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  • Polymer and Materials Science  (2,626)
  • INSTRUMENTATION AND PHOTOGRAPHY  (249)
  • COMMUNICATIONS AND RADAR
  • 1980-1984
  • 1975-1979  (3,041)
  • 1950-1954
  • 1976  (3,041)
Collection
Keywords
Publisher
Years
  • 1980-1984
  • 1975-1979  (3,041)
  • 1950-1954
Year
  • 1
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    A combined boundary-profile and automated data-reduction and analysis system (1976)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: A portable boundary-layer meteorological data-acquisition and analysis system is described which employs a small tethered balloon and a programmable calculator. The system is capable of measuring pressure, wet- and dry-bulb temperature, wind speed, and temperature fluctuations as a function of height and time. Other quantities, which can be calculated in terms of these, can also be made available in real time. All quantities, measured and calculated, can be printed, plotted, and stored on magnetic tape in the field during the data-acquisition phase of an experiment.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Boundary-Layer Meteorology; 10; Aug. 197
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  • 2
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    Reconstructing color images of astronomical objects using black and white spectroscopic emulsions (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A color photograph of the peculiar elliptical galaxy NGC 5128 (Centaurus A) has been reconstructed from three Kodak 103a emulsion type photographs by projecting positives of the three B&W plates through appropriate filters onto a conventional color film. The resulting photograph shows color balance and latitude characteristics superior to color photographs of similar astronomical objects made with commercially available conventional color film. Similar results have been obtained for color reconstructed photographs of the Large and Small Magellanic Clouds. These and other results suggest that these projection-reconstruction techniques can be used to obtain high-quality color photographs of astronomical objects which overcome many of the problems associated with the use of conventional color film for the long exposures required in astronomy.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Applied Photographic Engineering; 2; Spring 1
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  • 3
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    Testing of a photoelectric photometer. 2: Observational testing (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The versatility is demonstrated of the 41 cm. Tortugas reflector's photoelectric system through observations of V566 Oph and R CrB with four associated AAVSO comparison stars. These observations were made between May and October, 1974.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Contrib. of the Observatory of N. Mex. State Univ., Vol. 1, No. 4; p 154-158
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  • 4
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    Large-area multi-crystal NaI/Tl/ detectors for X-ray and gamma-ray astronomy (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: An array of large multicrystal NaI(Tl) detectors was constructed and used in a balloon-borne experiment to observe weak transient bursts of cosmic origin. The array had an active area of about 1 sq m and was sensitive to photons above 50 keV. Localized bursts which were observed are attributed to long-lived phosphorescence following large energy deposits by cosmic rays in the crystals.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Nuclear Instruments and Methods; 140; 1976
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  • 5
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    The Communications Technology Satellite /CTS/ Program (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The purposes of the joint Canadian-U.S. Communications Technology Satellite (CTS) Program are (1) to conduct satellite communication systems experiments using the 12- and 14-GHz bands and low-cost transportable ground terminals, (2) to develop and flight test a power amplifier tube having a greater than 50% efficiency with a saturated power output of 200 W at 12 GHz, (3) to develop and flight test a lightweight extendible solar array with an initial power output greater than 1 kW, and (4) to develop and flight test a 3-axis stabilization system to maintain accurate antenna boresight positioning on a spacecraft with flexible appendages. Brief descriptions of these experiments and of the ground facilities are provided.
    Keywords: COMMUNICATIONS AND RADAR
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  • 6
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    CCD correlation techniques (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Two CCD techniques were discussed for performing an N-point sampled data correlation between an input signal and an electronically programmable reference function. The design and experimental performance of an implementation of the direct time correlator utilizing two analog CCDs and MOS multipliers on a single IC were evaluated. The performance of a CCD implementation of the chirp z transform was described, and the design of a new CCD integrated circuit for performing correlation by multiplication in the frequency domain was presented. This chip provides a discrete Fourier transform (DFT) or inverse DFT, multipliers, and complete support circuitry for the CCD CZT. The two correlation techniques are compared.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: JPL Conf. on Charge-Coupled Device Technol. and Appls.; 6 p
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  • 7
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    RECON 6: A real-time, wide-angle, solid-state reconnaissance camera system for high-speed, low-altitude aircraft (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The maturity of self-scanned, solid-state, multielement photosensors makes the realization of "real time" reconnaissance photography viable and practical. A system built around these sensors which can be constructed to satisfy the requirements of the tactical reconnaissance scenario is described. The concept chosen is the push broom strip camera system -- RECON 6 -- which represents the least complex and most economical approach for an electronic camera capable of providing a high level of performance over a 140 deg wide, continuous swath at altitudes from 200 to 3,000 feet and at minimum loss in resolution at higher altitudes.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: JPL Conf. on Charge-Coupled Device Technol. and Appls.; p 129-134
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  • 8
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    High data rate performance of a BCCD for rapid scan imaging (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A commercially available 1728 element shallow bulk channel CCD line array was clocked at output data rates up to 30 MHz. Temporal noise was near 200 electrons and was largely independent of clock rate. Charge transfer efficiency was in excess of 0.9999 at 30 MHz. Utilization is feasible for visual simulation and aerial mapping.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: JPL Conf. on Charge-Coupled Device Technol. and Appls.; p 72-82
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  • 9
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    Development of large area CCD imagers (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: High performance CCD imagers with 800 x 50 resolution elements were fabricated using a coplanar, double polysilicon, electrode system. The imager was developed as a prototype to demonstrate the feasibility of an 800 x 800 array for application to deep space photography where data rates of 10K to the 2nd power and operating temperatures of -40 C are required. The performance is discussed and comparisons made to the existing 400 x 400 imager.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: JPL Conf. on Charge-Coupled Device Technol. and Appls.; 3 p
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  • 10
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    Television applications of interline-transfer CCD arrays (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The design features and characteristics of interline transfer (ILT) CCD arrays with 190 x 244 and 380 x 488 image elements are reviewed, with emphasis on optional operating modes and system application considerations. It was shown that the observed horizontal resolution for a TV system using an ILT image sensor can approach the aperture response limit determined by photosensor site width, resulting in enhanced resolution for moving images. Preferred camera configurations and read out clocking modes for maximum resolution and low light sensitivity are discussed, including a very low light level intensifier CCD concept. Several camera designs utilizing ILT-CCD arrays are described. These cameras demonstrate feasibility in applications where small size, low-power/low-voltage operation, high sensitivity and extreme ruggedness are either desired or mandatory system requirements.
    Keywords: COMMUNICATIONS AND RADAR
    Type: JPL Conf. on Charge-Coupled Device Technol. and Appls.; p 152-156
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  • 11
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    Television cameras employing solid-state imaging sensors for manned spacecraft applications (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The Space Shuttle television system incorporates a versatile complement of TV equipment which allows the positioning, quantity, and performance capabilities of the multiple TV cameras to vary as dictated by the particular mission. However, current TV camera technology employing glass enclosed, vacuum processed image sensors results in a bulky device that restricts its location and versatility. Problems and potential solutions that can be achieved through the employment of solid-state image sensors for both monochrome and color applications are discussed.
    Keywords: COMMUNICATIONS AND RADAR
    Type: JPL Conf. on Charge-Coupled Device Technol. and Appls.; p 126-128
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  • 12
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    Command detector SNR estimator and lock status monitor circuitry (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A breadboard of the command detector signal-to-noise-ratio estimator and lock status monitor was built on a wire-wrap card. The breadboard was integrated with the standard command detector, and its performance was measured. The design, design constraints, and construction of the breadboard are described. The performance is shown to agree with the theoretical model.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 42-51
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  • 13
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    Improved acoustic viscosimeter technique (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: An improved technique has been developed for studies of the shear viscosity of fluids. It utilizes an acoustic resonator as a four-terminal electrical device; the resonator's amplitude response may be determined directly and simply related to the fluid's viscosity. The use of this technique is discussed briefly and data obtained in several fluids is presented.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Acoustical Society of America; vol. 60
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  • 14
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    The scattering of obliquely incident plane waves from a corrugated conducting surface (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A physical optics solution is presented for the scattering of plane waves from a perfectly conducting corrugated surface in the case of waves incident from an arbitrary direction and for an observer far from the surface. This solution is used to compute the radar cross section of the surface in the case of backscatter from irregular (i.e., stochastic) corrugations. An interesting feature of the solution is the occurrence of singularities in the scattered fields. These singularities appear to be a manifestation of focusing by the surface at its 'stationary' points. Whether or not the singularities occur in the solution depends on the manner in which one restricts the analysis to the far-field.
    Keywords: COMMUNICATIONS AND RADAR
    Type: IEEE Transactions on Antennas and Propagation; AP-24; Nov. 197
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  • 15
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    Photographic image intensification by autoradiography (1976)
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    Publication Date: 2011-08-17
    Description: Images on developed photographic emulsions can be significantly intensified by making the image silver radioactive and exposing a second emulsion to this radiation. Because the print, an autoradiograph, reproduces the original with significant increases in density and contrast, the method can be used to enhance underexposed emulsions and to increase the limits of photographic detection. This paper reports a new, practical chemical method for activating the silver, using thiourea labeled with sulfur-35, a process convenient for use in photographic laboratories. Speed increases of 13 and contrast increases of 18 were achieved with Kodak Plus-X film in this initial phase.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 15; Nov. 197
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  • 16
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    Charge coupled device integration-time coding for detection of images moving with unknown velocities (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Existing techniques for the detection of a moving low light level image by a CCD array have required velocity synchronism between the image and the photogenerated charges. This was necessary to prevent blurring during the long duration of charge integration. A new detection scheme is described which causes the image to be convolved with a clock modulation signal as the photocharges are collected. The charge accumulating from each image point will now be spread over many photoelements due to the absence of velocity synchronism, but the output is not blurred in the usual sense. Instead the charge is distributed through the array in a controlled way so that the image can be reconstructed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: JPL Conf. on Charge-Coupled Device Technol. and Appls.; p 139-144
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  • 17
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    Recent progress in photoelectron image detection with CCDs (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Intensified CCDs (ICCDs) were built and operated. These ICCDs were electrostatically and magnetically-focussed image tubes which use CCDs as anodes. The ICCDs detected single photoelectrons, and have electron gain very near that which was predicted. The first single-pixel pulse-height distributions were presented, and the leakage current was shown to increase as a function of photoelectron irradiation. The advantages and disadvantages of front- and rear-illuminated designs were discussed in light of differing applications requirements.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: JPL Conf. on Charge-Coupled Device Technol. and Appls.; p 101-105
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  • 18
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    Low-noise video amplifiers for imaging CCD's (1976)
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    Publication Date: 2011-08-17
    Description: Various techniques were developed which enable the CCD (charge coupled device) imaging array user to obtain optimum performance from the device. A CCD video channel was described, and detector-preamplifier interface requirements were examined. A noise model for the system was discussed at length and laboratory data presented and compared to predicted results.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: JPL Conf. on Charge-Coupled Device Technol. and Appls.; p 83-88
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  • 19
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    Radio frequency boresight analysis of the low cost 64-meter antenna (1976)
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    Publication Date: 2011-08-17
    Description: Configurations (two) of the reflector-only assemblies, using different width backup cones, are analyzed for RF boresight direction changes and wind distortions. The wider backup cone is best for minimum weight; however, there is an optimum weight which minimizes the RF boresight errors for a wind load that produces the maximum pitching moment of both configurations.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 128-135
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  • 20
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    Magnitude of 64-m elevation axis movements due to alidade temperature changes (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: In projected very-long baseline interferometry (VLBI) work a reference point for 64-m antennas is the intersection of the elevation and azimuth axes. A minimum-level effort at DSS 14 to determine the magnitude of the effect of diurnal changes in the temperature of the alidade legs on the height of the elevation axis is described. The thermal expansion between the lowest recorded temperature -3 C (27 F) and the highest, 36 C (97 F), over the period covered was 8.9 mm (0.35 in.).
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Deep Space Network; p 41-44
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  • 21
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    Si/Li/ X-ray astronomical spectroscopy (1976)
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    Publication Date: 2011-08-16
    Description: The principles of operation of solid state nondispersive spectrometers are reviewed. Si(Li) is shown to be the preferred nondispersive X-ray spectrometer because of its inherent resolution advantages and its adaptability to the constraints and philosophy of the HEAO-B observatory. A schematic diagram is presented of the geometry of the HEAO-B solid state detector assembly as a block diagram of the primary logic mode of the HEAO-B X-ray spectrometer.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
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  • 22
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    Remote intensity fluctuation measurements with a laser Doppler radar (1976)
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    Publication Date: 2011-08-16
    Description: A coaxial focused CW scanning laser Doppler velocimeter (SLDV) radar equipment applying heterodyne detection at 10.6 microns can measure intensity fluctuations under field conditions. The set includes a 20 W CO2 laser, a coaxial Cassegrainian telescope, standard heterodyne equipment, and a SAW spectrum analyzer with 100 kHz signal resolution. Operation of the equipment and techniques for taking remote measurements are described briefly. Applications to remote measurements of transverse component of wind speed, as a complement to the traditional Doppler method of determining axial velocity, are under study. SLDV equipment has been used in detection, tracking, and measurements of atmospheric turbulence associated with aircraft wing-tip vortices or with dust devils, and in measurement of general atmospheric wind profiles.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Applied Optics; 15; Sept
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  • 23
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    Development of a water vapor radiometer to correct for tropospheric range delay in DSN applications (1976)
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    Publication Date: 2011-08-16
    Description: The rationale for a Water Vapor Radiometer (WVR) as an aid in predicting tropospheric delay correction is presented. Included is a block diagram and a description of the present developmental WVR with the semiautomated operating sequence outlined. A brief summary of field tests at El Monte airport and Pt. Mugu is given.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The Deep Space Network; p 77-84
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  • 24
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    New sidelobe envelopes for small aperture earth stations (1976)
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    Publication Date: 2011-08-16
    Description: The advent of domestic satellite systems and technological improvements in both space and ground equipment makes the use of small aperture earth stations economically feasible and attractive for broadcast satellite applications. With increasing use of the orbit spectrum, there is some concern that broadcast satellite systems may not be able to obtain satisfactory allocations of this orbit-spectrum resource because of interference considerations. Specifically, interference calculations based on the present envelope result in comparatively large orbit spacings for broadcast satellites. Theoretical and experimental investigations of simple sidelobe suppression techniques, plus an analysis of experimental data on small aperture antennas, indicate that much better sidelobe performance can be obtained with a very small cost or performance penalty.
    Keywords: COMMUNICATIONS AND RADAR
    Type: IEEE Transactions on Broadcasting; BC-22; June 197
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  • 25
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    The input admittance of the rectangular cavity-backed slot antenna (1976)
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    Publication Date: 2011-08-16
    Description: The input admittance of the rectangular cavity-backed slot antenna is investigated. The slot is assumed narrow so that the voltage distribution in its aperture is sinusoidal. Equations which represent the input admittance of this slot, backed by a rectangular cavity in which a single propagating wave is assumed to exist, are given. Calculations based on these representations are compared to available measured data. As the depth of the cavity increased the resonant frequency decreased and the bandwidth became narrower. Input admittance curves as a function of electrical slot length are also presented for several size cavities.
    Keywords: COMMUNICATIONS AND RADAR
    Type: IEEE Transactions on Antennas and Propagation; AP-24; May 1976
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  • 26
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    Mechanical testing - In situ fracture device for Auger electron spectroscopy (1976)
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    Publication Date: 2011-08-16
    Description: An in situ fracture device for Auger spectroscopy is described. The device is designed to handle small tensile specimens or small double-cantilever beam specimens and is fully instrumented with load and displacement transducers so that quantitative stress-strain measurements can be made directly. Some initial test results for specimens made from 4130 and 1020 steel are presented. Results indicate that impurity segregation at interfaces other than grain boundary may play a significant role in the mechanism of ductile fracture.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments; 47; Apr. 197
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  • 27
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    Power conservation for reflector antennas with truncated feed patterns (1976)
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    Publication Date: 2011-08-16
    Description: Reflector-antenna calculations using idealised truncated feed patterns can lead to incorrect values of total secondary radiated power. It is demonstrated that this discrepancy is due to the presence of higher-order spherical modes incident on the reflector. When a proper spherical-wave expansion of the incident field is used, in conjunction with the physical-optics technique, to determine the scattered field, the total power of the scattered field will equal the power radiated by the feed.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Electronics Letters; 12; Mar. 18
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  • 28
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    Sensitivity of an astronomical infrared heterodyne spectrometer (1976)
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    Publication Date: 2011-08-16
    Description: The factors determining the sensitivity of a real astronomical heterodyne spectrometer are described. The deviation from the ideal heterodyne system for line detection is described in terms of a series of degradation factors. A discussion of degradation due to a low local oscillator power and to line profile detection is presented. Representative values for the degradation factors are given. Even with a total degradation of not less than 30, the heterodyne spectrometer is still found to be a highly sensitive tool in IR astronomy.
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  • 29
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    Infrared upconversion for astronomical applications (1976)
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    Publication Date: 2011-08-16
    Description: The performance of an upconversion system is examined for observation of astronomical sources in the low to middle IR spectral range. Theoretical values for the performance parameters of an upconversion system for astronomical observations are evaluated in terms of the conversion efficiencies, spectral resolution, field of view minimum detectable source brightness, and source flux. Experimental results of blackbody measurements and molecular absorption-spectrum measurements using a lithium niobate upconverter with an argon-ion laser as the pump are presented. Estimates are given of the expected optimum sensitivity of an upconversion device that may be built with presently available components.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 15; Apr. 197
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  • 30
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    Satellite communications at the Goddard Space Flight Center (1976)
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    Publication Date: 2011-08-16
    Description: Starting with the 1960 Delta launch of the first Echo satellite, NASA's Goddard Space Flight Center (GSFC) became one of the pioneers in satellite communications. Attention is given to the project Syncom, the Applications Technology Satellite (ATS) program, the ATS-6 project, and current GSFC efforts. After the decision announced in January of 1973 that NASA would phase out of communications satellite programs, the communications effort at GSFC concentrates on the operation of ATS spacecraft in orbit, experiments in the 12- to 14 GHz frequency band, and advanced communications research.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Signal; 30; Mar. 197
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  • 31
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    Upconversion spectrometry for astrophysical applications (1976)
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    Publication Date: 2011-08-16
    Description: Black body measurements and absorption spectra of methane near 3.3 microns are presented and used as examples in a discussion of upconversion spectrometry for astrophysical application. Factors determining the system conversion efficiency and the minimum detectable flux for a typical system are presented. The spectrometer described uses an Argon-ion laser and a temperature turned LiNbO3 crystal in a CW mode. Satisfactory agreement between measured and calculated performance parameters is obtained. An estimate of the highest performance parameters attainable using current technology is given.
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  • 32
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    Real-time video compression algorithm for Hadamard transform processing (1976)
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    Publication Date: 2011-08-16
    Description: A real-time digital video processor using Hadamard transform techniques to reduce video bandwidth is described. The processor can be programmed with different parameters to investigate various algorithms for bandwidth compression. The processor is also adaptive in that it can select different parameter sets to tradeoff spatial resolution for temporal resolution in the regions of the picture that are moving. Algorithms used in programming the system are described along with results achieved at various levels of compression. The algorithms relate to spatial compression, temporal compression, and the adaptive selection of parameter sets.
    Keywords: COMMUNICATIONS AND RADAR
    Type: IEEE Transactions on Electromagnetic Compatibility; EMC-18; Feb. 197
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  • 33
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    Effect of velocity gradients on measurements of turbulent shear stress (1976)
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    Publication Date: 2011-08-16
    Description: Experiments were carried out to evaluate the effects of normal velocity gradients on hot wire measurements in a subsonic boundary layer of the same size as the flow investigated by Johnson and Rose (1975). Both hot wire and film anemometers were used to measure the turbulent properties of the boundary layer. A special X-wire probe with one wire vertical and the other at an angle of about 40 deg to the flow was used to demonstrate the gradient effects. The results indicate that major errors are encountered when mean and turbulent velocity gradients exist along the length of hot wire sensors, the problem being more pronounced at high speeds. Although the split film sensor results show a significant improvement over the X-wire sensor, further reduction in the space resolution of sensors by roughly an order of magnitude would appear to be necessary to reduce the error to acceptable values near the wall.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AIAA Journal; 14; Mar. 197
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    Experimental design of laminar proportional amplifiers (1976)
    In:  CASI
    Details
    Publication Date: 2012-05-19
    Description: An experimental program was initiated at Langley Research Center to study the effects of various parameters on the design of laminar proportional beam deflection amplifiers. Matching and staging of amplifiers to obtain high-pressure gain was also studied. Variable parameters were aspect ratio, setback, control length, receiver distance, receiver width, width of center vent, and bias pressure levels. Usable pressure gains from 4 to 19 per stage can now be achieved, and five amplifiers were staged together to yield pressure gains up to 2,000,000.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AGARD Fluidics Technol.; p 209-227
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  • 35
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    Frequencies above 10 GHz (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The paper discusses some of the problems associated with extending the frequencies used by satellite communication services above 10 GHz. The principal propagation limitation above 10 GHz occurs when precipitation intercepts the earth-space propagation path and causes attenuation and depolarization of the transmitted signal. World attenuation statistics at 12 GHz for earth-space paths are discussed, revealing the effect of climate on attenuation properties. Space diversity is discussed as an effective means of overcoming precipitation-caused attenuation problems.
    Keywords: COMMUNICATIONS AND RADAR
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  • 36
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    Magnetometers using RF-driven squids and their applications in rock magnetism and paleomagnetism (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Reviews of Geophysics and Space Physics; 14; Nov. 197
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  • 37
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    Diffraction effects on angular response of X-ray collimators (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Angular responses have been measured for X-ray collimators with half-widths ranging from minutes of arc down to 10 arcsec. In the seconds-of-arc range, diffraction peaks at off-axis angles can masquerade as side lobes of the collimator angular response. Measurements and qualitative physical arguments lead to a rule of thumb for collimator design; namely, the angle of first minimum in the Fraunhofer single-slit diffraction pattern should be less than one-fourth of the collimator geometrical full-width at half-maximum intensity.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments; 47; Aug. 197
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  • 38
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    Photometric calibration of planetary photographs (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The basic data and approach for calibrating photographic plates obtained with the 61 cm telescope at the Tortugas Mountain Station of New Mexico State University are summarized. Since this is the fundamental calibration of planetary data it is of use to all in-house users as well as other individuals who use the data.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Contrib. of the Observatory of N. Mex. State Univ., Vol. 1, No. 4; p 159-163
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  • 39
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    Testing of a photoelectric photometer. 1: Determination of operational parameters (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Observations over four months are used to evaluate magnitude and color transformations, extinction coefficients, and a gain table for the photoelectric photometer of the 41 cm. reflector at the Tortugas Mountain site. Ways of increasing the efficiency and accuracy of this system are discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Contrib. of the Observatory of N. Mex. State Univ., Vol. 1, No. 4; p 148=153
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  • 40
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    Sensitivity limits of an infrared heterodyne spectrometer for astrophysical applications (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A discussion and an evaluation of the degradation in sensitivity are given for a heterodyne spectrometer employing a HgCdTe photodiode mixer and tunable diode lasers. The minimum detectable source brightness is considered as a function of the mixer parameters, transmission coefficient of the beam splitter, and local oscillator emission powers. The degradation in the minimum detectable line source brightness that results from the bandwidth being a fraction of the line width is evaluated and plotted as a function of the wavelength and bandwidth for various temperature to mass ratios. It is shown that the minimum achievable degradation in the sensitivity of a practical astronomical heterodyne spectrometer is about 30. Estimates of SNRs with which IR line emission from astronomical sources of interest may be detected are given.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 15; Feb. 197
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    Use of dynamic theory to describe experimental results from volume holography (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The general applicability of dynamic theory to the description of the recording and readout characteristics of volume (thick) hologram gratings is indicated. In dynamic theory (as opposed to static theory), the volume nature of the thick holographic grating allows the interference of an incident light beam with its own diffracted beam inside the recording medium. This effect causes the continuous recording of another grating that alters the initial one, producing a resultant grating that is not uniform through the thickness of the recording material and a grating whose writing and reading characteristics may vary dramatically, depending on the recording material and the experimental conditions. A large number of diverse types of writing, reading, and angular-selectivity behavior have been reported. The dynamic theory of thick-hologram writing and reading is shown to predict qualitatively all of these various types of experimental behavior.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Applied Physics; 47; Jan. 197
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  • 42
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    Analysis of the radiation patterns of reflector antennas (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The development and application of a numerical technique for rapid calculation of the far-field radiation patterns of a reflector antenna from either a measured or computed feed pattern are reported. The reflector is defined by the intersection of a cone with any surface of revolution or an offset sector of any surface of revolution. The feed is assumed to be linearly polarized and can have an arbitrary location. Both the copolarized and the cross-polarized reflector radiation patterns are computed. Calculations using the technique compare closely with measured radiation patterns of a waveguide-fed offset parabolic reflector. Unique features of this technique are freedom from restrictive feed assumptions and the numerical methods used in preparing the aperture-plane electric-field data for integration.
    Keywords: COMMUNICATIONS AND RADAR
    Type: IEEE Transactions on Antennas and Propagation; AP-24; Jan. 197
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    Image quality prediction - An aid to the Viking lander imaging investigation on Mars (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Image quality criteria and image quality predictions are formulated for the multispectral panoramic cameras carried by the Viking Mars landers. Image quality predictions are based on expected camera performance, Mars surface radiance, and lighting and viewing geometry (fields of view, Mars lander shadows, solar day-night alternation), and are needed in diagnosis of camera performance, in arriving at a preflight imaging strategy, and revision of that strategy should the need arise. Landing considerations, camera control instructions, camera control logic, aspects of the imaging process (spectral response, spatial response, sensitivity), and likely problems are discussed. Major concerns include: degradation of camera response by isotope radiation, uncertainties in lighting and viewing geometry and in landing site local topography, contamination of camera window by dust abrasion, and initial errors in assigning camera dynamic ranges (gains and offsets).
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 15; July 197
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  • 44
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    Contactless method of measuring resistivity (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A method is described for measuring the conductivity of materials without having to make electrical contact with the material. Currents which are magnetically induced in the conducting sample are measured by means of the magnetic fields they produce. Although induction techniques have been used in the past for this type of measurement, the configuration presented here makes it possible to perform absolute measurements of resistivity over a wide range of values for relatively small samples. The theory of the technique, the results of measurements made with it, and a comparison of the technique with other methods are presented.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments; 47; June 197
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  • 45
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    Doppler-shifted reflections of X rays in beamfoil spectroscopy (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Carbon foils were positioned at roughly 10 deg to the conventional perpendicular position so that the spectrometer would view the beam on emergence from the foil, with no radiation shielded by a bowed or wrinkled foil or by the foil holder. Extraneous peaks due to reflected radiation were detected in the spectrum obtained with the tilted foil. A large satellite appears longward of the spectral line and is attributed to Doppler-shifted radiation reflected from the foil surface. Special tests arranged to validate the origin of the satellites are described. The relative intensity of the reflected radiation compared with the direct radiation observed is at variance with the relative intensities reported for longer wavelengths. The reasons for this, possible effects of spectrometer geometry, and applications in the investigation or generation of polarization remain to be investigated
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 15; Aug. 197
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  • 46
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    Refractive-index profile and physical process determination in thick gratings in electrooptic crystals (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A method for determining the refractive index profile of thick phase gratings in linear electrooptic crystals is presented. This method also determines the effective photovoltaic electric field and the relative contributions of diffusion and drift during hologram recording. The method requires only a knowledge of the modulation ratio during hologram recording and the fundamental and the higher-order diffraction efficiencies of the grating. As an illustration of the method, the refractive index profile, the effective photovoltaic field, and the relative contributions of diffusion and drift are determined from experimental measurements for a lithium niobate holographic grating.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 15; Aug. 197
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  • 47
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    Oversampling of digitized images (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Oversampling is defined as sampling with a device whose characteristic width is greater than the interval between samples. This paper shows why oversampling should be avoided and discusses the limitations in data processing if circumstances dictate that oversampling cannot be circumvented. Principally, oversampling should not be used to provide interpolating data points. Rather, the time spent oversampling should be used to obtain more signal with less relative error, and the Sampling Theorem should be employed to provide any desired interpolated values. The concepts are applicable to single-element and multielement detectors.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Astronomical Journal; 81; Apr. 197
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  • 48
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    An alpha particle instrument with alpha, proton, and X-ray modes for planetary chemical analyses (1976)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The interaction of alpha particles with matter is employed in a compact instrument that could provide rather complete in-situ chemical analyses of surfaces and thin atmospheres of extraterrestrial bodies. The instrument is a miniaturized and improved version of the Surveyor lunar instrument. The backscattering of alpha particles and (alpha, p) reactions provide analytical data on the light elements (carbon-iron). An X-ray mode that detects the photons produced by the alpha sources provides sensitivity and resolution for the chemical elements heavier than about silicon. The X-rays are detected by semiconductor detectors having a resolution between 150 and 250 eV at 5.9 keV. Such an instrument can identify and determine with good accuracy 99 percent of the atoms (except hydrogen) in rocks. For many trace elements, the detecting sensitivity is a few ppm. Auxiliary sources could be used to enhance the sensitivities for elements of special interest. The instrument could probably withstand the acceleration involved in semi-hard landings.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Nuclear Instruments and Methods (ISSN 0167-5087); 134; 1976
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  • 49
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    Use of a multi-look unfocussed SAR processor on spacecraft (1976)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: Two methods of processing signals from a multi-look unfocussed synthetic-aperture radar are considered. A saving in the processor complexity is achieved in comparison to a fully focussed SAR system at the expense of slightly greater clutter levels and poorer along-track resolution. In addition, lower power consumption enables the unfocussed processor to increase the number of looks to compensate in part for the reduced resolution.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-156721 , RSL-TM-295-10
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    Advanced very high resolution radiometer (1976)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: The advanced very high resolution radiometer development program is considered. The program covered the design, construction, and test of a breadboard model, engineering model, protoflight model, mechanical structural model, and a life test model. Special bench test and calibration equipment was also developed for use on the program.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-156682
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    Evaluation of S-Band FM Direct Link Signal and System Design (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The adequacy of the S-band FM downlink as part of space shuttle orbiter communication links, was assessed to satisfy all known requirements during all mission phases. Some potential performance problems are described and corrective actions are recommended when appropriate.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-151584 , R7609-3
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    Frequency band justifications for passive sensors 10.0 to 385 GHz, chapter 1 (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: For abstract, see N78-15327.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-155530
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  • 53
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    Frequency band justifications for passive sensors 10.0 to 385 GHz, chapter 2 (1976)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: Sensitivity requirements of the various measurements obtained by microwave sensors, and radiometry techniques are described. Analytical techniques applied to detailed sharing analyses are discussed. A bibliography of publications pertinent to the scientific justification of frequency requirements for passive microwave remote sensing is included.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-155532
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    Frequency band justifications for passive sensors, 1 to 10 GHz (1976)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: Remote sensor systems operating in the microwave region of the frequency spectrum provide information unobtainable with basic imaging techniques such as photography, television, or multispectral imaging. The frequency allocation requirements for passive microwave sensors used in the earth exploration satellite and space research services are presented for: (1) agriculture, forestry, and range resources; (2) land use survey and mapping: (3) water resources; (4) weather and climate; (5) environmental quality; and (6) marine resources, estuarine and oceans. Because measurements are required simultaneously in multiple frequency bands to adequately determine values of some phenomena, the relationships between frequency bands are discussed. The various measurement accuracies, dynamic range, resolutions and frequency needs are examined. A band-by-band summary of requirements, unique aspects, and sharing analyses of the required frequency bands is included.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-155531
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    Radar systems for a polar mission, volume 3, appendices A-D, S, T (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Success is reported in the radar monitoring of such features of sea ice as concentration, floe size, leads and other water openings, drift, topographic features such as pressure ridges and hummocks, fractures, and a qualitative indication of age and thickness. Scatterometer measurements made north of Alaska show a good correlation with a scattering coefficient with apparent thickness as deduced from ice type analysis of stereo aerial photography. Indications are that frequencies from 9 GHz upward seem to be better for sea ice radar purposes than the information gathered at 0.4 GHz by a scatterometer. Some information indicates that 1 GHz is useful, but not as useful as higher frequencies. Either form of like-polarization can be used and it appears that cross-polarization may be more useful for thickness measurement. Resolution requirements have not been fully established, but most of the systems in use have had poorer resolution than 20 meters. The radar return from sea ice is found to be much different than that from lake ice. Methods to decrease side lobe levels of the Fresnel zone-plate processor and to decrease the memory requirements of a synthetic radar processor are discussed.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-156641 , RSL-TR-291-2-VOL-3
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    Microwave remote sensing of a two-layer random medium (1976)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: A two-variable expansion technique is used to solve for the mean Green's. function from the Dyson equation under the nonlinear approximation. The Bethe-Salpeter equation then gives rise to a set of modified radiative transfer (MRT) equations which accommodate coherent effects essential to bounded media. It is found that the nonlinear approximation, instead of the more popular bilocal approximation, should be used for the case of bounded media. The two approximations yield identical results for unbounded media. The MRT equations are then solved for a two-layer random medium. The MRT equations give rise to simple and useful solutions which are applicable to both active and passive microwave remote sensing.
    Keywords: COMMUNICATIONS AND RADAR
    Type: IEEE Transactions on Antennas and Propagation; AP-24; May 1976
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    Channel electron multipliers - Detection efficiencies with opaque MgF2 photocathodes at XUV wavelengths (1976)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Detection efficiencies of channel electron multipliers (CEM) with opaque MgF2 photocathodes obtained in the extreme ultraviolet (XUV), 44 A to 990 A, are reported. A stable highly efficient response is reported for that interval, with no adverse effects on CEM performance. Efficiencies twice those of uncoated CEMs are obtained for 50 A to 350 A. The Mullard B419BL and Galileo 4510WL single-stage cone-cathode CEMs were used in the experiments. A rare-gas double ionization chamber was employed as absolute standard detector for 406 A to 990 A, and a flow Geiger counter filled with 96% argon and 4% isobutane for 44 A to 256 A. Absolute detection efficiencies are 10% higher from 67 A to 990 A when photocathodes are illuminated at an angle of incidence 45 deg. The photocathodes suffered no loss of response in storage (in vacuum or air) after an initial aging period. Effects of scattered UV radiation are greatly reduced when MgF2-coated CEMs are used in the XUV.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 15; May 1976
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    A gated, wideband magnetic direction finder for lightning return strokes (1976)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: A magnetic direction finder has been developed which utilizes only the initial few microseconds of wideband return stroke waveforms to provide accurate directions to the channel bases of lightning discharges to ground. Bearing errors are minimized because, near the ground, most channels tend to be straight and vertical with no large branches or horizontal sections. Tests on a number of lightning storms at distances of 10 to 100 km indicate the angular resolution is in the range 1-2 deg, with little or no systematic dependence on azimuth or distance.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Applied Meteorology; 15; Mar. 197
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    Attenuation diversity measurements at 20 and 30 GHz (1976)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The results of data obtained at The University of Texas at Austin in conjunction with the ATS-6 millimeter wave experiment are presented. Attenuation measurements at 30 GHz and sky noise data at 20 GHz were obtained for 93 days simultaneously at each of two sites separated by 11 km and for 314 days at one site. The ratio of the loss at 30 GHz to that at 20 GHz due to rain varied from about 2 to about 4 with a median value of 2.65. This value was used to estimate 30 GHz losses for the 38.6% of time during attenuation events for which the satellite link was not available. Space diversity reduced outage time for a system in Austin, Texas, with a 10 db fade margin at 30 GHz from 3.8 hours to 4.1 minutes for the 93 days. Extrapolated to a yearly base this corresponds to 15 hours and to 16 minutes respectively. A plot of maximum observed cloud height against maximum hourly attenuation indicates that for a given attenuation level a lower limit is set for the maximum cloud height.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Radio Science; 11; Mar. 197
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    High-resolution imaging X-ray detector (1976)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The paper describes an X-ray detector using microchannel plates as a photocathode surface and imaging photoelectron multiplier, and a crossed wire grid as a two-dimensional position-sensitive detector. The position resolution is 10 microns. The crossed wire grid consists of 100-micron-diam wires on 200-micron centers. Position sensing is accomplished by electronic interpolation to 1/20 of the wire spacing. The quantum efficiency of the microchannel plates varies from 29% at 0.28 keV to 5% at 3 keV. This detector will provide second-of-arc X-ray imaging in the focal plane of the 342.9-cm focal length grazing-incidence telescope being prepared for the HEAO-B observatory. By addition of suitable photocathodes, it can be used for single-photon imaging light detection in the UV, visible, and near-IR-ranges. In all cases, it gives a very low dark counting rate, allows timing of individual events to 1 microsec or less, and can handle counting rates up to 10,000 per sec.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments; 47; Mar. 197
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  • 61
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    Pulsed resonance spectroscopy applied to turbulent combustion flows (1976)
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    Publication Date: 2019-06-27
    Description: The application of pulsed resonance spectroscopy to the measurement of species concentrations in chemically reacting turbulent flows is discussed. The theory of such measurements is developed. An uncertainty analysis is performed, and the results are applied to typical combustion conditions. Experimental aspects are discussed. The method shows a significant theoretical improvement in accuracy over Raman and Reyleigh scattering techniques, and no significant barriers appear to block its development.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 15; Apr. 197
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  • 62
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    Channel electron multiplier - Its quantum efficiency at soft X-ray and vacuum ultraviolet wavelengths (1976)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 15; Apr. 197
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    Wavelength dependence in radio-wave scattering and specular-point theory (1976)
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    Publication Date: 2019-06-27
    Description: Radio-wave scattering from natural surfaces contains a strong quasispecular component that at fixed wavelengths is consistent with specular-point theory, but often has a strong wavelength dependence that is not predicted by physical optics calculations under the usual limitations of specular-point models. Wavelength dependence can be introduced by a physical approximation that preserves the specular-point assumptions with respect to the radii of curvature of a fictitious, effective scattering surface obtained by smoothing the actual surface. A uniform low-pass filter model of the scattering process yields explicit results for the effective surface roughness versus wavelength. Interpretation of experimental results from planetary surfaces indicates that the asymptotic surface height spectral densities fall at least as fast as an inverse cube of spatial frequency. Asymptotic spectral densities for Mars and portions of the lunar surface evidently decrease more rapidly.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Radio Science; 11; Feb. 197
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    A very-long-baseline interferometer system for geodetic applications (1976)
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    Publication Date: 2019-06-27
    Description: A very-long-baseline interferometer system was designed and built for geodetic applications. Each interferometer terminal records a 360-kHz spectral band of noise from a compact extragalactic radio source. The center frequency of the spectral band can be selected to sample sequentially bands covering a much wider frequency range to obtain subnanosecond accuracy in group-delay measurements. A tunnel-diode pulse generator is used to calibrate the delays in the receiver. The necessary sets of algorithms and computer programs have been developed to analyze the data and have allowed the system to be employed to make accurate determinations of vector baselines, radio-source positions, polar motion, and universal time.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Radio Science; 11; May 1976
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    Sounder design considerations in the selection of temperature sensing channels (1976)
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    Publication Date: 2019-06-27
    Description: Simulation studies on the performance of IR sounders under varying conditions of cloud cover and cloud heights are carried out for Nimbus 6. An analytic function is derived for calculating the relative response to cloud height errors for arbitrary cloud-sensing channels. Based on the values of the response function, the best choice of channels for determining cloud amounts are obtained. An algorithm is described for determining cloud heights, and the sensitivity of cloud-height sensing channels is tested. It is found that for the HIRS instrument, the most transparent channel in the 4.3-micron band is optimal for adjusting cloud heights, while the channel in the 15-micron band peaking closest to the surface is best for determining cloud amounts
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Applied Meteorology; 15; Apr. 197
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    Computer analysis speeds corrugated horn design (1976)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: A computer analysis program is developed for selecting the optimum flare angle and horn length of a corrugated horn design, the horn diameter, and the radiation pattern, before resorting to machining operations. The calculated antenna pattern is best suited to narrowband designs, and averaging of the E and H planes is recommended for wideband work. The program language used is BASIC. Some design examples are provided with representative data, printouts, and a rundown of the equations programmed.
    Keywords: COMMUNICATIONS AND RADAR
    Type: MicroWaves; 15; May 1976
    Format: text
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    LaF3 infrared detector (1976)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: A class of infrared detectors is proposed, and experimental results are presented for a prototype device. The material used is LaF3, an ionic conductor with a capacitance that varies exponentially with temperature. The detectivity of a prototype detector is estimated from measured signal voltages and incident power, and a Johnson noise voltage is calculated from the measured resistance. At a modulation frequency of 20 Hz, the estimated detectivity is about 2 million cm/sq root Hz/W. For the parameters characterizing this device, the estimated detectivity is consistent with a theoretical prediction. The theory further predicts an optimum detectivity of about 1 billion cm/sq root Hz/W for much thinner devices than the prototypes.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Physics Letters; 28; June 1
    Format: text
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    Nonlinear dynamic theory for photorefractive phase hologram formation (1976)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: A nonlinear dynamic theory is developed for the formation of photorefractive volume phase holograms. A feedback mechanism existing between the photogenerated field and free-electron density, treated explicitly, yields the growth and saturation of the space-charge field in a time scale characterized by the coupling strength between them. The expression for the field reduces in the short-time limit to previous theories and approaches in the long-time limit the internal or photovoltaic field. Additionally, the phase of the space charge field is shown to be time-dependent.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Physics Letters; 28; Mar. 15
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    Sharing criteria and performance standards for the 11.7-12.2 GHz band in region 2 (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Possible criteria for sharing between the broadcasting-satellite and the fixed-satellite services are considered for each of several parameters in three categories: system, space station, and earth station. Criteria for sharing between the two satellite services and the three terrestrial services to which the 12-GHz band is allocated are discussed separately, first for the case of the fixed and mobile services and then for the broadcasting service.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-148756 , JPL-SP-43-35
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    Ballistic Signature Identification System Study (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The first phase of a research project directed toward development of a high speed automatic process to be used to match gun barrel signatures imparted to fired bullets was documented. An optical projection technique has been devised to produce and photograph a planar image of the entire signature, and the phototransparency produced is subjected to analysis using digital Fourier transform techniques. The success of this approach appears to be limited primarily by the accuracy of the photographic step since no significant processing limitations have been encountered.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-147820 , UNITECH-76-020-U
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    An analog technique for the measurement of damping from transient decay signals (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A tracking filter that includes an output that is logarithmically proportional to the amplitude of the filtered signal is used to measure the damping exponent of a transient decay. This method is analogous to the digital technique referred to as the moving-block or peak-plot method. The method is simple to use and quite accurate, avoids the numerical computations associated with similar digital techniques, but is constrained by the poor time-domain response characteristics of commercial tracking filters presently available.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-TM-X-73121 , A-6535
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    On the problem of embedding picture elements in regions (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A few new algorithms for region growing in pictures were developed. These algorithms are a step toward finding a satisfactory solution to the image segmentation problem, and in-depth understanding of the problems of nonsemantic image segmentation. The algorithms utilize a sequential decision approach for region boundaries detection. The sequential decisions are supported by a stochastic algorithm that maintains local statistics of the region near the boundaries as the region grows. A few illustrations of the algorithm's performance are included.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-148279 , JPL-TM-33-774
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    The application of an optical Fourier spectrum analyzer on detecting defects in mass-produced satellite photographs (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Various defects in mass-produced pictures transmitted to earth from a satellite are investigated. It is found that the following defects are readily detectable via Fourier spectrum analysis: (1) bit slip, (2) breakup causing loss of image, and (3) disabled track at the top of the imagery. The scratches made on the film during mass production, which are difficult to detect by visual observation, also show themselves readily in Fourier spectrum analysis. A relation is established between the number of scratches, their width and depth and the intensity of their Fourier spectra. Other defects that are found to be equally suitable for Fourier spectrum analysis or visual (image analysis) detection are synchronous loss without blurring of image, and density variation in gray scale. However, the Fourier spectrum analysis is found to be unsuitable for detection of such defects as pin holes, annotation error, synchronous loss with blurring of images, and missing image in the beginning of the work order. The design of an automated, real time system, which will reject defective films, is treated.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-148198
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    Computation of scalar far-field patterns of large-aperture antennas (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: In computer programs used for evaluating the performance of high-gain antennas, efficient numerical methods for calculating the far-field patterns must be used since the majority of computer time and storage requirements may be attributed to this phase of the program. The numerical method most frequently used is the Fast Fourier Transform (FFT), which computes the far field as the Fourier transform of the field distribution in the antenna aperture. A new numerical method that in many applications is superior to the FFT in terms of reducing computer time and storage requirements is described.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-TM-X-3408 , E-8746
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    Shuttle synthetic aperture radar implementation study, volume 1 (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Results of an implementation study for a synthetic aperture radar for the space shuttle orbiter are described. The overall effort was directed toward the determination of the feasibility and usefulness of a multifrequency, multipolarization imaging radar for the shuttle orbiter. The radar is intended for earth resource monitoring as well as oceanographic and marine studies.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-147775 , JPL-750-73-VOL-1
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    Program to design, fabricate, test, and deliver a thermal control-mixing control device for the George C. Marshall Space Flight Center (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The development and testing of a temperature sensor and pulse duration modulation (PDM) diverter valve for a thermal control-mixing control device are described. The temperature sensor selected for use uses a fluidic pin amplifier in conjunction with an expansion device. This device can sense changes of less than 0.25 F with greater than 15:1 signal to noise ratio when operating with a typical Freon pump supplied pressure. The pressure sensitivity of the sensor is approximately 0.0019 F/kPa. The valve which was selected was tested and performed with 100% flow diversion. In addition, the valve operates with a flow efficiency of at least 95%, with the possibility of attaining 100% if the vent flow of the PDM can be channeled through the last stage of the diverter valve. A temperature sensor which utilized an orifice bridge circuit and proportional-vortex combination mixing valve were also evaluated, but the concepts were rejected due to various problems.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-144327 , AIRESEARCH-76-411348(1)
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    Microelectronic bioinstrumentation systems (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Progress was made in the development of an RF cage, a single channel RF powered ECG telemetry system, and a three channel RF powered ECG, aortic blood pressure, and body temperature telemetry system. Encapsulation materials for chronic implantation of electronic circuits in the body were also evaluated.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-148145
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    Development of a drive system for a sequential space camera (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Breadboard models of single and dual motor drives for the shutter, claw and magazine of a space camera system were designed and tested. The single motor technique utilizes a single electronically commutated motor to drive the claw and shutter without resorting to a solenoid actuated clutch for pulse operation. Shutter speed is established by a combination of the cinemode speed and the opening of the conventional DAC two piece shutter. Pulse mode operation is obtained by applying power at a fixed clock rate and removing power at an appropriate point in the mechanical cycle such that the motor comes to rest by system friction. The dual motor approach utilizes a stepper motor to drive the shutter and an electronically commutated dc motor to drive the claw and magazine functions. The motors are synchronized electronically.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-147759 , SPO-30352-ADD
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    Payload operation television system (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The Payload Operation Television System is a high performance closed-circuit TV system designed to determine the feasibility of using TV to augment purely visual monitoring of operations, and to establish optimum system design of an operating unit which can ultimately be used to assist the operator of a remotely manipulated space-borne cargo loading device. The TV system assembled on this program is intended for laboratory experimentation which would develop operational techniques and lead to the design of space-borne TV equipment whose purpose would be to assist the astronaut-operator aboard a space station to load payload components. The equipment consists principally of a good quality TV camera capable of high resolving power; a TV monitor; a sync generator for driving camera and monitor; and two pan/tilt units which are remotely controlled by the operator.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-147777
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    Communications and tracking subsystem approach and landing test phase task 501 RF path console acceptance test report (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The RF downlink S-band path in the RF path console was tested under quality assurance inspection. The UHF RF paths were also tested. The acceptance test plans, procedures, and results of the acceptance tests are included.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-147764 , LEC-8634 , JSC-11194
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    Design document for shuttle task 501. Shuttle carrier aircraft transceiver console (SED 36115353-301) (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The flight data for the space shuttle orbiter (SSO) is transmitted via S band to a transceiver in the shuttle carrier aircraft (SCA) for relay to the ground during the mated portion of the approach and landing test (ALT). The transceiver is mounted in the SCA transceiver console for shuttle task 501 testing. This document defines the requirements for the SCA transceiver console, the design description, test plan for the console prior to installating the spacecraft equipment in the console, and the test plan for acceptance tests.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-147765 , JSC-11086 , LEC-8246
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    Shuttle spectrum despreader (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The results of the spread spectrum despreader project are reported and three principal products are designed and tested. The products are, (1) a spread spectrum despreader breadboard, (2) associated test equipment consisting of a spectrum spreader and bit reconstruction/error counter and (3) paper design of a Ku-band receiver which would incorporate the despreader as a principal subsystem. The despreader and test set are designed for maximum flexibility. A choice of unbalanced quadriphase or biphase shift keyed data modulation is available. Selectable integration time and threshold voltages on the despreader further lend true usefulness as laboratory test equipment to the delivered hardware.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-147749 , TRW-28453 , CDRL-0002
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  • 83
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    Analysis of aircraft wing-mounted antenna patterns (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: High frequency radiation patterns of aircraft wing mounted antennas are analyzed. Basic antenna types using ray optical techniques are studied. The aircraft is modelled in its most basic form so that this study is applicable to general type aircraft. The fuselage is modelled as a perfectly conducting finite elliptic cylinder. The wings and horizontal and vertical stabilizers are modelled as perfectly conducting "n" sided flat plates that can be arbitrarily attached to the fuselage or to themselves. The antenna locations are assumed to be on the surfaces of the wings at locations removed from engines and stores such that these effects are negligible. Volumetric patterns are calculated for several aircraft. The validity of the solution is shown by comparing the results against scale model measurements. The application of this solution to practical airborne antenna problems has shown its versatility in designing antennas and predicting their radiation patterns in an accurate and efficient manner.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-148199 , TR-2902-25
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    Readout electrode assembly for measuring biological impedance (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The invention comprises of a pair of readout ring electrodes which are used in conjunction with apparatus for measuring the electrical impedance between different points in the body of a living animal to determine the amount of blood flow therebetween. The readout electrodes have independently adjustable diameters to permit attachment around different parts of the body between which it is desired to measure electric impedance. The axial spacing between the electrodes is adjusted by a pair of rods which have a first pair of ends fixedly attached to one electrode and a second pair of ends slidably attached to the other electrode. Indicia are provided on the outer surface of the ring electrodes and on the surface of the rods to permit measurement of the circumference and spacing between the ring electrodes.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
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    A transformation method for deriving from a photograph, position and heading of a vehicle in a plane (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Equations have been derived that transform perspectively viewed planar surface coordinates, as seen in a photograph, into coordinates of the original plane surface. These transformation equations are developed in terms of nine geometric variables that define the photographic setup and are redefined in terms of eight parameters. The parameters are then treated as independent quantities that fully characterize the transformation and are expressed directly in terms of the four corner coordinates of a reference rectangle in the object plane and their coordinates as seen in a photograph. Vehicle position is determined by transforming the perspectively viewed coordinate position of a representative vehicle target into runway coordinates. Vehicle heading is determined from the runway coordinates of two vehicle target points. When the targets are elevated above the plane of the reference grid, the computation of the heading angle is unaffected; however, the computation of the target position may require adjustment of two parameters. Methods are given for adjusting the parameters for elevation and an example is included for both nonelevated and elevated target conditions.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-TN-D-8201 , L-10411
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    High-resolution surface temperature measurements on rotating turbine blades with an infrared pyrometer (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A high-resolution pyrometer was developed and tested on a modified turbine engine. The pyrometer was used to obtain temperature profiles of the viewed surface of turbine blades in the engine at tip speeds up to 366 meters per second. The combination of coherent fiber optics, a silicon avalanche detector, and high-speed electronics enabled surface resolution of a spot diameter of 0.05 centimeter. The data, in the form of temperature profiles, was obtained in near real time as a hard copy output from a computer display terminal. Temperatures measured with the pyrometer and with thermocouples agreed within 2 percent at temperatures between 977 to 1144 K.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-TN-D-8213 , E-8613
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    Volumetric pattern analysis of fuselage-mounted airborne antennas (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A volumetric pattern analysis of fuselage-mounted airborne antennas at high frequencies was investigated. The primary goal of the investigation was to develop a numerical solution for predicting radiation patterns of airborne antennas in an accurate and efficient manner. An analytical study of airborne antenna pattern problems is presented in which the antenna is mounted on the fuselage near the top or bottom. Since this is a study of general-type commercial aircraft, the aircraft was modeled in its most basic form. The fuselage was assumed to be an infinitely long perfectly conducting elliptic cylinder in its cross-section and a composite elliptic cylinder in its elevation profile. The wing, cockpit, stabilizers (horizontal and vertical) and landing gear are modeled by "N" sided bent or flat plates which can be arbitrarily attached to the fuselage. The volumetric solution developed utilizes two elliptic cylinders, namely, the roll plane and elevation plane models to approximate the principal surface profile (longitudinal and transverse) at the antenna location. With the belt concept and the aid of appropriate coordinate system transformations the solution can be used to predict the volumetric patterns of airborne antennas in an accurate and efficient manner. Applications of this solution to various airborne antenna problems show good agreement with scale model measurements. Extensive data are presented for a microwave landing antenna system.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-147099 , TR-2902-24
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    Ku band low noise parametric amplifier (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A low noise, K sub u-band, parametric amplifier (paramp) was developed. The unit is a spacecraft-qualifiable, prototype, parametric amplifier for eventual application in the shuttle orbiter. The amplifier was required to have a noise temperature of less than 150 K. A noise temperature of less than 120 K at a gain level of 17 db was achieved. A 3-db bandwidth in excess of 350 MHz was attained, while deviation from phase linearity of about + or - 1 degree over 50 MHz was achieved. The paramp operates within specification over an ambient temperature range of -5 C to +50 C. The performance requirements and the operation of the K sub u-band parametric amplifier system are described. The final test results are also given.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-147560 , C362-1
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    Laser velocimetry applied to transonic and supersonic aerodynamics (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Measurements obtained with laser velocimetry in a Mach 2.9 separated turbulent boundary layer and in the transonic flow past a two-dimensional airfoil section are presented and compared to data realized by conventional techniques. Agreement in mean velocities was realized where the pressure measurements could be considered reliable; however, in regions of instantaneous reverse velocities, the laser results were found to be consistent with the physics of the flow whereas the pressure data were not. Streamwise turbulence intensities are also presented. In the transonic airfoil study, velocity measurements obtained immediately outside the upper surface boundary layer of a 6-inch chord NACA 64A010 airfoil are compared to edge velocities inferred from surface pressure measurements. For free-stream Mach numbers of 0.6 and 0.8, the agreement in results was very good. "Dual scatter" optical arrangements in conjunction with a single particle, counter-type signal processor were employed in these investigations.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-TM-X-73117 , A-6510
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  • 90
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    Comparison of rate one-half, equivalent constraint length 24, binary convolutional codes for use with sequential decoding on the deep-space channel (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Virtually all previously-suggested rate 1/2 binary convolutional codes with KE = 24 are compared. Their distance properties are given; and their performance, both in computation and in error probability, with sequential decoding on the deep-space channel is determined by simulation. Recommendations are made both for the choice of a specific KE = 24 code as well as for codes to be included in future coding standards for the deep-space channel. A new result given in this report is a method for determining the statistical significance of error probability data when the error probability is so small that it is not feasible to perform enough decoding simulations to obtain more than a very small number of decoding errors.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-146846 , EE-762
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  • 91
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    Payload operation television system (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The TV system assembled is intended for laboratory experimentation which would develop operational techniques and lead to the design of space-borne TV equipment whose purpose would be to assist the astronaut-operator aboard a space station to load payload components. The TV system assembled for this program is a black and white, monocular, high performance system. The equipment consists principally of a good quality TV camera capable of high resolving power; a TV monitor; a sync generator for driving camera and monitor; and two pan/tilt units which are remotely controlled by the operator. One pan/tilt unit provides control of the pointing of the camera, the other similarly controls the position of a simulated payload.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-147534
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    A global search and rescue concept using synthetic aperture radar and passive user targets (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A terrestrial search and rescue concept is defined embodying the use of passive radio-frequency reflectors in conjunction with an orbiting synthetic aperture radar to detect, identify, and locate users. An airborne radar test was conducted to evaluate the basic concept. In this test simple corner-reflector targets were successfully imaged. Results from this investigation were positive and indicate that the concept can be used to investigate new approaches focused on the development of a global search and rescue system.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-TN-D-8172 , L-10259
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    Filtering device (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An electrical filter for removing noise from a voice communications signal is reported; seven sample values of the signal are obtained continuously, updated and subjected to filtering. Filtering is accomplished by adding balanced, with respect to a mid-point sample, spaced pairs of the sampled values, and then multiplying each pair by a selected filter constant. The signal products thus obtained are summed to provide a filtered version of the original signal.
    Keywords: COMMUNICATIONS AND RADAR
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    Highly efficient antenna system using a corrugated horn and scanning hyperbolic reflector (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: In a horn-reflector antenna system for producing a spherical aperture phase front, a corrugated conical horn illuminates a section of a hyperbolic reflector to produce a spherical aperture phase front. This front produces a far field beam with low sidelobes and high beam efficiency. The system is insensitive to frequency and polarization changes, and is also insensitive to orientation about the axis of the conical horn for beam scanning.
    Keywords: COMMUNICATIONS AND RADAR
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    Advanced prototype automated iodine monitor system (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The technique of detecting and measuring parts-per-million concentrations of aqueous iodine by direct spectrophotometric means is discussed, and development of a prototype Automated Iodine Monitoring/Controller System (AIMS) is elaborated. The present effort is directed primarily toward reducing the power requirement and the weight of the AIMS. Other objectives include determining the maximum concentration of iodine that can be dissolved in an alcohol solution, and in an aqueous potassium iodide solution. Also discussed are the effects of a no flow condition on iodine measurements and the effect of pH on spectrophotometric iodine determinations.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-147492 , FR-1203-101
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    Study of low frequency hydromagnetic waves using ATS-1 data (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Low frequency oscillations of the magnetic field at ATS-1 were analyzed for the 25 month data interval, Dec., 1966 through 1968. Irregular oscillations and those associated with magnetic storms were excluded from the analysis. Of the 222 events identified, 170 were found to be oscillating predominantly transverse to the background magnetic field. The oscillations were observed to occur most frequently in the early afternoon hours. They also seemed to occur more frequently during Dec., Jan., and Feb. than at any other time of the year. During a given event, the frequency was fairly constant. The event duration varied between a minimum of 10 min. and a maximum of 14 hrs and 26 min. During a given event the amplitude varied.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-148580
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  • 97
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    Study to investigate and evaluate means of optimizing the radar function for the space shuttle (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A detailed analysis of the spiral scan was performed for antenna sizes ranging from 20 inches to 36 inches in diameter and for search angles characteristic of both the radar and the communication acquisition modes. The power budgets for passive target radar detection were calculated for antenna diameters ranging from 20 to 36 inches. Dwell times commensurate with spiral scan were used for these budget calculations. The signal design for the candidate pulse Doppler system is summarized. Ground return analysis carried out for the passive target radar mode is examined, and the details are presented. A concluding description of the proposed candidate radar/communication system configuration is given.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-147842 , R7607-4
    Format: application/pdf
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  • 98
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    Unknown
    KIM-1 interface adapter to 3-wire teletype systems (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The KIM-1 circuit designed for use with a full duplex isolated 4 terminal system is described. Operation of the circuit with a 3 wire system in conjunction with a single +5v supply interface is discussed.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-148768 , TM-38
    Format: application/pdf
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  • 99
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    Unknown
    Detector absorptivity measuring method and apparatus (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A method and apparatus for measuring the absorptivity of a radiation detector by making the detector an integral part of a cavity radiometer are described. By substituting the detector for the surface of the cavity upon which the radiation first impinges a comparison is made between the quantity of radiation incident upon the detector and the quantity reflected from the detector. The difference between the two is a measurement of the amount of radiation absorbed by the detector.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 100
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    Unknown
    Sun angle calculator (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A circular computer and system is disclosed for determining the sun angle relative to the horizon from any given place and at any time. The computer includes transparent, rotatably mounted discs on both sides of the circular disc member. Printed on one side of the circular disc member are outer and inner circular sets of indicia respectively representative of site longitude and Greenwich Mean Time. Printed on an associated one of the rotatable discs is a set of indicia representative of Solar Time. Printed on the other side of the circular disc member are parallel lines representative of latitude between diametral representations of North and South poles. Elliptical lines extending between the North and South poles are proportionally disposed on the surface to scale Solar Time in hours.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Format: application/pdf
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    NASA TECHNICAL REPORTS
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