrical striplines filled with multilayered dielectrics (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A method of analysis for coupled cylindrical striplines filled with multilayered dielectrics is presented that uses a variational technique in the space domain. Coupled-mode analysis is presented for the case of a pair of coupled circular arc strips arbitrarily located between cylindrical ground planes filled with multilayered dielectrics. An even- and odd-mode approach is used for the analysis of shielded cylindrically curved edge-coupled pairs of broad-side parallel strips (broad-side, edge-coupled cylindrical striplines). The effect of environmental changes on an otherwise planar structure is also studied by extending the present analysis to cylindrically warped coupled striplines.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Microwave Theory and Techniques (ISSN 0018-9480); 36; 1301-131
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    Noise-margin limitations on gallium-arsenide VLSI (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Two factors which limit the complexity of GaAs MESFET VLSI circuits are considered. Power dissipation sets an upper complexity limit for a given logic circuit implementation and thermal design. Uniformity of device characteristics and the circuit configuration determines the electrical functional yield. Projection of VLSI complexity based on these factors indicates that logic chips of 15,000 gates are feasible with the most promising static circuits if a maximum power dissipation of 5 W per chip is assumed. While lower power per gate and therefore more gates per chip can be obtained by using a popular E/D FET circuit, yields are shown to be small when practical device parameter tolerances are applied. Further improvements in materials, devices, and circuits wil be needed to extend circuit complexity to the range currently dominated by silicon.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Journal of Solid-State Circuits (ISSN 0018-9200); 23; 893-900
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    On the stability, storage capacity, and design of nonlinear continuous neural networks (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The stability, capacity, and design of a nonlinear continuous neural network are analyzed. Sufficient conditions for existence and asymptotic stability of the network's equilibria are reduced to a set of piecewise-linear inequality relations that can be solved by a feedforward binary network, or by methods such as Fourier elimination. The stability and capacity of the network is characterized by the post synaptic firing rate function. An N-neuron network with sigmoidal firing function is shown to have up to 3N equilibrium points. This offers a higher capacity than the (0.1-0.2)N obtained in the binary Hopfield network. Moreover, it is shown that by a proper selection of the postsynaptic firing rate function, one can significantly extend the capacity storage of the network.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Systems, Man, and Cybernetics (ISSN 0018-9472); 18; 80-87
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    Intersubband absorption of silicon-based quantum wells for infrared imaging (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The 10-micron intersubband absorption in quantum wells made of the silicon-based system, Si/Si(1-x)Ge(x), has been calculated. The necessary details of the effective-mass anisotropy are included in the present analysis. It is found that it is readily possible to achieve an absorption constant of order of 10,000/cm in Si quantum wells with current doping technology. For 110-line and 111-line growth directions, a further advantage of Si quantum wells is pointed out, namely, an allowed absorption at normal incidence due to the anisotropic effective mass in Si.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Journal of Applied Physics (ISSN 0021-8979); 64; 1573-157
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    Performance and impedance studies of thin, porous molybdenum and tungsten electrodes for the alkali metal thermoelectric converter (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Columnar, porous, magnetron-sputtered molybdenum and tungsten films show optimum performance as alkali metal thermoelectric converter electrodes at thicknesses less than 1.0 micron when used with molybdenum or nickel current collector grids. Power densities of 0.40 W/sq cm for 0.5-micron molybdenum films at 1200 K and 0.35 W/sq cm for 0.5-micron tungsten films at 1180 K were obtained at electrode maturity after 40-90 h. Sheet resistances of magnetron sputter deposited films on sodium beta-double-prime-alumina solid electrolyte (BASE) substrates were found to increase very steeply as thickness is decreased below about 0.3-double-prime 0.4-micron. The ac impedance data for these electrodes have been interpreted in terms of contributions from the bulk BASE and the porous electrode/BASE interface. Voltage profiles of operating electrodes show that the total electrode area, of electrodes with thickness less than 2.0 microns, is not utilized efficiently unless a fairly fine (about 1 x 1 mm) current collector grid is employed.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Journal of Applied Electrochemistry (ISSN 0021-891X); 18; 410-416
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    High Tc screen-printed YBa2Cu3O(7-x) films - Effect of the substrate material (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Thick films of YBa2Cu3O(7-x) have been deposited on highly polished alumina, magnesia spinel, nickel aluminum titanate (Ni-Al-Ti), and barium tetratitanate (Ba-Ti) substrates by the screen printing technique. Properties of the films were found to be highly sensitive to the choice of the substrate material. The film on Ba-Ti turned green after firing, due to a reaction with the substrate and were insulating. A film on Ni-Al-Ti had a Tc (onset) of about 95 K and lost 90 percent of its resistance by about 75 K. However, even at 4 K it was not fully superconducting, possibly due to a reaction between the film and the substrate and interdiffusion of the reaction products. The film on alumina had Tc (onset) of about 96 K, Tc (zero) of about 66 K, and Delta Tc of about 10 K. The best film was obtained on spinel and had Tc (onset) of about 94 K, zero resistance at 81 K, and a transition width of about 7 K.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Applied Physics Letters (ISSN 0003-6951); 53; 603-605
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    A new model for broadband waveguide-to-microstrip transition design (1988)
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    Publication Date: 2011-08-19
    Description: A new model is presented which permits the prediction of the resonant frequencies created by antipodal finline waveguide to microstrip transitions. The transition is modeled as a tapered transmission line in series with an infinite set of coupled resonant circuits. The resonant circuits are modeled as simple microwave resonant cavities of which the resonant frequencies are easily determined. The model is developed and the resonant frequencies determined for several different transitions. Experimental results are given to confirm the models.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Microwave Journal (ISSN 0192-6225); 31; 333-335
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    Evaluation of the characteristics of a field emission cathode for use in a Mercury ion trap frequency standard (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The performance is reported of a field emission array characterized for the purpose of replacing the filament in a trapped ion frequency standard. This dark electron emitter eliminates the need for the interference filter currently used in the trapped ion standard. While reducing the filament's unwanted light, this filter causes a significant reduction in the signal. The magnetic field associated with the filament is also eliminated, thus potentially improving the present stability of the trapped ion standard. The operation of the filament in the present system is described, as well as the associated concerns. The cathode considered for the filament's replacement is then described along with the experimental system. Experimental results, observations, and conclusions are presented.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Telecommunications and Data Acquisition Report; p 86-92
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    Measurements of induced voltages and currents in a distribution power line and associated atmospheric parameters (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The frequency and intensity of thunderstorms around the Kennedy Space Center (KSC) has affected scheduled launch, landing, and other ground operations for many years. In order to protect against and provide safe working facilities, KSC has performed and hosted several studies on lightning phenomena. For the reasons mentioned above, KSC has established the Atmospheric Science Field Laboratory (ASFL). At these facilities KSC launches wire-towing rockets into thunderstorms to trigger natural lightning to the launch site. A program named Rocket Triggered Lightning Program (RTLP) is being conducted at the ASFL. This report calls for two of the experiments conducted in the summer 1988 Rocket Triggered Lightning Program. One experiment suspended an electric field mill over the launching areas from a balloon about 500 meters high to measure the space charges over the launching area. The other was to connect a waveform recorder to a nearby distribution power line to record currents and voltages wave forms induced by natural and triggered lightning.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA, John F. Kennedy Space Center, NASA(ASEE Summer Faculty Fellowship Program: 1988 Research Reports; p 251-310
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    Cross-guide coupler modeling and design (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Modeling of cross-guide couplers based on the theory of equivalent electric and magnetic dipoles of an aperture is described. Additional correction factors due to nonzero wall thickness and large aperture are also included in this analysis. Comparisons of the measured and calculated results are presented for cross-guide couplers with circular or cross-shaped coupling apertures. A cross-guide coupler was designed as a component of the C-band feed to support the Phobos mission.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Telecommunications and Data Acquisition Report; p 82-88
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    An 8.4-GHz cryogenically cooled HEMT amplifier for DSS 13 (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A prototype 8.4 GHz (X-band) high electron mobility transistor (HEMT) amplifier/closed cycle refrigerator system was installed in the Deep Space Station 13 feedcone in August 1987. The amplifier is cryogenically cooled to a physical temperature of 12 K and provides 31 K antenna noise temperature (zenith) and 35 dB of gain at a frequency of 8.2 to 8.6 GHz. Antenna system noise temperature is less than 50 K from 7.2 to 9.4 MHz. The low noise HEMT amplifier system is intended for use as a radio astronomy or space communications receiver front end.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Telecommunications and Data Acquisition Report; p 163-169
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  • 40
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    Transmitter data collection using Ada (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: A data collection system installed on the 400 kilowatt X-band transmitter of the Goldstone Solar System Radar is described. The data collection system is built around the off-the-shelf IEEE 488 instrumentation, linked with fiber optics, controlled by an inexpensive computer, and uses software written in the Ada language. The speed and accuracy of the system is discussed, along with programming techniques used for both data collection and reduction.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Telecommunications and Data Acquisition Report; p 229-236
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    An extended Kalman filter based automatic frequency control loop (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: An Automatic Frequency Control (AFC) loop based on an Extended Kalman Filter (EKF) is introduced and analyzed in detail. The scheme involves an EKF which operates on a modified set of data in order to track the frequency of the incoming signal. The algorithm can also be viewed as a modification to the well known cross-product AFC loop. A low carrier-to-noise ratio (CNR), high-dynamic environment is used to test the algorithm and the probability of loss-of-lock is assessed via computer simulations. The scheme is best suited for scenarios in which the frequency error variance can be compromised to achieve a very low operating CNR threshold. This technique can easily be incorporated in the Advanced Receiver (ARX), requiring minimum software modifications.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Telecommunications and Data Acquisition Report; p 219-228
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  • 42
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    Modal analysis applied to circular, rectangular, and coaxial waveguides (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Recent developments in the analysis of various waveguide components and feedhorns using Modal Analysis (Mode Matching Method) are summarized. A brief description of the theory is presented, and the important features of the method are pointed out. Specific examples in circular, rectangular, and coaxial waveguides are included, with comparisons between the theory and experimental measurements. Extensions to the methods are described.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Telecommunications and Data Acquisition Report; p 89-96
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    Automatic Detection of Electric Power Troubles (ADEPT) (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Automatic Detection of Electric Power Troubles (A DEPT) is an expert system that integrates knowledge from three different suppliers to offer an advanced fault-detection system. It is designed for two modes of operation: real time fault isolation and simulated modeling. Real time fault isolation of components is accomplished on a power system breadboard through the Fault Isolation Expert System (FIES II) interface with a rule system developed in-house. Faults are quickly detected and displayed and the rules and chain of reasoning optionally provided on a laser printer. This system consists of a simulated space station power module using direct-current power supplies for solar arrays on three power buses. For tests of the system's ablilty to locate faults inserted via switches, loads are configured by an INTEL microcomputer and the Symbolics artificial intelligence development system. As these loads are resistive in nature, Ohm's Law is used as the basis for rules by which faults are located. The three-bus system can correct faults automatically where there is a surplus of power available on any of the three buses. Techniques developed and used can be applied readily to other control systems requiring rapid intelligent decisions. Simulated modeling, used for theoretical studies, is implemented using a modified version of Kennedy Space Center's KATE (Knowledge-Based Automatic Test Equipment), FIES II windowing, and an ADEPT knowledge base.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Lyndon B. Johnson Space Center, 2nd Annual Workshop on Space Operations Automation and Robotics (SOAR 1988); p 47-50
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    SIRE: A Simple Interactive Rule Editor for NICBES (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: To support evolution of domain expertise, and its representation in an expert system knowledge base, a user-friendly rule base editor is mandatory. The Nickel Cadmium Battery Expert System (NICBES), a prototype of an expert system for the Hubble Space Telescope power storage management system, does not provide such an editor. In the following, a description of a Simple Interactive Rule Base Editor (SIRE) for NICBES is described. The SIRE provides a consistent internal representation of the NICBES knowledge base. It supports knowledge presentation and provides a user-friendly and code language independent medium for rule addition and modification. The SIRE is integrated with NICBES via an interface module. This module provides translation of the internal representation to Prolog-type rules (Horn clauses), latter rule assertion, and a simple mechanism for rule selection for its Prolog inference engine.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Alabama Univ., Research Reports: 1988 NASA(ASEE Summer Faculty Fellowship Program; 22 p
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    Development of FIR arrays with integrating amplifiers (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The development of optimized photoconductor arrays suitable for far infrared space astronomical applications are described. Although the primary impetus is the production of a 16 by 16 element Ge:Ga demonstration array for SIRTF, the extension of this technology to Large Deployable Reflector (LDR) is considered. The optimization of Ge:Ga and Ge:Be photoconductor materials is discussed. In collaboration with Lawrence Berkeley Laboratory, measurements of FIR photoconductors with quantum efficiencies greater than 20 percent at 100 micrometers, and dark currents below 300 electrons/s are presented. Integrating J-FET amplifier technology is discussed. The current generation of integrating amplifiers has a demonstrated read noise of less than 20 electrons for an integration time of 100 s. The design is shown for a stackable 16 x n Ge:Ga array that utilizes a 16-channel monolithic version of the J-FET integrator. A part of the design is the use of a thin, thermally insulating substrate that allows the electronics to operate at the optimum temperature of 50 K while maintaining thermal and optical isolation from the detectors at 2 K. The power dissipation for the array is less than 16 mW. The array design may particularly be applicable to high resolution imaging spectrometers for LDR.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Jet Propulsion Lab., California Inst. of Tech., Report of the Asilomar 3 LDR Workshop; p 100
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    Resonant-tunneling oscillators and multipliers for submillimeter receivers (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Resonant tunneling through double-barrier heterostructures has attracted increasing interest recently, largely because of the fast charge transport it provides. In addition, the negative differential resistance regions that exist in the current-voltage (I-V) curve (peak-to-valley ratios of 3.5:1 at room temperature, and nearly 10:1 at 77 K, were measured) suggest that high-speed devices based on the character of the I-V curve should be possible. For example, the negative differential resistance region is capable of providing the gain necessary for high-frequency oscillations. In the laboratory attempts were made to increase the frequency and power of these oscillators and to demonstrate several different high-frequency devices.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Jet Propulsion Lab., California Inst. of Tech., Report of the Asilomar 3 LDR Workshop; p 88-89
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    Random vibration (stress screening) of printed wiring assemblies (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The results of a random vibration test screening (RVSS) study of the determination of the upper and lower vibration limits on printed wiring assemblies (PWA) are summarized. The study results are intended to serve as a guide for engineers and designers who make decisions on PWA features that need to withstand the stresses of dynamic testing and screening. The maximum allowable PWA deflection, G levels, and PSD levels are compared to the expected or actual levels to determine if deleterious effects will occur.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Marshall Space Flight Center, The 58th Shock and Vibration Symposium, Volume 2; p 111-147
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    Polarization of microwave noise source radiation in the 30 GHz to 300 GHz range (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Radiation spectra have been obtained in order to calculate the frequency bandwidth and polarization of three microwave noise sources. Results were obtained in the 1-10-mm wavelength region using a lamellar grating Fourier transform spectrometer and a helium-cooled bolometer detector. A secondary transmission region was found to have an input current as well as a polarization dependence, despite the directional output of the waveguide antenna.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: International Journal of Infrared and Millimeter Waves (ISSN 0195-9271); 9; 1141-115
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    Full temperature single event upset characterization of two microprocessor technologies (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Data for the 9450 I3L bipolar microprocessor and the 80C86 CMOS/epi (vintage 1985) microprocessor are presented, showing single-event soft errors for the full MIL-SPEC temperature range of -55 to 125 C. These data show for the first time that the soft-error cross sections continue to decrease with decreasing temperature at subzero temperatures. The temperature dependence of the two parts, however, is very different.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); 35; 1619-162
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    Annealing results on low-energy proton-irradiated GaAs solar cells (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: AlGaAs/GaAs solar cells with an approximately 0.5-micron-thick Al(0.85)Ga(0.15)As window layer were irradiated using normal and isotropic incident protons having energies between 50 and 500 keV with fluence up to 1 x 10 to the 12th protons/sq cm. The irradiated cells were annealed at temperatures between 150 and 300 C in nitrogen ambient. The annealing results reveal that significant recovery in spectral response at longer wavelengths occurred. However, the short-wavelength spectral response showed negligible annealing, irrespective of the irradiation energy and annealing conditions. This indicates that the damage produced near the AlGaAs/GaAs interface and the space-charge region anneals differently than damage produced in the bulk. This is explained by using a model in which the as-grown dislocations interact with irradiation-induced point defects to produce thermally stable defects.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Journal of Applied Physics (ISSN 0021-8979); 64; 4720-472
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    Modeling of some coplanar waveguide discontinuities (1988)
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    Publication Date: 2011-08-19
    Description: Presented are lumped equivalent circuit models for several coplaar waveguide discontinuities such as an open circuit, a series gap, and a symmetric step, and their element values as a function of the discontinuity physical dimensions. The model element values are de-embedded from measured S parameters. The frequency dependence of the effective dielectric constant is measured and compared to computed values.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Microwave Theory and Techniques (ISSN 0018-9480); 36; 1796-180
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    Approximations useful for the prediction of electrostatic discharges for simple electrode geometries (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The report provides approximations for estimating the capacitance and the ratio of electric field strength to potential for a certain class of electrode geometries. The geometry consists of an electrode near a grounded plane, with the electrode being a surface of revolution about the perpendicular to the plane. Some examples which show the accuracy of the capacitance estimate and the accuracy of the estimate of electric field over potential can be found in the appendix. When it is possible to estimate the potential of the electrode, knowing the ratio of electric field to potential will help to determine if an electrostatic discharge is likely to occur. Knowing the capacitance will help to determine the strength of the discharge (the energy released by it) if it does occur. A brief discussion of discharge mechanisms is given. The medium between the electrode and the grounded plane may be a neutral gas, a vacuum, or an unchanged homogeneous isotropic dielectric.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Electromagnetic Compatibility (ISSN 0018-9375); 30; 473-483
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    Spacecraft electronics design for radiation tolerance (1988)
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    Publication Date: 2011-08-19
    Description: Current design practices are described and future trends in spacecraft electronics which are likely to alter traditional approaches are discussed. A summary of radiation effects and radiation tolerance requirements typically levied on spacecraft designs is provided. Methods of dealing with radiation and testability issues are considered.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE, Proceedings (ISSN 0018-9219); 76; 1527-153
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    The design of radiation-hardened ICs for space - A compendium of approaches (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Several technologies, including bulk and epi CMOS, CMOS/SOI-SOS (silicon-on-insulator-silicon-on-sapphire), CML (current-mode logic), ECL (emitter-coupled logic), analog bipolar (JI, single-poly DI, and SOI) and GaAs E/D (enhancement/depletion) heterojunction MESFET, are discussed. The discussion includes the direct effects of space radiation on microelectronic materials and devices, how these effects are evidenced in circuit and device design parameter variations, the particular effects of most significance to each functional class of circuit, specific techniques for hardening high-speed circuits, design examples for integrated systems, including operational amplifiers and A/D (analog/digital) converters, and the computer simulation of radiation effects on microelectronic ISs.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE, Proceedings (ISSN 0018-9219); 76; 1470-150
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    Determining mode excitations of vacuum electronics devices via three-dimensional simulations using the SOS code (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The SOS code is used to compute the resonance modes (frequency-domain information) of sample devices and separately to compute the transient behavior of the same devices. A code, DOT, is created to compute appropriate dot products of the time-domain and frequency-domain results. The transient behavior of individual modes in the device is then plotted. Modes in a coupled-cavity traveling-wave tube (CCTWT) section excited beam in separate simulations are analyzed. Mode energy vs. time and mode phase vs. time are computed and it is determined whether the transient waves are forward or backward waves for each case. Finally, the hot-test mode frequencies of the CCTWT section are computed.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Electron Devices (ISSN 0018-9383); 35; 2027-203
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    Increased effective barrier heights in Schottky diodes by molecular-beam epitaxy of CoSi2 and Ga-doped Si on Si(111) (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Increasing the effective Schottky-barrier height of epitaxial CoSi2/Si(111) diodes by the use of thin, highly doped Si layers in close proximity to the metal-semiconductor interface has been studied. Intrinsic Si, Si doped by coevaporation of Ga, and epitaxial CoSi2 layers have all been grown in the same molecular-beam epitaxy system. Current-voltage and photoresponse characterization yield barrier heights ranging from 0.61 eV for a sample with no p(+) layer to 0.89 eV for a sample with a 20-nm-thick p(+) layer. These results are compared to theoretical values based on a one-dimensional solution of Poisson's equation under the depletion approximation.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Journal of Applied Physics (ISSN 0021-8979); 64; 4082-408
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    A re-examination of spent beam refocusing for high-efficiency helix TWT's and small MDC's (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The usefulness of the concept of spent-beam refocusing in optimizing the performance of low- and medium-power helix TWTs (traveling-wave tubes) equipped with small multistage depressed collectors (MDCs) is examined. Several direct comparisons of the performance of individually optimized TWT-MDC combinations with and without controlled beam expansion and recollimation are presented. The collector efficiency of a number of representative space and airborne TWT-MDCs, which do not use refocusing, is compared to a measure of quality (standard of excellence) established by an examination of irrecoverable MDC losses. The results suggest that the application of the traditional concept of spent-beam refocusing to most helix TWTs that are equipped with small MDCs in order to obtain maximum efficiency is not required (or even desired). Two effects combine to obviate the need for refocusing: 1) the unexpanded beam more nearly meets the `point source' ideal at the input to the small MDC, and 2) the larger space-charge spreading and the slightly larger (but manageable) injection angles of the unexpanded beam can reduce the amount of backstreaming current and the attendant loss in efficiency.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Electron Devices (ISSN 0018-9383); 35; 539-548
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    1988 IEEE Annual Conference on Nuclear and Space Radiation Effects, 25th, Portland, OR, July 12-15, 1988, Proceedings (1988)
    In:  Other Sources
    Details
    Publication Date: 2016-03-09
    Description: The effects of nuclear and space radiation on the performance of electronic devices are discussed in reviews and reports of recent investigations. Topics addressed include the basic mechanisms of radiation effects, dosimetry and energy-dependent effects, sensors in and for radiation environments, EMP/SGEMP/IEMP phenomena, radiation effects on isolation technologies, and spacecraft charging and space radiation effects. Consideration is given to device radiation effects and hardening, hardness assurance and testing techniques, IC radiation effects and hardening, and single-event phenomena.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: (ISSN 0018-9499)
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    New MBE buffer for micron- and quarter-micron-gateGaAs MESFETs (1988)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: A new buffer layer has been developed that eliminates backgating in GaAs MESFETs and substantially reduces short-channel effects in GaAs MESFETs with 0.27-micron-long gates. The new buffer is grown by molecular beam epitaxy (MBE) at a substrate temperature of 200 C using Ga and As sub 4 beam fluxes. The buffer is crystalline, highly resistive, optically inactive, and can be overgrown with high quality GaAs. GaAs MESFETs with a gate length of 0.27 microns that incorporate the new buffer show improved dc and RF properties in comparison with a similar MESFET with a thin undoped GaAs buffer. To demonstrate the backgating performance improvement afforded by the new buffer, MESFETs were fabricated using a number of different buffer layers and structures. A schematic cross section of the MESFET structure used in this study is shown. The measured gate length, gate width, and source-drain spacing of this device are 2,98, and 5.5 microns, respectively. An ohmic contact, isolated from the MESFET by mesa etching, served as the sidegate. The MESFETs were fabricated in MBE n-GaAs layers grown on the new buffer and also in MBE n-GaAs layers grown on buffer layers of undoped GaAs, AlGaAs, and GaAs/AlGaAs superlattices. All the buffer layers were grown by MBE and are 2 microns thick. The active layer is doped to approximately 2 x 10 to the 17th/cu cm with silicon and is 0.3 microns thick.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Solid State Research; p 31-43
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    Synchronously pumped mode-locked Ti:Al2O3 lasers (1988)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: Synchronously pumped mode-locked laser operation in a Ti:Al2O3 ring laser is demonstrated. The laser pump source was a frequency-doubled Nd:YAG laser-amplifier system producing a 60-micron-long macropulse that comprised a wavetrain of mode-locked 70-ps micropulses with a 10-ns spacing (100 MHz). The Ti:Al2O3 laser consisted of a 1-cm-long crystal with faces cut at the Brewster angle and placed in a ring laser cavity configuration with a 2 percent output coupling mirror. The cavity was adjusted for a 5-ns round trip transit time, which was close to half the temporal spacing of the pump pulse. When the crystal was pumped synchronously at 532 nm with a 30-mJ macropulse, which was approximately an order of magnitude above the laser threshold, mode-locked lasing at approximately 200 MHz was obtained. This macropulse pump energy corresponds to an average micropulse pump energy of about 5 microJ at the Ti:Al2O3 crystal face. The mode-locked operation of the Ti:Al2O3 was observed only after several microseconds into the macropulse, indicating a long build-up process over many cavity trips. During this time, relaxation oscillations were observed. When mode locking started, the relaxation oscillation frequency increased by an order of magnitude. Synchronous pumping has been limited to operation with dye lasers and used either a CW or pulsed mode-locked pump source. Recent work has demonstrated CW mode-locked operation of a Ti:Al2O3 laser. The result raises the possibility that pulsed synchronous pumping may be used to obtain significantly narrowed laser pulses in Ti:Al2O3.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Solid State Research; p 13-22
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    High power density electrodes for AMTEC (1988)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: Trilayer tungsten/platinum electrodes have provided dramatic improvements in stable power densities in alkali metal thermoelectric converters (AMTEC) experimental cells. The specific power density required to achieve a system conversion efficiency of approximately 15 percent or more with temperatures appropriate to space nuclear power sources is examined. Thus, if the observed power densities are sustained for thousands of hours, prototype AMTEC space nuclear power systems can be designed and tested.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: New Mexico Univ., Transactions of the Fifth Symposium on Space Nuclear Power Systems; p 621-623
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    Neutron effects on the electrical and switching characteristics of NPN bipolar power transistors (1988)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: The use of nuclear reactors to generate electrical power for future space missions will require the electrical components used in the power conditioning, control, and transmission subsystem to operate in the associated radiation environments. An initial assessment of neutron irradiation on the electrical and switching characteristics of commercial high power NPN bipolar transistors was investigated. The results clearly show the detrimental effects caused by neutron irradiation on the electrical and switching characteristics of the NPN bipolar power transistor.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: New Mexico Univ., Transactions of the Fifth Symposium on Space Nuclear Power Systems; p 431-435
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    Comb/serpentine/cross-bridge test structure for fabrication process evaluation (1988)
    In:  Other Sources
    Details
    Publication Date: 2018-12-01
    Description: The comb/serpentine/cross-bridge structure was developed to monitor and evaluate same layer shorts and step coverage problems (open and high-resistance wire over steps) for integrated circuit fabrication processes. The cross-bridge provides local measurements of wire sheet resistance and wirewidth. These local parametric measurements are used in the analysis of the serpentine wire, which identifies step coverage problems. The comb/serpentine/cross-bridge structure was fabricated with 3 microns CMOS/bulk p-well process and tested using a computer-controlled parametric test system.
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    Temperature control in wafer-level testing of large multi-segment electromigration test structures (1988)
    In:  Other Sources
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    Publication Date: 2018-12-01
    Description: The paper describes two methods for maintaining a constant metallization temperature throughout a wafer-level isothermal electromigration test of large multisegment test structures where Joule-heating is high and chip to chuck thermal contact is poor. In the first method, an initial calibration of Joule heating versus metal temperature is carried out. During the isothermal electromigration test, the Joule heating is continuously monitored and the chuck temperature is adjusted based on the calibration results to maintain a constant metal temperature. In the second method, temperature sensors are fabricated on the chip and then the sensors are used to monitor the chip temperature directly. The chuck temperature is then adjusted as needed.
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    Comparison of results from simple expressions for MOSFET parameter extraction (1988)
    In:  Other Sources
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    Publication Date: 2018-12-01
    Description: In this paper results are compared from a parameter extraction procedure applied to the linear, saturation, and subthreshold regions for enhancement-mode MOSFETs fabricated in a 3-micron CMOS process. The results indicate that the extracted parameters differ significantly depending on the extraction algorithm and the distribution of I-V data points. It was observed that KP values vary by 30 percent, VT values differ by 50 mV, and Delta L values differ by 1 micron. Thus for acceptance of wafers from foundries and for modeling purposes, the extraction method and data point distribution must be specified. In this paper measurement and extraction procedures that will allow a consistent evaluation of measured parameters are discussed.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
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    Experiences in extraction of contact parameters from process-evaluation test-structures (1988)
    In:  Other Sources
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    Publication Date: 2018-12-01
    Description: Six-terminal-contact test structures are introduced for characterizing ohmic contacts between a metal and a heavily doped semiconductor layer. Specifically, the six-terminal test structure supplies the additional information needed in order to calculate the transmission length and eventual corrections to the characteristic resistance per unit width due to finite contact length. The essential feature of this test structure is a square contact with four taps in the lower (semiconductor) layer. Every other one of these taps is used for current injection ('front'). From the voltage drop at the opposite tap and the side taps, the 'end' resistance and the 'side' resistances are calculated. The test structures are shown to give valuable information complementary to the common front resistance measurements. The interfacial resistivity is obtained directly after proper correction for flange effects.
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    CMOS Process Monitor (1988)
    In:  Other Sources
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    Publication Date: 2018-12-01
    Description: A CMOS Process Monitor, consisting of eight basic test structures, has been prepared to acquire key CMOS parameters to assist in VLSI wafer acceptance. The test structures can be probed using a 2 by N probe pad array and can be arranged to fit into either the interior or the scribe lane of an integrated circuit chip. In order to facilitate the general use of the monitor, a document is being prepared that describes its design, layout, measurement, and analysis. This paper describes the structures included in the monitor, the methodology used to create the monitor, and test results from the monitor.
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    Ku-band high efficiency GaAs MMIC power amplifiers (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The development of Ku-band high efficiency GaAs MMIC power amplifiers is examined. Three amplifier modules operating over the 13 to 15 GHz frequency range are to be developed. The first MMIC is a 1 W variable power amplifier (VPA) with 35 percent efficiency. On-chip digital gain control is to be provided. The second MMIC is a medium power amplifier (MPA) with an output power goal of 1 W and 40 percent power-added efficiency. The third MMIC is a high power amplifier (HPA) with 4 W output power goal and 40 percent power-added efficiency. An output power of 0.36 W/mm with 49 percent efficiency was obtained on an ion implanted single gate MESFET at 15 GHz. On a dual gate MESFET, an output power of 0.42 W/mm with 27 percent efficiency was obtained. A mask set was designed that includes single stage, two stage, and three stage single gate amplifiers. A single stage 600 micron amplifier produced 0.4 W/mm output power with 40 percent efficiency at 14 GHz. A four stage dual gate amplifier generated 500 mW of output power with 20 dB gain at 17 GHz. A four-bit digital-to-analog converter was designed and fabricated which has an output swing of -3 V to +/- 1 V.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-182156 , NAS 1.26:182156
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    Frequency domain laser velocimeter signal processor (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A laser velocimeter signal processor for measuring the signal frequency within a signal burst was invented. The input signal is converted to digital by an analog to digital converter and then shifted into shift registers. An automatic gain circuit controls the gain of the input signal. A signal integration circuit determines when a signal burst has been captured by the shift registers and then transfers the contents of the registers to data latches. The data in the data latches is processed by digital bandpass filters, square law detectors, burst counters and a signal processor to determine the frequency of the signal within the captured signal burst.
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    Laser Doppler velocimeter multiplexer interface for simultaneous measured events (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A laser Doppler velocimeter multiplexer interface includes an event pulse synchronizer which synchronizes data pulses from events A, B, and C. Clock control is connected to receive timing information on the data pulses from the synchronizer. Displays are connected to receive clock signals from the clock control for indicating a data rate for each of the measured events A, B, and C. The display is connected to receive clock signals from the clock control to indicate a coincidence rate between data pulses for any selected combination of the measured events A, B, and C. A multiplexer receives the data pulses from the events A, B, and C and rate data from the clock control. The multiplexer has output for supplying the data pulses and rate data to a single input of a data processing system. A multiplexer control is connected to supply control signals to the multiplexer for selecting the event data pulses and the rate data for output from the multiplexer. The multiplexer control receives start signals from the pulse synchronizer and user selected inputs for desired outputs from the multiplexer.
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    Optical fiber data transfer system (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This Phase 2 effort applies the results of Phase 1 to design and fabricate an optical slip ring system for a helicopter rotor blade/wind tunnel application. In this application, there are two assemblies: one on the rotating portion of the mechanical system, one on the stationary portion. The assembly on the rotating portion digitizes and encodes 128 transducer signals from various parts of the blade, and optically transfers data across the noncontacting coupling. Two complete identical independent channels are provided. On the stationary side, the signals are decoded and one channel is transmitted in digital form to a computer for recording and analysis. The second channel reconstructs the analog transducer signals for real time observation. In the opposite direction, eight signal channels enable control signals to be passed from the stationary to the rotating part of the system. Power to the rotor mounted electronics is supplied via power slip rings. The advantages of the optical over the traditional electro-mechanical slip ring method of data transfer across a rotating joint are long life, low-maintenance, immunity to crosstalk, and wider bandwidth. Successful completion of this effort demonstrated that this method is practical and reliable, and can be implemented under difficult conditions of available space, power, environment, and stringent performance and equipment life requirements.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-181704 , NAS 1.26:181704
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    Functional description of signal processing in the Rogue GPS receiver (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Over the past year, two Rogue GPS prototype receivers have been assembled and successfully subjected to a variety of laboratory and field tests. A functional description is presented of signal processing in the Rogue receiver, tracing the signal from RF input to the output values of group delay, phase, and data bits. The receiver can track up to eight satellites, without time multiplexing among satellites or channels, simultaneously measuring both group delay and phase for each of three channels (L1-C/A, L1-P, L2-P). The Rogue signal processing described requires generation of the code for all three channels. Receiver functional design, which emphasized accuracy, reliability, flexibility, and dynamic capability, is summarized. A detailed functional description of signal processing is presented, including C/A-channel and P-channel processing, carrier-aided averaging of group delays, checks for cycle slips, acquistion, and distinctive features.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-183314 , NAS 1.26:183314 , JPL-PUBL-88-15
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    Development of an adaptive LDV signal processor (1988)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Recent attempts at realization of a frequency domain signal processor exhibit practical drawbacks such as manual gain, filter and sampling adjustments, and simplistic adaptations of frequency domain techniques. This paper introduces an adaptive LDV signal processor, one which requires no operator intervention under any circumstances by adapting dynamically to burst characteristics, while surpassing all previous techniques in range and accuracy.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: AIAA PAPER 88-4673
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    A digitally implemented phase-locked loop detection scheme for analysis of the phase and power stability of a calibration tone (1988)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: A digital phase-locked loop (PLL) scheme is described which detects the phase and power of a high SNR calibration tone. The digital PLL is implemented in software directly from the given description. It was used to evaluate the stability of the Goldstone Deep Space Station open loop receivers for Radio Science. Included is a derivative of the Allan variance sensitivity of the PLL imposed by additive white Gaussian noise; a lower limit is placed on the carrier frequency.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Telecommunications and Data Acquisition Report; p 207-213
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    A 2.3-GHz low-noise cryo-FET amplifier (1988)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: A cryogenic cooled, low-noise Field Effect Transistor (FET) amplifier assembly for use at 2.2 to 2.3 GHz was developed for the DSN to meet the requirements of a Very Long Baseline Interferometry (VLBI) upgrade. An amplifier assembly was developed at JPL that uses a commercial closed-cycle helium refrigerator (CCR) to cool a FET amplifier to an operating temperature of 15 K. A cooled probe waveguide-to-coaxial transition similar to that used in the research and development Ultra-Low-Noise S-band Traveling Wave Maser (TWM) is used to minimize input line losses. Typical performance includes an input flange equivalent noise contribution of 14.5 K, a gain slope of less than 0.05 dB/MHz across a bandwidth of 2.2 to 2.3 GHz, an input VSWR of 1.5:1 at 2.25 GHz, and an insertion gain of 45 + or - 1 dB across the bandwidth of 2.2 to 2.3 GHz. Three 2.3 GHz FET/CCR assemblies were delivered to the DSN in the spring of 1987.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Telecommunications and Data Acquisition Report; p 199-206
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    FTMP data acquisition environment (1988)
    In:  CASI
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    Publication Date: 2019-06-28
    Description: The Fault-Tolerant Multi-Processing (FTMP) test-bed data acquisition environment is described. The performance of two data acquisition devices available in the test environment are estimated and compared. These estimated data rates are used as measures of the devices' capabilities. A new data acquisition device was developed and added to the FTMP environment. This path increases the data rate available by approximately a factor of 8, to 379 KW/S, while simplifying the experiment development process.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-TM-100636 , NAS 1.15:100636
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    Low noise cryogenic dielectric resonator oscillator (1988)
    In:  CASI
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    Publication Date: 2019-06-28
    Description: A microwave oscillator is provided which can operate at a temperature of many degrees above absolute zero while providing very low phase noise that has heretofore generally required temperatures within a few degrees K. The oscillator includes a ring-shaped resonant element of ruby (sapphire plus chromium) or iron sapphire crystal, lying adjacent to a resonator element of sapphire, so that the regenerator element lies directly in the magnetic field of the resonator element. The resonator element is substantially devoid of contact with electrically conductive material. Microwave energy of a pump frequency (e.g., 31 GHz) is outputted from the regenerator element, while signal energy (e.g., 10 GHz) is outputted from the resonator element.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
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    Effects of cosmic rays on single event upsets (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The efforts at establishing a research program in space radiation effects are discussed. The research program has served as the basis for training several graduate students in an area of research that is of importance to NASA. In addition, technical support was provided for the Single Event Facility Group at Brookhaven National Laboratory.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-183053 , NAS 1.26:183053
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    Aging behavior of Au-based ohmic contacts to GaAs (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Gold based alloys, commonly used as ohmic contacts for solar cells, are known to react readily with GaAs. It is shown that the contact interaction with the underlying GaAs can continue even at room temperature upon aging, altering both the electrical characteristics of the contacts and the nearby pn junction. Au-Ge-Ni as-deposited (no heat treatment) contacts made to thin emitter (0.15 micrometer) GaAs diodes have shown severe shunting of the pn junction upon aging for several months at room temperature. The heat-treated contacts, despite showing degradation in contact resistance did not affect the underlying pn junction. Au-Zn-Au contacts to p-GaAs emitter (0.2 micrometer) diodes, however, showed slight improvement in contact resistance upon 200 C isothermal annealing for several months, without degrading the pn junction. The effect of aging on electrical characteristics of the as-deposited and heat-treated contacts and the nearby pn junction, as well as on the surface morphology of the contacts are presented.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-182146 , E-4171 , NAS 1.26:182146
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    A role for high frequency superconducting devices in free space power transmission systems (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Major advances in space power technology are being made in photovoltaic, solar thermal, and nuclear systems. Despite these advances, the power systems required by the energy and power intensive mission of the future will be massive due to the large collecting surfaces, large thermal management systems, and heavy shielding. Reducing this mass on board the space vehicle can result in significant benefits because of the high cost of transporting and moving mass about in space. An approach to this problem is beaming the power from a point where the massiveness of the power plant is not such a major concern. The viability of such an approach was already investigated. Efficient microwave power beam transmission at 2.45 GHz was demonstrated over short range. Higher frequencies are desired for efficient transmission over several hundred or thousand kilometers in space. Superconducting DC-RF conversion as well as RF-DC conversion offers exciting possibilities. Multivoltage power conditioning for multicavity high power RF tubes could be eliminated since only low voltages are required for Josephson junctions. Small, high efficiency receivers may be possible using the reverse Josephson effects. A conceptual receiving antenna design using superconducting devices to determine possible system operating efficiency is assessed. If realized, these preliminary assessments indicate a role for superconducting devices in millimeter and submillimeter free space power transmission systems.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-TM-100971 , E-4264 , NAS 1.15:100971
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    Progress in InP solar cell research (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Progress, in the past year, in InP solar cell research is reviewed. Small area cells with AMO, total area efficiencies of 18.8 percent were produced by OMCVD and Ion Implantation. Larger area cells (2 and 4 sq cm) were processed on a production basis. One thousand of the 2 sq cm cells will be used to supply power to a small piggyback lunar orbiter scheduled for launch in February 1990. Laboratory tests of ITO/InP cells, under 10 MeV proton irradiation, indicate radiation resistance comparable to InP n/p homojunction cells. Computer modeling studies indicate that, for identical geometries and dopant concentrations, InP solar cells are significantly more radiation resistant than GaAs under 1 MeV electron irradiation. Additional computer modeling calculations were used to produce rectangular and circular InP concentrator cell designs for both the low concentration SLATS and higher concentration Cassegrainian Concentrators.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-TM-100914 , E-4166 , NAS 1.15:100914
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    The LDCM actuator for vibration suppression (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A linear dc motor (LDCM) has been proposed as an actuator for the COFS I mast and the COFS program ground test Mini-Mast. The basic principles of operation of the LDCM as an actuator for vibration suppression in large flexible structures are reviewed. Because of force and stroke limitations, control loops are required to stabilize the actuator, which results in a non-standard actuator-plant configuration. A simulation model that includes LDCM actuator control loops and a finite element model of the Mast is described, with simulation results showing the excitation capability of the actuator.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-182898 , NAS 1.26:182898
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    Strategies for concurrent processing of complex algorithms in data driven architectures (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Research directed at developing a graph theoretical model for describing data and control flow associated with the execution of large grained algorithms in a special distributed computer environment is presented. This model is identified by the acronym ATAMM which represents Algorithms To Architecture Mapping Model. The purpose of such a model is to provide a basis for establishing rules for relating an algorithm to its execution in a multiprocessor environment. Specifications derived from the model lead directly to the description of a data flow architecture which is a consequence of the inherent behavior of the data and control flow described by the model. The purpose of the ATAMM based architecture is to provide an analytical basis for performance evaluation. The ATAMM model and architecture specifications are demonstrated on a prototype system for concept validation.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-181657 , NAS 1.26:181657
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    A 30 GHz monolithic receive module technology assessment (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This report is a technology assessment relevant to the 30 GHz Monolithic Receive Module development. It is based on results obtained on the present NASA Contract (NAS3-23356) as well as on information gathered from literature and other industry sources. To date the on-going Honeywell program has concentrated on demonstrating the so-called interconnected receive module which consists of four monolithic chips - the low noise front-end amplifier (LNA), the five bit phase shifter (PS), the gain control amplifier (GC), and the RF to IF downconverter (RF/IF). Results on all four individual chips have been obtained and interconnection of the first three functions has been accomplished. Future work on this contract is aimed at a higher level of integration, i.e., integration of the first three functions (LNA + PS + GC) on a single GaAs chip. The report presents the status of this technology and projections of its future directions.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-180825 , NAS 1.26:180825
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  • 85
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    An automated ozone photometer (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A photometer capable of automatically measuring ozone concentration data to very high resolution during scientific research flights in the Earth's atmosphere was developed at NASA Ames Research Center. This instrument was recently deployed to study the ozone hole over Antarctica. Ozone is detected by absorbing 253.7-nm radiation from an ultraviolet lamp which shines through the sample of air and impinges on a vacuum phototube. A lower output from the phototube indicates more ozone present in the air sample. The photometer employs a CMOS Z80 microprocessor with an STD bus system for experiment control, data collection, and storage. Data are collected and stored in nonvolatile memory for experiments lasting up to 8 hr. Data are downloaded to a portable ground-support computer and processed after the aircraft lands. An independent single-board computer in the STD bus also calculates ozone concentration in real time with less resolution than the CMOS Z80 system, and sends this value to a cockpit meter to aid the pilot in navigation.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-TM-100064 , A-88079 , NAS 1.15:100064
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    Optically interconnected phased arrays (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Phased-array antennas are required for many future NASA missions. They will provide agile electronic beam forming for communications and tracking in the range of 1 to 100 GHz. Such phased arrays are expected to use several hundred GaAs monolithic integrated circuits (MMICs) as transmitting and receiving elements. However, the interconnections of these elements by conventional coaxial cables and waveguides add weight, reduce flexibility, and increase electrical interference. Alternative interconnections based on optical fibers, optical processing, and holography are under evaluation as possible solutions. In this paper, the current status of these techniques is described. Since high-frequency optical components such as photodetectors, lasers, and modulators are key elements in these interconnections, their performance and limitations are discussed.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-TM-100855 , E-4058 , NAS 1.15:100855
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  • 87
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    Development of a 75-watt 60-GHz traveling-wave tube for intersatellite communications (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This program covers the initial design and development of a 75 watt, 60 GHz traveling-wave tube for intersatellite communications. The objective frequency band was 59 to 64 GHz, with a minimum tube gain of 35 dB. The objective overall efficiency at saturation was 40 percent. The tube, designated the 961H, used a coupled-cavity interaction circuit with periodic permanent magnet beam focusing to minimize the weight. For efficiency enhancement, it incorporated a four-stage depressed collector capable of radiation cooling in space. The electron gun had a low-temperature (type-M) cathode and an isolated anode. Two tubes were built and tested; one feasibility model with a single-stage collector and one experimental model that incorporated the multistage collector.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-182135 , W-10301 , NAS 1.26:182135
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    A comparison of frequency estimation techniques for high-dynamic trajectories (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A comparison is presented for four different estimation techniques applied to the problem of continuously estimating the parameters of a sinusoidal Global Positioning System (GPS) signal, observed in the presence of additive noise, under extremely high-dynamic conditions. Frequency estimates are emphasized, although phase and/or frequency rate are also estimated by some of the algorithms. These parameters are related to the velocity, position, and acceleration of the maneuvering transmitter. Estimated performance at low carrier-to-noise ratios and high dynamics is investigated for the purpose of determining the useful operating range of an approximate Maximum Likelihood (ML) estimator, an Extended Kalman Filter (EKF), a Cross-Product Automatic Frequency Control (CPAFC) loop, and a digital phase-locked loop (PPL). Numerical simulations are used to evaluate performance while tracking a common trajectory exhibiting high dynamics.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-184865 , JPL-PUBL-88-21 , NAS 1.26:184865
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    Test results of high-voltage, high-power, solid-state remote power controllers (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This report discusses the results of testing high-voltage, high-power, solid-state remote power controllers (RPC) using RPCs designed and built by John C. Sturman at the Lewis Research Center, Cleveland, Ohio, and utilizing the Autonomously Managed Power Systems (AMPS) breadboard/test facility. These test results are used to determine usefulness of the RPCs for future applications in high-voltage direct-current space power.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-TM-100322 , NAS 1.15:100322
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  • 90
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    Integrated circuit reliability testing (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A technique is described for use in determining the reliability of microscopic conductors deposited on an uneven surface of an integrated circuit device. A wafer containing integrated circuit chips is formed with a test area having regions of different heights. At the time the conductors are formed on the chip areas of the wafer, an elongated serpentine assay conductor is deposited on the test area so the assay conductor extends over multiple steps between regions of different heights. Also, a first test conductor is deposited in the test area upon a uniform region of first height, and a second test conductor is deposited in the test area upon a uniform region of second height. The occurrence of high resistances at the steps between regions of different height is indicated by deriving the measured length of the serpentine conductor using the resistance measured between the ends of the serpentine conductor, and comparing that to the design length of the serpentine conductor. The percentage by which the measured length exceeds the design length, at which the integrated circuit will be discarded, depends on the required reliability of the integrated circuit.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NAS 1.71:NPO-17393-1-CU
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  • 91
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    Development of gallium arsenide high-speed, low-power serial parallel interface modules: Executive summary (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Final report to NASA LeRC on the development of gallium arsenide (GaAS) high-speed, low power serial/parallel interface modules. The report discusses the development and test of a family of 16, 32 and 64 bit parallel to serial and serial to parallel integrated circuits using a self aligned gate MESFET technology developed at the Honeywell Sensors and Signal Processing Laboratory. Lab testing demonstrated 1.3 GHz clock rates at a power of 300 mW. This work was accomplished under contract number NAS3-24676.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-182272 , NAS 1.26:182272
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  • 92
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    On 32-GHz cryogenically cooled HEMT low-noise amplifiers (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The cryogenic noise temperature performance of a two-stage and a three-stage 32 GHz High Electron Mobility Transistor (HEMT) amplifier was evaluated. The amplifiers employ 0.25 micrometer conventional AlGaAs/GaAs HEMT devices, hybrid matching input and output microstrip circuits, and a cryogenically stable dc biasing network. The noise temperature measurements were performed in the frequency range of 31 to 33 GHz over a physical temperature range of 300 K down to 12 K. Across the measurement band, the amplifiers displayed a broadband response, and the noise temperature was observed to decrease by a factor of 10 in cooling from 300 K to 15 K. The lowest noise temperature measured for the two-stage amplifier at 32 GHz was 35 K with an associated gain of 16.5 dB, while the three-stage amplifier measured 39 K with an associated gain of 26 dB. It was further observed that both amplifiers were insensitive to light.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Telecommunications and Data Acquisition Report; p 71-81
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    Microwave characteristics of interdigitated photoconductors on a HEMT structure (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Interdigitated photoconductive detectors of various geometries were fabricated on AlGaAs/GaAs heterostructure material. The processes used in the fabrication of these devices are described, and the results of a study of their optical and electrical characteristics are presented.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-182197 , NAS 1.26:182197
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    Power quality load management for large spacecraft electrical power systems (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: In December, 1986, a Center Director's Discretionary Fund (CDDF) proposal was granted to study power system control techniques in large space electrical power systems. Presented are the accomplishments in the area of power system control by power quality load management. In addition, information concerning the distortion problems in a 20 kHz ac power system is presented.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-TM-100342 , NAS 1.15:100342
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    A millimeter-wave tunneLadder TWT (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A millimeter wave traveling wave tube was developed using a dispersive, high impedance forward interaction structure based on a ladder, with non-space harmonic interaction, for a tube with high gain per unit length and high efficiency. The TunneLadder interaction structure combines ladder properties modified to accommodate Pierce gun beam optics in a radially magnetized permanent magnet focusing structure. The development involved the fabrication of chemically milled, shaped ladders diffusion brazed to diamond cubes which are in turn active-diffusion brazed to each ridge of a doubly ridged waveguide. Cold test data are presented, representing the omega-beta and impedance characteristics of the modified ladder circuit. These results were used in small and large signal computer programs to predict TWT gain and efficiency. Actual data from tested tubes verify the predicted performance while providing broader bandwidth than expected.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-182184 , NAS 1.26:182184
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    X-band resonant ring operation at 450 kW (1988)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The operation of the X-band (7.2 GHz) ring resonator was documented at a power level of 450 kW, which represents the highest power level achieved in the resonator to date. The ring resonator and the overall experimental setup are summarized. The motivation for the present ring resonator experiment is described, and specific results are presented. More general observations made while operating the ring at these power levels are described, and conclusions are drawn.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Telecommunications and Data Acquisition Report; p 18-26
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    Hermetically sealable package for hybrid solid-state electronic devices and the like (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A light-weight, inexpensively fabricated, hermetically sealable, repairable package for small electronic or electromechanical units, having multiple connections, is described. A molded ring frame of polyamide-imide plastic (Torlon) is attached along one edge to a base plate formed of a highly heat conducting material, such as aluminum or copper. Bores are placed through a base plate within the area of the edge surface of ring frame which result in an attachment of the ring frame to the base plate during molding. Electrical leads are molded into the ring frame. The leads are L-shaped gold-plated copper wires imbedded within widened portions of the side wall of the ring frame. Within the plastic ring frame wall the leads are bent (typically, though not necessarily at 90 deg) so that they project into the interior volume of the ring frame for connection to the solid state devices.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
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  • 98
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    Arc lamp power supply using a voltage multiplier (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A power supply is provided for an arc discharge lamp which includes a relatively low voltage high current power supply section and a high voltage starter circuit. The low voltage section includes a transformer, rectifier, variable resistor and a bank of capacitors, while the starter circuit comprises several diodes and capacitors connected as a Cockcroft-Walton multiplier. The starting circuit is effectively bypassed when the lamp arc is established and serves to automatically provide a high starting voltage to re-strike the lamp arc if the arc is extinguished by a power interruption.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
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  • 99
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    Microwave response of an HEMT photoconductor (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Interdigitated photodetectors of various geometries have been fabricated on GaAlAs/GaAs heterostructure material. Optical response characteristics of these devices have been examined at both dc and microwave frequencies. The microwave response, at frequencies to 8 GHz, was studied by illuminating the devices with the output of an internally modulated GaAlAs diode laser. Results of these measurements are presented and compared with that of GaAs photoconductors.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-TM-100819 , E-4009 , NAS 1.15:100819
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    SETI data controllers (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Three data controllers developed for the SETI project are described. Two are used primarily for recording and playback of SETI data from the Radio Science Surveillance System (RSSS). The third is used as a SETI station controller for DSS 13.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Telecommunications and Data Acquisition Report; p 184-190
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