ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • COMMUNICATIONS AND RADAR  (237)
  • 1995-1999
  • 1980-1984
  • 1975-1979  (237)
  • 1940-1944
  • 1977  (237)
Sammlung
Schlagwörter
Erscheinungszeitraum
  • 1995-1999
  • 1980-1984
  • 1975-1979  (237)
  • 1940-1944
Jahr
  • 101
    facet.materialart.
    Unbekannt
    On the maximum off-axis gain of symmetrical pencil-beam antennas (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: For a general class of symmetrical pencil-beam antennas, the gain at a given off-axis angle can be maximized by choosing the proper antenna size. The maximum gain at the given angle relative to the on-axis gain is independent of the given angle and dependent only on the main-beam pattern. It is computed here for four commonly used gain functions. Its value, in all cases, is close to 4 dB. This result is important in the definition of service areas for communication and broadcast satellites.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Antennas and Propagation; AP-25; May 1977
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 102
    facet.materialart.
    Unbekannt
    Limiter-discriminator detection performance of Manchester and NRZ coded FSK (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The theory of limiter-discriminator detection of a frequency shift keyed (FSK) carrier is reviewed and this theory is used to predict the bit error probability performance of Manchester coded and nonreturn-to-zero (NRZ) coded data. A major result of the study is that the predetection time bandwidth product BT and the deviation ratio h needed to give optimum performance for Manchester coding are seen to be larger than optimum NRZ FSK. Specifically, BT of about 2 and h of about 1 will result in Manchester performance about 2 dB worse than optimum NRZ.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Aerospace and Electronic Systems; AES-13; Jan. 197
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 103
    facet.materialart.
    Unbekannt
    Speech analyzer (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A speech signal is analyzed by applying the signal to formant filters which derive first, second and third signals respectively representing the frequency of the speech waveform in the first, second and third formants. A first pulse train having approximately a pulse rate representing the average frequency of the first formant is derived; second and third pulse trains having pulse rates respectively representing zero crossings of the second and third formants are derived. The first formant pulse train is derived by establishing N signal level bands, where N is an integer at least equal to two. Adjacent ones of the signal bands have common boundaries, each of which is a predetermined percentage of the peak level of a complete cycle of the speech waveform.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 104
    facet.materialart.
    Unbekannt
    TDRSS telecommunication system PN code analysis (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The pseudonoise (PN) code library for the Tracking and Data Relay Satellite System (TDRSS) Services was defined and described. The code library was chosen to minimize user transponder hardware requirements and optimize system performance. Special precautions were taken to insure sufficient code phase separation to minimize cross-correlation sidelobes, and to avoid the generation of spurious code components which would interfere with system performance.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-152580
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 105
    facet.materialart.
    Unbekannt
    Orbiter CCTV video signal noise analysis (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The amount of steady state and transient noise which will couple to orbiter CCTV video signal wiring is predicted. The primary emphasis is on the interim system, however, some predictions are made concerning the operational system wiring in the cabin area. Noise sources considered are RF fields from on board transmitters, precipitation static, induced lightning currents, and induced noise from adjacent wiring. The most significant source is noise coupled to video circuits from associated circuits in common connectors. Video signal crosstalk is the primary cause of steady state interference, and mechanically switched control functions cause the largest induced transients.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-151479 , REPT-1.3-DN-C0704-039
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 106
    facet.materialart.
    Unbekannt
    Monopulse receiver (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A time division multiplexing and a quadraphase combining dual channel system were analyzed, designed, and tested. Analyses performed include the following: (1) boresight error as a function of the error channel bandwidth; (2) error channel interference with the sum channel functions; (3) threshold performance; and (4) error channel crosstalk, linearity, and drift as a function of signal level, Doppler, and environment. Test results indicate that the time division multiplexing system meets the design goals of the program. However, careful selection and alignment of all gain controlled amplifiers are required along with temperature compensation of the angle channel gain. The quadraphase system crosstalk performance is comparatively poor (-15 dB) with respect to the -30 dB requirements and this consequently affects gain tracking performance. Gain tracking was found to be + or - 20 percent rather than the + or - 5 percent specification. Data for the two systems is compared and recommendations are presented.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-153910
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 107
    facet.materialart.
    Unbekannt
    Theoretical aspects of sounder antenna operation (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The fundamental problem of calculating the radiation from an electric dipole immersed in a magnetoplasma is one of solving Maxwell's equations coupled to the self-consistent field-particle equations describing the plasma. For very small applied antenna voltages, the plasma dynamics may be linearized, and the plasma reaction currents computed self-consistently in terms of the voltage on the antenna. Thus, the short dipole can be idealized as a point dipole of moment P sub o = C sub a, V sub o el, where C sub a is the antenna element-to-plasma capacitance for a sheath of dimensions roughly several plasma Debye lengths and el is the dipole element's length. In actual practice, it is at this point that the first difficulty with the antenna theory arises. Even for small signals, the sheath around such an antenna will exhibit a complex impedance. For larger signals, nonlinear effects appear. Attemps are made to solve this problem.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Final Rept. on Tech. Work Accomplished under contract NASw-2953; 12 p
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 108
    facet.materialart.
    Unbekannt
    Three-dimensional ion sound turbulence (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A fast cold large diameter electron beam is injected into a uniform background plasma. The injected beam current is balanced by a field-aligned return current which gives rise to an ion acoustic instability. The plasma is essentially unbounded and collisionless on the time scale of the pulsed experiment. The fluctuations are analyzed by probe techniques in real time and space as well as in the frequency and wavenumber domains. Strong density fluctuations are observed in the entire ion acoustic spectrum reaching peak amplitudes at the low frequency end. The propagation of phase coherent test waves in the current carrying plasma is investigated. For the highly turbulent regime strong damping is observed while at lower drift velocities direction is observed. Oblique propagation of two strong test waves at different frequencies indicate the role of nonlinear ion Landau damping in absorption of wave energy.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Final Report. on Tech. Work Accomplished under contract NASw-2953; 51 p
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 109
    facet.materialart.
    Unbekannt
    Current-limited electron beam injection (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The injection of an electron beam into a weakly collisional, magnetized background plasma was investigated experimentally. The injected beam was energetic and cold, the background plasma was initially isothermal. Beam and plasma dimensions were so large that the system was considered unbounded. The temporal and spatial evolution of the beam-plasma system was dominated by collective effects. High-frequency electrostatic instabilities rapidly thermalized the beam and heated the background electrons. The injected beam current was balanced by a return current consisting of background electrons drifting toward the beam source. The drift between electrons and ions gave rise to an ion acoustic instability which developed into strong three-dimensional turbulence. It was shown that the injected beam current was limited by the return current which is approximately given by the electron saturation current. Non-Maxwellian electron distribution functions were observed.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Final Rept. on Tech. Work Accomplished under contract NASw-2953; 31 p
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 110
    facet.materialart.
    Unbekannt
    Scattering in discrete random media with implications to propagation through rain (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The multiple scattering effects on wave propagation through a volume of discrete scatterers were investigated. The mean field and intensity for a distribution of scatterers was developed using a discrete random media formulation, and second order series expansions for the mean field and total intensity derived for one-dimensional and three-dimensional configurations. The volume distribution results were shown to proceed directly from the one-dimensional results. The multiple scattering intensity expansion was compared to the classical single scattering intensity and the classical result was found to represent only the first three terms in the total intensity expansion. The Foldy approximation to the mean field was applied to develop the coherent intensity, and was found to exactly represent all coherent terms of the total intensity.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-TM-X-71352 , X-953-77-131
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 111
    facet.materialart.
    Unbekannt
    Measurements of AAFE RADSCAT antenna characteristics (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Antenna characteristics (active and passive) for a modified AAFE-RADSCAT parabolic dish antenna are documented for a variety of antenna configurations. The modified antenna was a replacement for the original unit which was damaged in January 1975. Pattern measurements made at Langley Research Center and Johnson Space Center are presented, with an analysis of the results. Antenna loss measurements are also presented and summarized.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-TM-X-72844
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 112
    facet.materialart.
    Unbekannt
    Oblique whistler instabilities (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The predicted instability of obliquely propagating whistler waves in a plasma penetrated by an electron beam is verified in a laboratory experiment. The observations support the model for the generation of auroral hiss and compare favorably with ground and satellite observations of VLF hiss. In contrast to the conventional small-diameter laboratory beam-plasma systems the device used is large compared to the characteristic whistler wavelength. Unstable whistlers can therefore, propagate and grow oblique to the beam over many wavelengths before encountering the plasma boundaries.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Final Report on Tech. Work Accomplished under contract NASw-2953; 44 p
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 113
    facet.materialart.
    Unbekannt
    Ku-band signal design study (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The acquisition/tracking performance of a practical squaring loop in which the times two multiplier is mechanized as a limiter/multiplier combination is evaluated. This squaring approach serves to produce the absolute value of the arriving signal as opposed to the perfect square law action which is required in order to render acquisition and tracking performance equivalent to that of a Costas loop. The Ku-Band orbiter signal design for the forward link is assessed. Acquisition time results and acquisition and tracking thresholds are summarized. A tradeoff study which pertains to bit synchronization techniques for the high rate Ku-Band channel is included and an optimum selection is made based upon the appropriate design constraints.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-151348 , TR-04-7604-6
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 114
    facet.materialart.
    Unbekannt
    Poor-resolution satellite observations of radar return from North America, Brazil, and the oceans (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The 13.9 GHz radar scatterometer on Skylab produced statistics of radar returns from thousands of points in North America and Brazil, as well as from the oceans. The resolution cell of the system varied from about 11 km in diameter at vertical incidence to 20 by 30 km at 50 deg incidence. Although these cells are larger than the preprocessing cells to be expected from spacecraft synthetic-aperture radars, they are at least as comparable with such cells as are the observation cells when aircraft radars are used. Results are presented both in terms of composite statistics for North America, Brazil, and the oceans, and in terms of statistics for particular classes of terrain. Both vertical and horizontal polarization data are presented for the land, and cross-polarized measurements are presented as well as for the sea. Correlations are indicated for the returns at different angles and polarizations.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: AGARD New Devices, Tech. and Systems in Radar; 19 p
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 115
    facet.materialart.
    Unbekannt
    A simple technique for high resolution time domain phase noise measurement (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A new time domain phase comparator is described. The device uses a novel technique to allow time domain phase measurements to be made with period and time interval counters without the use of offset reference oscillators. The device uses a single reference oscillator and allows measurements with a phase resolution greater than the noise floor of the reference. Data is presented showing a phase resolution of 0.02ps at 5 MHz with a crystal reference. The device has application in measuring the phase stability of systems where approximate phase quadrature can be maintained.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-TM-X-71300 , X-814-77-43 , NASA/DOD PTTI Planning Meeting
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 116
    facet.materialart.
    Unbekannt
    Analysis of transmission error effects on the transfer of real-time simulation data (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: An analysis was made to determine the effect of transmission errors on the quality of data transferred from the Terminal Area Air Traffic Model to a remote site. Data formating schemes feasible within the operational constraints of the data link were proposed and their susceptibility to both random bit error and to noise burst were investigated. It was shown that satisfactory reliability is achieved by a scheme formating the simulation output into three data blocks which has the priority data triply redundant in the first block in addition to having a retransmission priority on that first block when it is received in error.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-TM-X-74019
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 117
    facet.materialart.
    Unbekannt
    Method of locating persons in distress (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A method for locating any person in distress in a selected area on the surface of the earth who has deployed passive radio frequency (RF) reflectors in a predetermined arrangement is analyzed. A first transparency is made in the spatial frequency domain of an image of said predetermined arrangement of said RF reflectors. The said selected area of the surface of the earth is scanned by means of a side-looking radar, on board a satellite or aircraft, to produce radar images. Second transparencies in the conventional image domain are produced from the radar images. It is then determined from the first and second transparencies, by means of complex spatial filtering.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 118
    facet.materialart.
    Unbekannt
    Multiple rate digital command detection system with range clean-up capability (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A multi-rate digital command system is disclosed which uses the composite signal of a mu-type ranging system as a subcarrier to transmit range codes and data from a station to a receiver where the range codes are sequentially phase modulated on a subcarrier of frequency by one of its own subharmonics and data is phase modulated on a selected ranging component. A range cleanup loop in a spacecraft locks the phase of a locally generated reference component to a received ranging component and retransmits the component to a ground station. When the inverse phase of a ranging component is received and detected, the cleanup loop is modified to demodulate phase modulated command symbols while continuing tracking the same ranging component. The command symbol rate is coherently related to the ranging signal component bit rate.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 119
    facet.materialart.
    Unbekannt
    A new series representation for the radiation integral with application to reflector antennas (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Antennas and Propagation; AP-25; Sept
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 120
    facet.materialart.
    Unbekannt
    An analysis of the Wheeler method for measuring the radiating efficiency of antennas (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A model problem is formulated to evaluate the limitations imposed by the assumptions in the Wheeler or cap method for measuring the radiating efficiency of antennas. The antenna in the model is a circular loop and the radiation shield is a spherical metal shell. Calculated values of the actual efficiency of the antenna and the efficiency that would be measured using the Wheeler method are compared to determine the accuracy of the method and set guidelines for its application.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Antennas and Propagation; AP-25; July 197
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 121
    facet.materialart.
    Unbekannt
    A unified analysis of pseudonoise synchronization by envelope correlation (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A relationship between coarse acquisition (coarse alignment of two pseudonoise codes to within approximately one code symbol) and fine acquisition (tracking) in a pseudonoise modulated spread spectrum communication system is studied. A convenient technique for determining mean acquisition time and hold-in time (mean time to lose lock) after acquisition, using a delay lock loop, is elaborated. An analysis procedure for handling the transition from search to lock is developed and applied to a problem containing representative Space Shuttle data (signal parameters and synchronizer parameters).
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Communications; COM-25; Aug. 197
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 122
    facet.materialart.
    Unbekannt
    Digital technique for generating synthetic aperture radar images (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: This paper describes a digital processing method applicable to a synthetic aperture radar, to be carried by the space shuttle or by satellites. The method uses an earth-fixed coordinate system in which corrective procedures are invoked to compensate for errors introduced by the satellite motion, earth curvature, and wavefront curvature. Among the compensations discussed are those of the coordinate system, skewness, roll, pitch, yaw, earth rotation, and others. The application of a Fast Fourier Transform in the numerical processing of the two-dimensional convolution is discussed in detail.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IBM Journal of Research and Development; 21; Sept
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 123
    facet.materialart.
    Unbekannt
    ATS-6 ascending: Near horizon measurements over water at 30 GHz (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The return of the ATS 6 satellite to a western longitude during the fall of 1976 presented a unique opportunity to perform low angle of elevation measurements at 30 GHz. For this purpose a receiver using a 1.5 m antenna was set up at Port Aransas, Texas, resulting in a propagation path entirely over water. The 30 GHz beacon was monitored daily for at least one hour from 8 September 1976 to 21 September 1976. During the time the elevation angle changed from 1.5 deg to 17.3 deg, the mean attenuation decreased from 20 dB to 2 dB and the standard deviation from over 6 dB to less than .2 dB. The deep fades at angles below 4 deg show significantly sharper nulls than peaks on a log scale. Spectra of the log amplitude fluctuations vary as the (-8/3) power of the spectral frequency in the limit. A flattening is noticeable at the low frequencies. A precipitation event at 8.5 deg elevation produced a 16 dB fade and significantly increased the variance.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-159966 , URSI Comm. of Open Symp. on Propagation in Nonionized Media; Apr 28, 1977 - May 06, 1977; LaBaule; France
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 124
    facet.materialart.
    Unbekannt
    Aircraft measurement of radio frequency noise at 121.5 MHz, 243MHz and 406MHz (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: An airborne survey measurement of terrestrial radio-frequency noise over U.S. metropolitan areas has been made at 121.5, 243 and 406 MHz with horizontal-polarization monopole antennas. Flights were at 25,000 feet altitude during the period from December 30, 1976 to January 8, 1977. Radio-noise measurements, expressed in equivalent antenna-noise temperature, indicate a steady-background noise temperature of 572,000 K, at 121.5 MHz, during daylight over New York City. This data is helpful in compiling radio-noise temperature maps; in turn useful for designing satellite-aided, emergency-distress search and rescue communication systems.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Symposium and Technical Exhibition; Jun 28, 1977 - Jun 30, 1977; Montreux; Switzerland
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 125
    facet.materialart.
    Unbekannt
    The proposed coding standard at GSFC (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: As part of the continuing effort to introduce standardization of spacecraft and ground equipment in satellite systems, NASA's Goddard Space Flight Center and other NASA facilities have supported the development of a set of standards for the use of error control coding in telemetry subsystems. These standards are intended to ensure compatibility between spacecraft and ground encoding equipment, while allowing sufficient flexibility to meet all anticipated mission requirements. The standards which have been developed to date cover the application of block codes in error detection and error correction modes, as well as short and long constraint length convolutional codes decoded via the Viterbi and sequential decoding algorithms, respectively. Included are detailed specifications of the codes, and their implementation. Current effort is directed toward the development of standards covering channels with burst noise characteristics, channels with feedback, and code concatenation.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: EASCON-77; Electronics and Aerospace Systems Convention; Sep 26, 1977 - Sep 28, 1977; Arlington, VA
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 126
    facet.materialart.
    Unbekannt
    Public Service Communication Satellite Program (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The proposed NASA Public Service Communication Satellite Program consists of four different activities designed to fulfill the needs of public service sector. These are: interaction with the users, experimentation with existing satellites, development of a limited capability satellite for the earliest possible launch, and initiation of an R&D program to develop the greatly increased capability that future systems will require. This paper will discuss NASA efforts in each of these areas.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: EASCON-77; Electronics and Aerospace Systems Convention; Sep 26, 1977 - Sep 28, 1977; Arlington, VA
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 127
    facet.materialart.
    Unbekannt
    Communication satellite services for special purpose users (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The present study identifies potential satellite services, examines the technology necessary for efficient implementation of these services, and determines minimum service cost versus user network size. The generic satellite services evaluated comprise TV and radio distribution (for retransmission), video teleconferencing (interactive), audio/facsimile teleconferencing (interactive), multiplexed data/voice (point-to-point), and satellite-supported land mobile. Satellite costs are based on extrapolations from ongoing commercial satellite programs. Production methods, new technology, and effect of production quantities on present and future production costs are examined to provide information on earth station equipment cost versus the variable 'buy'. Six different launch vehicles from a Delta 2914 to a dedicated Shuttle and three frequency bands and both broadcast (no eclipse capability) and fixed service satellites are considered to assess the effect of satellite size on cost and performance. It is assumed that the user pays only for his prorata share of the space segment costs.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Intelcom ''77 Symposium; Oct 09, 1977 - Oct 15, 1977; Atlanta, GA
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 128
    facet.materialart.
    Unbekannt
    Low cost Ku-band earth terminals for voice/data/facsimile (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: A Ku-band satellite earth terminal capable of providing two way voice/facsimile teleconferencing, 128 Kbps data, telephone, and high-speed imagery services is proposed. Optimized terminal cost and configuration are presented as a function of FDMA and TDMA approaches to multiple access. The entire terminal from the antenna to microphones, speakers and facsimile equipment is considered. Component cost versus performance has been projected as a function of size of the procurement and predicted hardware innovations and production techniques through 1985. The lowest cost combinations of components has been determined in a computer optimization algorithm. The system requirements including terminal EIRP and G/T, satellite size, power per spacecraft transponder, satellite antenna characteristics, and link propagation outage were selected using a computerized system cost/performance optimization algorithm. System cost and terminal cost and performance requirements are presented as a function of the size of a nationwide U.S. network. Service costs are compared with typical conference travel costs to show the viability of the proposed terminal.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Intelcom ''77 Symposium; Oct 09, 1977 - Oct 15, 1977; Atlanta, GA
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 129
    facet.materialart.
    Unbekannt
    Multiple-access channels without synchronization (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: This paper discusses models for multiple-access communications which take into account the fact that the channel users may not be able to synchronize their transmissions. It is shown that for a broad class of such channels, the capacity region is the same as it would be with user synchronization. Some open problems are discussed.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: International Conference on Communications; Jun 12, 1977 - Jun 15, 1977; Chicago, IL
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 130
    facet.materialart.
    Unbekannt
    Carrier synchronization techniques for unbalanced QPSK signals. I (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: This paper uses MAP estimation techniques to obtain carrier reconstruction circuits for unbalanced QPSK signals. In addition, the performance analysis of these circuits is carried out to the extent that a loop design can proceed. Numerical results are presented in order to demonstrate the utility of the theory developed. This signal design will be used in the development of the Tracking and Data Relay Satellite System (TDRSS) and the Navigation Satellite Timing and Ranging Global Positioning System (NAVSTAR GPS).
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: International Conference on Communications; Jun 12, 1977 - Jun 15, 1977; Chicago, IL
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 131
    facet.materialart.
    Unbekannt
    Spectrally efficient modulation (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: Spectrally efficient modulation, involving the maximization of the transmitted data rate through a specified bandwidth, may aid in alleviating the problem of spectral congestion in the electromagnetic spectrum. Attention is given to pulse-shaping and nonbinary modulation, and particularly to combined amplitude- and phase-modulation. Theoretical performance limits, such as Shannon's bound, are used to assess the effectiveness of the systems described. Consideration is also allotted to spectrally efficient modulation for terrestrial microwave systems, required to provide 1000 voice channels in the 4- and 6-GHz band.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: International Conference on Communications; Jun 12, 1977 - Jun 15, 1977; Chicago, IL
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 132
    facet.materialart.
    Unbekannt
    System design for the digitally implemented communications experiment /DICE/ (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: Full-duplex digital television providing a teleconference capability is to be evaluated in an experimental program utilizing the Communications Technology Satellite. The digitally implemented communications experiment employs a QPSK modulator-demodulator capable of operation over a wide range of bit rates. In addition to simultaneous data transmission (used for digital high-speed facsimiles and remote computer terminals), voice transmission through four-to-one compression will be studied.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: International Conference on Communications; Jun 12, 1977 - Jun 15, 1977; Chicago, IL
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 133
    facet.materialart.
    Unbekannt
    Interaction of electromagnetic and acoustic waves in a stochastic atmosphere (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: This paper considers the interaction of electromagnetic and acoustic waves where a Radio Acoustic Sounding System (RASS) is operated in a stochastic environment characterized by turbulence, winds and mean-temperature gradients. It has been shown that for a RASS operating at acoustic frequencies below a few kilohertz propagating under typical atmospheric conditions, turbulence has little effect on the strength of the received radio signal scattered from the pulse at heights up to a few kilometers. This result implies that the received RF signal level (power) is primarily a function of sound intensity which decreases as x exp minus 2 where x is the altitude.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Union Radio Scientifique Internationale Open Symposium; Apr 28, 1977 - May 06, 1977; Loire-Atlantique; France
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 134
    facet.materialart.
    Unbekannt
    Rain depolarization and attenuation measurements at 11.7, 19.04, and 28.56 GHz - A description of the experiment and some preliminary results (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The considered investigation made use of the Communications Technology Satellite (CTS) downlink and the beacons carried by the Comstar satellites. The general behavior of rain attenuation and depolarization is illustrated with the aid of data from a storm which took place on July 15, 1976. The effect of the rain on the copolarized signal is indicated in a graph. Another graph shows the behavior of the cross-polarized signal component. Phase effects are also considered together with statistical curves for attenuation. The considered data from CTS indicate that, at least during summer convective storms, attenuation at 11.7 GHz is much more severe than anticipated. Attenuation may be a more serious impediment to dual polarized satellite links at this frequency than is depolarization.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Union Radio Scientifique Internationale Open Symposium; Apr 28, 1977 - May 06, 1977; Loire-Atlantique; France
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 135
    facet.materialart.
    Unbekannt
    CTS /Hermes/ - United States experiments and operations summary (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The U.S. experiments conducted with the Communications Technology Satellite, a joint Canadian-U.S. venture launched in 1976, are discussed. The 14/12 GHz frequencies employed by the 200-W transmitter on board the satellite provide two-way television and voice communications. Applications of the satellite in the categories of health care, community services and education are considered; experiments have also made use of the special properties of the super-high frequency band (e.g. link characterization and digital communications). Time-sharing of the 14/12 GHz communication between the U.S. and Canada has functioned well.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Symposium on Hermes (Communications Technology Satellite): Its Performance and Applications; Nov 29, 1977 - Dec 01, 1977; Ottawa; Canada
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 136
    facet.materialart.
    Unbekannt
    A digitally implemented communications experiment utilizing the Hermes /CTS/ satellite (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: Attention is given to an investigation being conducted by NASA-Lewis and Comsat Laboratories which uses the Hermes (CTS) satellite to explain digital link implementation and the advantages it provides over conventional analog systems. The experiment concentrates on developing several video, audio, and data digital communications techniques.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Symposium on Hermes (Communications Technology Satellite): Its Performance and Applications; Nov 29, 1977 - Dec 01, 1977; Ottawa; Canada
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 137
    facet.materialart.
    Unbekannt
    Utilization of NASA Lewis mobile terminals for the Hermes satellite (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The paper describes the portable earth terminal (PET) and the transportable earth terminal (TET) which enable two-way television and voice communication. Both terminals were developed by NASA and utilize the high power of the Hermes satellite. PET is a bus-type vehicle which has receiving equipment for full duplex color television and which can transmit programs originating in either the on-board PET studio or in nearby buildings. PET has a collapsible 2.4-m diameter parabolic antenna interfacing with a 500-watt 14-GHz wideband TV transmitter and a 12-GHz wideband TV receiver system. TET uses two parabolic reflector antennas, 3 m and 1.2 m in diameter, mounted on a flat trailer towed by a truck. TET can receive and relay color TV signals, and its narrowband transmitter can serve as a return audio link permitting a question-and-answer format. Also described are uplink and downlink performance characteristics, operation procedures, and field demonstrations which enabled personnel at several hospitals to participate in a distant medical conference.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Symposium on Hermes (Communications Technology Satellite): Its Performance and Applications; Nov 29, 1977 - Dec 01, 1977; Ottawa; Canada
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 138
    facet.materialart.
    Unbekannt
    A compendium of millimeter wave propagation studies performed by NASA (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: Key millimeter wave propagation experiments and analytical results were summarized. The experiments were performed with the Ats-5, Ats-6 and Comstar satellites, radars, radiometers and rain gage networks. Analytic models were developed for extrapolation of experimental results to frequencies, locations, and communications systems.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-156781
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 139
    facet.materialart.
    Unbekannt
    CTS attenuation and cross-polarization measurements at 11.7 GHz (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The results of data obtained 80 days preceding the solar eclipse shutdown of the CTS 11.7 GHz righthand circularly polarized beacon transmitter are presented. Attenuation and cross polarization isolation were measured. It was determined that depolarization presents a serious limitation to satellite system reliability when frequency reuse by polarization diversity is employed. A 27 db isolation margin would reduce reliability below 99.95%. For the same percentage the required fade margin was below 3 db.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-156771
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 140
    facet.materialart.
    Unbekannt
    Design and demonstration of an advanced data collection/position location system (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The final report on a breadboard evaluation and demonstration program is reported concerning the applicability of MSK modulation and chirp-z transformer technology in Advanced Data Collection/Position Location (ADC/PL) systems. The program effort consisted of three phases - design, testing, and evaluation. Section 2 describes the breadboard hardware built during the design phase of the program, Section 3 describes the tests conducted on the breadboard and the results of the tests, and Section 4 presents a brief analysis and summary of the findings of the breadboard tests and develops a sample ADC/PL system which incorporates both MSK modulation and a chirp-z transformer.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-156748
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 141
    facet.materialart.
    Unbekannt
    Analysis of synthetic aperture radar imagery (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: Some problems faced in applications of radar measurements in hydrology are: (1) adequate calibration of the radar systems and direct digital data will be required in order that repeatable data can be acquired for hydrologic applications; (2) quantitative hydrologic research on a large scale will be prohibitive with aircraft mounted synthetic aperture radar systems due to the system geometry; (3) spacecraft platforms appear to be the best platforms for radar systems when conducting research over watersheds larger than a few square kilometers; (4) experimental radar systems should be designed to avoid use of radomes; and (5) cross polarized X and L band data seem to discriminate between good and poor hydrologic cover better than like polarized data.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-156743 , RSC-3359-2
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 142
    facet.materialart.
    Unbekannt
    Electromagnetic plasma wave emissions from the auroral field lines (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The most important types of auroral radio emissions are reviewed, both from a historical perspective as well as considering the latest results. Particular emphasis is placed on four types of electromagnetic emissions which are directly associated with the plasma on the auroral field lines. These emissions are (1) auroral hiss, (2) saucers, (3) ELF noise bands, and (4) auroral kilometric radiation. Ray tracing and radio direction finding measurements indicate that both the auroral hiss and auroral kilometric radiation are generated along the auroral field lines relatively close to the earth, at radial distances from about 2.5 to 5 R sub e. For the auroral hiss the favored mechanism appears to be amplified Cerenkov radiation. For the auroral kilometric radiation several mechanisms have been proposed, usually involving the intermediate generation of electrostatic waves by the precipitating electrons.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-155172 , U-OF-IOWA-77-36 , Gen. Sci. Assembly of the Intern. Assoc. of Geomagnetism and Aeronomy; Jan 01, 1977; Seattle
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 143
    facet.materialart.
    Unbekannt
    Communication system analysis for manned space flight (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: One- and two-dimensional adaptive delta modulator (ADM) algorithms are discussed and compared. Results are shown for bit rates of two bits/pixel, one bit/pixel and 0.5 bits/pixel. Pictures showing the difference between the encoded-decoded pictures and the original pictures are presented. The effect of channel errors on the reconstructed picture is illustrated. A two-dimensional ADM using interframe encoding is also presented. This system operates at the rate of two bits/pixel and produces excellent quality pictures when there is little motion. The effect of large amounts of motion on the reconstructed picture is described.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-151508
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 144
    facet.materialart.
    Unbekannt
    Solid state Ku-band spacecraft transmitters (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: A transmitter is considered that consists of GaAs IMPATT and Read diodes operating in a microstrip circuit environment to provide amplification with a minimum of 63 db small signal gain and a minimum compressed gain at 5 W output of 57 db. Reported are Schottky-Read diode design and fabrication, microstrip and circulator optimization, preamplifier development, power amplifier development, dc-to-dc converter design, and integration of the breadboard transmitter modules. A four-stage power amplifier in cascade with a three-stage preamplifier had an overall gain of 56.5 db at 13.5 GHz with a power output of 4.5 W. A single-stage Read amplifier delivered 5.9 W with 4 db gain at 22% efficiency.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-152590 , TI-08-77-11
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 145
    facet.materialart.
    Unbekannt
    Final report on technical work accomplished under contract NASw-2953 (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: A report is given on the technical work accomplished in the area of plasma physics. The subjects covered are: (1) oblique whistler instabilities, (2) current-limited electron beam injection, (3) three-dimensional ion sound turbulence, (4) theoretical aspects of sounder antenna operation and (5) whistler modes in bow shock structures.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-153294 , TRW-29697-6002-RU-00
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 146
    facet.materialart.
    Unbekannt
    Research in millimeter wave techniques (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The following is investigated; (1) the design of a 183 GHz single ended fundamental mixer to serve as a back up mixer to the subharmonic mixer for airborne applications, (2) attainment of 6 db single sideband conversion loss with the 6 GHz subharmonic mixer model, together with initial tests to determine the feasibility of pumping the mixer at w sub s/4, (3) additional ground based radiometric measurements, and (4) derivation of equations for power transmission of wire grid interferometers, and initial tests to verify these equations.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-156762 , SATR-6
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 147
    facet.materialart.
    Unbekannt
    A depolarization and attenuation experiment using the CTS satellite (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: Rain attenuation and depolarization data collected on the communications technology satellite 11.7 GHz downlink, and changes made in equipment following rain leak damage to the parametric amplifier are discussed. A 15 GHz radar system is described.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-152535 , QTPR-1
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 148
    facet.materialart.
    Unbekannt
    Aircraft measurement of radio frequency noise at 121.5 MHz, 243 MHz and 406 MHz (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: An airborne survey measurement of terrestrial radio-frequency noise over U.S. metropolitan areas was carried out at 121.5, 243 and 406 MHz with horizontal-polarization monopole antennas. Flights were at 25,000 feet altitude. Radio-noise measurements, expressed in equivalent antenna-noise temperature, indicate a steady-background noise temperature of 572,000 K, at 121.5 MHz, during daylight over New York City. This data is helpful in compiling radio-noise temperature maps; in turn useful for designing satellite-aided, emergency-distress search and rescue communication systems.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-TM-X-71283 , X-952-77-11 , Symp. and Technical Exhibition on Electromagnetic Compatibility; Jun 28, 1977 - Jun 30, 1977; Montreux; Switzerland
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 149
    facet.materialart.
    Unbekannt
    A depolarization and attenuation experiment using the CTS satellite. Volume 2: Data (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: An experiment for measuring precipitation attenuation and depolarization on the CTS 11.7 GHz downlink is described.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-152482
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 150
    facet.materialart.
    Unbekannt
    Repeater in the sky (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The Public Service Communications Satellite (PSCS) program is intended to develop and demonstrate a space system aimed at stimulating future commercial markets in fixed and mobile applications. The services are envisioned for rural areas, regions beyond access to terrestrial systems, or for continuous cross-country applications. The system incorporates a UHF repeater for mobile voice and data experiments; 8 MHz of spectrum is specified for serving 70 channels. This paper describes the PSCS program and discusses some demonstration experiments. A future concept based on large structure multibeam antennas is also discussed.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: National Electronics Conference; Oct 10, 1977 - Oct 12, 1977; Chicago, IL
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 151
    facet.materialart.
    Unbekannt
    Carrier synchronization techniques for unbalanced QPSK signals. II (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: This paper develops a theory for assessing the tracking performance and designing carrier synchronization loops which are to be matched to an unbalanced QPSK signal design. It is assumed that the power split and the I and Q channel data rates are arbitrary. Bit synchronization is assumed to be unavailable for both carrier reconstruction techniques which have been suggested via MAP estimation theory. Numerical results are presented.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: In: NTC ''77; National Telecommunications Conference; Dec 05, 1977 - Dec 07, 1977; Los Angeles, CA
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 152
    facet.materialart.
    Unbekannt
    Bit timing with pulse distortion and intersymbol interference (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: Pulse distortion and intersymbol interference due to insufficient filtering in PCM and PSK channels cause performance degradation in terms of both bit error probabilities and timing errors. This paper reports the results of a study analyzing these effects on bit timing subsystems. Consideration is given to both the filter-rectifier and transition tracking type of timing subsystem. Although both these systems perform similarly in high SNR and ideal pulse models, pulse distortion and intersymbol affects each differently. The primary effects in both systems is to cause the presence of an irreducible mean squared timing error due to the intersymbol which limits the ultimate performance. Design procedures to minimize the anomalies of both systems are presented, and indicate modifications of the standard timing subsystems. It is found that specific design directions depend on whether the intersymbol or the receiver noise tends to dominate.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: In: NTC ''77; National Telecommunications Conference; Dec 05, 1977 - Dec 07, 1977; Los Angeles, CA
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 153
    facet.materialart.
    Unbekannt
    Non-parametric PCM to ADM conversion (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: An all-digital technique to convert pulse code modulated (PCM) signals into adaptive delta modulation (ADM) format is presented. The converter developed is shown to be independent of the statistical parameters of the encoded signal and can be constructed with only standard digital hardware. The structure of the converter is simple enough to be fabricated on a large scale integrated circuit where the advantages of reliability and cost can be optimized. A concise evaluation of this PCM to ADM translation technique is presented and several converters are simulated on a digital computer. A family of performance curves is given which displays the signal-to-noise ratio for sinusoidal test signals subjected to the conversion process, as a function of input signal power for several ratios of ADM rate to Nyquist rate.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: In: NTC ''77; National Telecommunications Conference; Dec 05, 1977 - Dec 07, 1977; Los Angeles, CA
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 154
    facet.materialart.
    Unbekannt
    Minimax decoding of cyclic block codes (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: A minimax decoding algorithm utilizing soft bit detection of an (n,k) cyclic block code is described which will permit the correction of up to n-k bit errors interspersed at random locations throughout the block. The decoding solution consists of: (1) identifying the ordered soft bit set and, (2) finding the minimum order solution to the resulting syndrome equations where the nonzero error vector components are constrained to be a subset of the soft bit set. An efficient implementation of the decoding operation is described. In essence, this algorithm focuses the correction capability of the code on those bit positions which have the lowest a posteriori probabilities of correct detection.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: In: NTC ''77; National Telecommunications Conference; Dec 05, 1977 - Dec 07, 1977; Los Angeles, CA
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 155
    facet.materialart.
    Unbekannt
    On signal design by the R/0/ criterion for non-white Gaussian noise channels (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The use of the cut-off rate criterion for modulation system design is investigated for channels with non-white Gaussian noise. A signal space representation of the waveform channel is developed, and the cut-off rate for vector channels with additive non-white Gaussian noise and unquantized demodulation is derived. When the signal input to the channel is a continuous random vector, maximization of the cut-off rate with constrained average signal energy leads to a water-filling interpretation of optimal energy distribution in signal space. The necessary condition for a finite signal set to maximize the cut-off rate with constrained energy and an equally likely probability assignment of signal vectors is presented, and an algorithm is outlined for numerically computing the optimum signal set. As an example, the rectangular signal set which has the water-filling average energy distribution and the optimum rectangular set are compared.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: In: NTC ''77; National Telecommunications Conference; Dec 05, 1977 - Dec 07, 1977; Los Angeles, CA
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 156
    facet.materialart.
    Unbekannt
    Comparison of convolutional and block code performance on the Rician channel (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The paper is concerned with the relative performance of short constraint length convolutional codes vis-a-vis block codes when used in conjunction with either BPSK or DPSK modulation on the classical Rician fading channel. A variety of soft-decision decoding algorithms is considered for block codes while the Viterbi algorithm is used exclusively for decoding convolutional codes. Results indicate a substantial performance/complexity advantage in favor of short constraint length convolutional codes and Viterbi decoding which increases with fading severity. The work reported here extends the well-known performance advantage of convolutional codes on the AWGN channel to representative fading channels.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: In: NTC ''77; National Telecommunications Conference; Dec 05, 1977 - Dec 07, 1977; Los Angeles, CA
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 157
    facet.materialart.
    Unbekannt
    Measured results of polarization crosstalk cancellation using LMS control (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: This paper discusses the use of wideband decoupling networks for the cancellation of polarization crosstalk in dual-polarized communication links. Measured cancellation performance for an all-electronic IF network and an RF electro-mechanical waveguide network are presented. Each of these networks utilizes LMS-type adaptive control techniques to adjust the cancellation network.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: In: NTC ''77; National Telecommunications Conference; Dec 05, 1977 - Dec 07, 1977; Los Angeles, CA
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 158
    facet.materialart.
    Unbekannt
    Antenna bias rigging for performance objective (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: An optimum bias rigging for a paraboloidal antenna can be used to minimize the expected average mean-square half-pathlength surface deviations. Statistics of deep space planetary missions are employed to develop weighting factors for antenna elevation angles during these missions. A procedure is shown to compute the optimum rigging angle from these weights.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Mechanical Engineering in Radar Symposium; Nov 08, 1977 - Nov 10, 1977; Arlington, VA
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 159
    facet.materialart.
    Unbekannt
    Evaluating computed distortions of parabolic reflectors (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: Distortion outputs from structural analysis of a 64-m paraboloidal reflector are analyzed by two computer programs for their radio-frequency performance characteristics. The computed and field measured values are compared.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Mechanical Engineering in Radar Symposium; Nov 08, 1977 - Nov 10, 1977; Arlington, VA
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 160
    facet.materialart.
    Unbekannt
    Approximations to microwave attenuation in precipitation (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: A three-term approximation and a discrete drop-size distribution have been used to obtain an analytical expression for the microwave attenuation coefficient for precipitation. Results compared to an exact calculation using the same drop size distribution showed a relative difference of 50% or less over a broad range of rainrates (5-150 mm/hr) and wavelengths (2-5 cm). Since the use of a discrete drop-size distribution is computationally complex, the exponential size distribution formulated by Marshall and Palmer (1948) was studied. This distribution resulted in an overprediction of the attenuation coefficient of as much as 100% at a 2 cm wavelength and a 150 mm/hr rainrate, although the prediction was much closer at lower rainrates and different wavelengths.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Conference on Radar Meteorology; Oct 26, 1976 - Oct 29, 1976; Seattle, WA
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 161
    facet.materialart.
    Unbekannt
    K-band attenuation by rain at constant reflectivity (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The paper considers a radar method of determining rain intensity which uses a dual wavelength system to measure both reflectivity Z and attenuation A and solving for the constants in an assumed exponential drop size distribution. Calculations are confined to the K-band, relations between A and the rain intensity R being determined for different values of Z for wavelengths of 0.86 and 1.24 cm. It is shown that measurements of reflectivity and attenuation by a dual wavelength radar can provide separate derivations of rain intensity. Available data on errors in an A-R relation indicate that the derivation from the attenuation measurement will be no better than from the Z-R relation.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Conference on Radar Meteorology; Oct 26, 1976 - Oct 29, 1976; Seattle, WA
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 162
    facet.materialart.
    Unbekannt
    A digitally implemented communications experiment utilizing the Hermes (CTS) satellite (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The Hermes (CTS) experiment program made possible a significant effort directed toward new developments which will reduce the costs associated with the distribution of satellite services. Advanced satellite transponder technology and small inexpensive earth terminals were demonstrated as part of the Hermes program. Another system element that holds promise for reduced transmission cost is associated with the communication link implementation. An experiment is described which uses CTS to demonstrate digital link implementation and its advantages over conventional analog systems. A Digitally Implemented Communications experiment which demonstrates the flexibility and efficiency of digital transmission of television video and audio, telephone voice and high-bit-rate data is also described. Presentation of the experiment concept which concentrates on the evaluation of full-duplex digital television in the teleconferencing environment is followed by a description of unique equipment that was developed.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-TM-73827 , Symp. on Hermes (Comm. Technol. Satellite) its Performance and Appl.; Nov 29, 1977 - Dec 01, 1977; Ottawa, Ontario; Canada
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 163
    facet.materialart.
    Unbekannt
    New lidar concept for measuring the slant range transmission in aircraft landing approaches (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The single-scatter, single-wavelength, scalar-backscatter lidar equation is investigated to determine the transmission along a line from a point on the ground to what is known as the decision point on the 3 degree aircraft glide slope. It may be applied in aircraft landing approaches for measuring the slant range transmission.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: International Laser Radar Conference on Laser Atmospheric Studies; Jun 06, 1977 - Jun 09, 1977; Philadelphia, PA; US
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 164
    facet.materialart.
    Unbekannt
    A Technique for Measuring Rotocraft Dynamic Stability in the 40 by 80 Foot Wind Tunnel (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: An on-line technique is described for the measurement of tilt rotor aircraft dynamic stability in the Ames 40- by 80-Foot Wind Tunnel. The technique is based on advanced system identification methodology and uses the instrumental variables approach. It is particulary applicable to real time estimation problems with limited amounts of noise-contaminated data. Several simulations are used to evaluate the algorithm. Estimated natural frequencies and damping ratios are compared with simulation values. The algorithm is also applied to wind tunnel data in an off-line mode. The results are used to develop preliminary guidelines for effective use of the algorithm.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-151955
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 165
    facet.materialart.
    Unbekannt
    Meteorological radar facility (MRF) slot conductance investigations (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: A preliminary meteorological radar facility (MRF) array design was completed in support of the slot conductance measurement program. Three different slot measurement techniques were evaluated. The selection of the probe comparison measurement technique was selected as the principal experimental method with the impedance measurement technique chosen to measure a few higher conductance slots to be used as reference slots. The impedance of 43 slots in 0.9 x 0.4 inch standard waveguide and of 40 slots in 0.835 x 0.4 inch waveguide was measured. Also, impedance measurements were made of a few slots using image planes to simulate mutual coupling effects. The measured and theoretical conductance, susceptance, and radiation phase data are presented in graphic form as a function of slot displacement for constant slot length, and of slot length for constant slot displacement. It is concluded that the proposed MRF array design approach is a feasible one.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-152465 , P77-20 , HAC-REF-D7036
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 166
    facet.materialart.
    Unbekannt
    Federal research and development for satellite communications (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A Committee on Satellite Communication (COSC) was formed under the auspices of the Space Applications Board (SAB) in order to study Federal research and development on satellite communications (SC). Discussion on whether to continue the research and development and the proper role of the Federal Government are addressed. Discussion focussed on six possible options for a Federal role in SC research and development: (1) the current NASA SC program; (2) an expanded NASA SC technology program; (3) a SC technology flight test support program; (4) an experimental SC technology flight program; (5) an experimental public service SC system program; and (6) an operational public service SC system program. Decision criteria and recommendations are presented.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-157392
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 167
    facet.materialart.
    Unbekannt
    Adaptive delta modulation systems for video encoding (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: This paper describes several adaptive delta modulators designed to encode video signals. One- and two-dimensional ADM algorithms are discussed and compared. Results are shown for bit rates of 2 bits/pixel, 1 bit/pixel and 0.5 bits/pixel. Pictures showing the difference between the encoded-decoded pictures and the original pictures are presented. Results are also presented to illustrate the effect of channel errors on the reconstructed picture. A two-dimensional ADM using interframe encoding is also presented. This system operates at the rate of 2 bits/pixel and produces excellent quality pictures when there is little motion. We also describe and illustrate the effect of large amounts of motion on the reconstructed picture.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Communications; COM-25; Nov. 197
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 168
    facet.materialart.
    Unbekannt
    A model for microwave intensity propagation in an inhomogeneous medium (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A combined analytic and phenomenological approach, utilizing Maxwell's equations in the Born approximation with radiative transfer theory, is used to describe the propagation of microwave intensity in a scattering medium characterized by three-dimensional random fluctuations in refractive index, as well as nonrandom variations in permittivity, temperature, and loss. This approach yields microwave intensities as a function of polarization, direction, and position. Numerical techniques are presented to solve the transport equations, which include cases of spatially varying coefficients, and highly peaked phase functions. Some computed results illustrating the behavior of microwave intensity in various media are presented. Included are the angular and frequency spectra of thermal emission from semi-infinite media, and the diffuse transmission and reflection response of a scattering layer. The effects of scatterer geometry and scale sizes; correlation function; and gradients in temperature, loss, and scattering parameters are also demonstrated. This model should be particularly useful in interpreting active and passive remote sensing data.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Antennas and Propagation; AP-25; Nov. 197
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 169
    facet.materialart.
    Unbekannt
    Prediction of slant path rain attenuation statistics at various locations (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The paper describes a method for predicting slant path attenuation statistics at arbitrary locations for variable frequencies and path elevation angles. The method involves the use of median reflectivity factor-height profiles measured with radar as well as the use of long-term point rain rate data and assumed or measured drop size distributions. The attenuation coefficient due to cloud liquid water in the presence of rain is also considered. Absolute probability fade distributions are compared for eight cases: Maryland (15 GHz), Texas (30 GHz), Slough, England (19 and 37 GHz), Fayetteville, North Carolina (13 and 18 GHz), and Cambridge, Massachusetts (13 and 18 GHz).
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Radio Science; 12; Sept
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 170
    facet.materialart.
    Unbekannt
    Performance of DPSK with convolutional encoding on time-varying fading channels (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The bit error probability performance of a differentially-coherent phase-shift keyed (DPSK) modem with convolutional encoding and Viterbi decoding on time-varying fading channels is examined. Both the Rician and the lognormal channels are considered. Bit error probability upper bounds on fully-interleaved (zero-memory) fading channels are derived and substantiated by computer simulation. It is shown that the resulting coded system performance is a relatively insensitive function of the choice of channel model provided that the channel parameters are related according to the correspondence developed as part of this paper. Finally, a comparison of DPSK with a number of other modulation strategies is provided.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Communications; COM-25; Oct. 197
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 171
    facet.materialart.
    Unbekannt
    Amplitude scintillations on earth-space propagation paths at 2 and 30 GHz (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Amplitude scintillation measurements were made simultaneously at 2.075 and 30 GHz on earth-space propagation paths over elevation angles in the range 0.4 to 44 deg. The experiment was performed as the Applications Technology Satellite (ATS-6) was moved slowly from a synchronous position over Africa to a new synchronous position over the United States. The received signal, variance, level, covariance, spectra and fade distributions are discussed as functions of the path elevation angle. These results are also compared wherever possible with similar measurements made earlier at 20 and 30 GHz.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-156785 , ESL-4299-4
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 172
    facet.materialart.
    Unbekannt
    An analysis of multi-frequency high resolution radar rain rate data (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Approximately 100,000 records of data at 3.05, 9.35, and 15.56 GHz, each set associated with a single look angle, are edited and analyzed to determine the characteristic dimensions of the rain cells observed and the rain rate distributions within these cells. The results, consistent with earlier results, demonstrate the feasibility of using attenuating frequency radars for high resolution rain rate measurements.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-156734 , ESL-784650-3
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 173
    facet.materialart.
    Unbekannt
    Mobile multiple access study (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Multiple access techniques (FDMA, CDMA, TDMA) for the mobile user and attempts to identify the current best technique are discussed. Traffic loading is considered as well as voice and data modulation and spacecraft and system design. Emphasis is placed on developing mobile terminal cost estimates for the selected design. In addition, design examples are presented for the alternative techniques of multiple access in order to compare with the selected technique.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-156650
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 174
    facet.materialart.
    Unbekannt
    Optimization of MLS receivers for multipath environments (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Optimal design studies of MLS angle-receivers and a theoretical design-study of MLS DME-receivers are reported. The angle-receiver results include an integration of the scan data processor and tracking filter components of the optimal receiver into a unified structure. An extensive simulation study comparing the performance of the optimal and threshold receivers in a wide variety of representative dynamical interference environments was made. The optimal receiver was generally superior. A simulation of the performance of the threshold and delay-and-compare receivers in various signal environments was performed. An analysis of combined errors due to lateral reflections from vertical structures with small differential path delays, specular ground reflections with neglible differential path delays, and thermal noise in the receivers is provided.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-155230 , UVA/528062/EE77/104
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 175
    facet.materialart.
    Unbekannt
    Disaster warning system study summary (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A conceptual satellite system to replace or complement NOAA's data collection, internal communications, and public information dissemination systems for the mid-1980's was defined. Program cost and cost sensitivity to variations in communications functions are analyzed.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-TM-73797 , E-9366
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 176
    facet.materialart.
    Unbekannt
    Developing satellite communications for public service: Prospects in four service areas (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The Public Service Satellite Consortium evaluated prospects for satellite telecommunications in four areas of the public service: the U.S. health care system, elementary and secondary education, American libraries, and that sector of the public service which is concerned with the provision of continuing education to health professionals. Three important conclusions were reached. First, throughout the public service there are three recurring needs: improved access, cost containment, and maintenance of quality. Appropriate application of communication satellite systems could ameliorate each of these concerns. Second, there appears to be an enormous latent demand for data communication services throughout the public service. The potential demand in 1982 to support requirements in hospital administration, library services and other information-retrieval activities, equipment maintenance, and environmental monitoring may be in excess of $300 million a year. Third, administrative applications of data communication networks show particular promise, especially in rural areas.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-156637
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 177
    facet.materialart.
    Unbekannt
    Retransmission error control with memory (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: In this paper, an error control technique that is a basic improvement over automatic-repeat-request ARQ is presented. Erroneously received blocks in an ARQ system are used for error control. The technique is termed ARQ-with-memory (MRQ). The general MRQ system is described, and simple upper and lower bounds are derived on the throughput achievable by MRQ. The performance of MRQ with respect to throughput, message delay and probability of error is compared to that of ARQ by simulating both systems using error data from a VHF satellite channel being operated in the ALOHA packet broadcasting mode.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Communications; COM-25; May 1977
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 178
    facet.materialart.
    Unbekannt
    Effects of random phase changes on the formation of synthetic aperture radar imagery (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The effects of Gaussian random fluctuation and linear change of the echo phase on the response of the azimuth matched processor of a synthetic aperture radar (airborne or spaceborne for ocean-surface sensing) is analyzed numerically. It is found that the random fluctuation would not alter appreciably the processor response if its standard deviation is less than pi, while its normalized correlation time is larger than 1. If these two bounding conditions are not satisfied, then the sidelobe level becomes relatively large and overshadows the central peak. In the case of linear displacement it is found that the main effect is the spatial displacement of the point scatterer in the image plane.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Antennas and Propagation; AP-25; Jan
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 179
    facet.materialart.
    Unbekannt
    An approximate method for design and analysis of an ALOHA system (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: An approximate method for the design and performance prediction of a multiaccess communication system which employs the ALOHA packet-switching technique is developed, based on the use of a diffusion process approximation of an ALOHA-like system (with or without time-slotting). A simple closed-form solution for the variable Q(t), a variant of the number of backlog messages at time t, is given in terms of a few system and user parameters. Final results are expressed in terms of ordinary performance measures such as throughput and average delay. Several numerical examples are given to demonstrate the usefulness of the approximation technique developed.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Communications; COM-25; Jan. 197
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 180
    facet.materialart.
    Unbekannt
    A bound and approximation of delay distribution for fixed-length packets in an unslotted ALOHA channel and a comparison with time division multiplexing /TDM/ (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Communications; COM-25; Jan. 197
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 181
    facet.materialart.
    Unbekannt
    Optimal design of mixed-media packet-switching networks - Routing and capacity assignment (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: This paper considers a mixed-media packet-switched computer communication network which consists of a low-delay terrestrial store-and-forward subnet combined with a low-cost high-bandwidth satellite subnet. We show how to route traffic via ground and/or satellite links by means of static, deterministic procedures and assign capacities to channels subject to a given linear cost such that the network average delay is minimized. Two operational schemes for this network model are investigated: one is a scheme in which the satellite channel is used as a slotted ALOHA channel; the other is a new multiaccess scheme we propose in which whenever a channel collision occurs, retransmission of the involved packets will route through ground links to their destinations. The performance of both schemes is evaluated and compared in terms of cost and average packet delay tradeoffs for some examples. The results offer guidelines for the design and optimal utilization of mixed-media networks.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Communications; COM-25; Jan. 197
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 182
    facet.materialart.
    Unbekannt
    The throughput of packet broadcasting channels (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A unified presentation of packet broadcasting theory is presented. Section II introduces the theory of packet broadcasting data networks. Section III provides some theoretical results on the performance of a packet broadcasting network when users have a variety of data rates. Section IV deals with packet broadcasting networks distributed in space, and in Section V some properties of power-limited packet broadcasting channels are derived, showing that the throughput of such channels can approach that of equivalent point-to-point channels.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: IEEE Transactions on Communications; COM-25; Jan. 197
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 183
    facet.materialart.
    Unbekannt
    Mariner Venus Mercury 1973 S/X-band experiment (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The S/X-band experiment on the Mariner Venus/Mercury 1973 spacecraft constituted a unique opportunity to demonstrate the capability of an X-band downlink coherent with the normal S-band downlink. This was both a technological and scientific experiment, and the results indicated that it was successful in both cases. Analysis of the tracking data shows that the new S/X data type was capable of reducing the miss distance at the planet Mercury by 80% (post-processed data). The use of S/X electron content was demonstrated by comparison with Faraday rotation data. An X-band turnaround telemetry experiment showed the feasibility of a planetary X-band link. In the science area, the model atmospheric environment of Venus was refined. The ionosphere of the planet was measured to a higher accuracy than before, and the value of the dual-frequency link for measuring the scale size of turbulence was demonstrated. The estimate of the scale size was increased from 100 m to above 5 km.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-154105 , JPL-PUBL-77-17
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 184
    facet.materialart.
    Unbekannt
    Wideband heterodyne receiver for laser communication system (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A heterodyne receiver for laser communication is described which includes a front end having a cooled photomixer contained in a hermetically sealed spaced quality housing designed for wide bandwidth transmission. The photomixer is coupled through a wideband preamplifier to the receiver back end which includes a frequency tracking network and demodulating equipment. The receiver is capable of tracking a Doppler frequency shift of 750 MHz, positive or negative, and has an instantaneous intermediate frequency information bandwidth of 400 MHz. The receiver system is also capable of operating over a wide temperature range and is designed to be suitable for use in outer space communication.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 185
    facet.materialart.
    Unbekannt
    Whistler modes in bow shocks (1977)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The behavior of the whistler mode is characterized for arbitrary angles of propagation to B, under representative solar wind conditions.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: Final Report on Tech. Work accomplished under contract NASw-2953; 7 p
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 186
    facet.materialart.
    Unbekannt
    Monte Carlo analysis of uncertainty propagation in a stratospheric model. 2: Uncertainties due to reaction rates (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A concise stratospheric model was used in a Monte-Carlo analysis of the propagation of reaction rate uncertainties through the calculation of an ozone perturbation due to the addition of chlorine. Two thousand Monte-Carlo cases were run with 55 reaction rates being varied. Excellent convergence was obtained in the output distributions because the model is sensitive to the uncertainties in only about 10 reactions. For a 1 ppby chlorine perturbation added to a 1.5 ppby chlorine background, the resultant 1 sigma uncertainty on the ozone perturbation is a factor of 1.69 on the high side and 1.80 on the low side. The corresponding 2 sigma factors are 2.86 and 3.23. Results are also given for the uncertainties, due to reaction rates, in the ambient concentrations of stratospheric species.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-TM-X-71339 , X-624-77-123
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 187
    facet.materialart.
    Unbekannt
    Hardware simulation of KU-band spacecraft receiver and bit synchronizer, phase 2, volume 1 (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The acquisition behavior of the PN subsystem of an automatically acquiring spacecraft receiver was studied. A symbol synchronizer subsystem was constructed and integrated into the composite simulation of the receiver. The overall performance of the receiver when subjected to anomalies such as signal fades was evaluated. Potential problems associated with PN/carrier sweep interactions were investigated.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-151439 , TR-03-75-06-5
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 188
    facet.materialart.
    Unbekannt
    Comparison of finite source and plane wave scattering from corrugated surfaces (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The choice of a plane wave to represent incident radiation in the analysis of scatter from corrugated surfaces was examined. The physical optics solution obtained for the scattered fields due to an incident plane wave was compared with the solution obtained when the incident radiation is produced by a source of finite size and finite distance from the surface. The two solutions are equivalent if the observer is in the far field of the scatterer and the distance from observer to scatterer is large compared to the radius of curvature at the scatter points, condition not easily satisfied with extended scatterers such as rough surfaces. In general, the two solutions have essential differences such as in the location of the scatter points and the dependence of the scattered fields on the surface properties. The implication of these differences to the definition of a meaningful radar cross section was examined.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-TM-X-71329 , X-953-77-111
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 189
    facet.materialart.
    Unbekannt
    Market study: Tactile paging system (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A market survey was conducted regarding the commercialization potential and key market factors relevant to a tactile paging system for deaf-blind people. The purpose of the tactile paging system is to communicate to the deaf-blind people in an institutional environment. The system consists of a main console and individual satellite wrist units. The console emits three signals by telemetry to the wrist com (receiving unit) which will measure approximately 2 x 4 x 3/4 inches and will be fastened to the wrist by a strap. The three vibration signals are fire alarm, time period indication, and a third signal which will alert the wearer of the wrist com to the fact that the pin on the top of the wrist is emitting a morse coded message. The Morse code message can be felt and recognized with the finger.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-153252
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 190
    facet.materialart.
    Unbekannt
    Computer program for analysis of coupled-cavity traveling wave tubes (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A flexible, accurate, large signal computer program was developed for the design of coupled cavity traveling wave tubes. The program is written in FORTRAN IV for an IBM 360/67 time sharing system. The beam is described by a disk model and the slow wave structure by a sequence of cavities, or cells. The computational approach is arranged so that each cavity may have geometrical or electrical parameters different from those of its neighbors. This allows the program user to simulate a tube of almost arbitrary complexity. Input and output couplers, severs, complicated velocity tapers, and other features peculiar to one or a few cavities may be modeled by a correct choice of input data. The beam-wave interaction is handled by an approach in which the radio frequency fields are expanded in solutions to the transverse magnetic wave equation. All significant space harmonics are retained. The program was used to perform a design study of the traveling-wave tube developed for the Communications Technology Satellite. Good agreement was obtained between the predictions of the program and the measured performance of the flight tube.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-TN-D-8492 , E-8839
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 191
    facet.materialart.
    Unbekannt
    The plan for the economic evaluation of the public service communication satellite system (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A plan for the economic evaluation of the Public Service Communications Satellite (PSCS) within domestic markets is presented. It extends through the planning, performance and evaluation of economic experiments following the launch of the PSCS in 1982, and includes the consideration of how the results of these experiments impact the transfer from demonstration to operations. The implementation of this plan will provide information needed to understand and manage the economic and social impacts of the PSCS program.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-153007 , REPT-77-263-4
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 192
    facet.materialart.
    Unbekannt
    Hybrid receiver study (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The results are presented of a 4 month study to design a hybrid analog/digital receiver for outer planet mission probe communication links. The scope of this study includes functional design of the receiver; comparisons between analog and digital processing; hardware tradeoffs for key components including frequency generators, A/D converters, and digital processors; development and simulation of the processing algorithms for acquisition, tracking, and demodulation; and detailed design of the receiver in order to determine its size, weight, power, reliability, and radiation hardness. In addition, an evaluation was made of the receiver's capabilities to perform accurate measurement of signal strength and frequency for radio science missions.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-151984
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 193
    facet.materialart.
    Unbekannt
    Microwave performance characterization of large space antennas (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Performance capabilities of large microwave space antenna configurations with apertures generally from 100 wavelengths upwards are discussed. Types of antennas considered include: phased arrays, lenses, reflectors, and hybrid combinations of phased arrays with reflectors or lenses. The performance characteristics of these broad classes of antennas are examined and compared in terms of applications.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-153206 , JPL-PUBL-77-21
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 194
    facet.materialart.
    Unbekannt
    Unbalanced quadriphase demodulator (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A new and improved apparatus and method are described for demodulation of quaternary phase shift keyed (QPSK) data, particularly unbalanced QPSK. Phase adjustment of the output of a phase locked loop local oscillator is performed to reduce sensitivity to amplitude variations internal to the demodulator.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 195
    facet.materialart.
    Unbekannt
    Transmitter experiment package for the communications technology satellite (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The operating requirements, system design characteristics, high voltage packaging considerations, nonstandard components development, and test results for the transmitter experiment package (TEP) are described. The TEP is used for broadcasting power transmission from the Communications Technology Satellite. The TEP consists of a 12 GHz, 200-watt output stage tube (OST), a high voltage processing system that converts the unregulated spacecraft solar array power to the regulated voltages required for OST operation, and a variable conductance heat pipe system that is used to cool the OST body.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-135035
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 196
    facet.materialart.
    Unbekannt
    Sampling video compression system (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A system for transmitting video signal of compressed bandwidth is described. The transmitting station is provided with circuitry for dividing a picture to be transmitted into a plurality of blocks containing a checkerboard pattern of picture elements. Video signals along corresponding diagonal rows of picture elements in the respective blocks are regularly sampled. A transmitter responsive to the output of the sampling circuitry is included for transmitting the sampled video signals of one frame at a reduced bandwidth over a communication channel. The receiving station is provided with a frame memory for temporarily storing transmitted video signals of one frame at the original high bandwidth frequency.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 197
    facet.materialart.
    Unbekannt
    Patterns of broad-beam antennas of different polarizations next to simple Hangar models (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Broad-beam antennas of different polarizations radiating next to simple hangar models are investigated. Expressions that represent the elevation-plane patterns of slots in and 1/4 wavelength monopoles on a finite rectangular ground plane upon which a rectangular scattering object was placed were derived using geometrical theory of diffraction. These expressions were obtained by superposing the infinite ground plane solutions, reflected field solutions from the scattering object and diffracted field solutions in their respective regions of validity. Patterns for a 1/2 wavelength slot and 1/4 wavelength electric monopole are verified experimentally for a number of source locations. Data pertaining to the polarization question in regard to the multipath problem are presented.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-TM-X-71940
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 198
    facet.materialart.
    Unbekannt
    Communications technology satellite output-tube design and development (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The design and development of a 200-watt-output, traveling-wave tube (TWT) for the Communications Technology Satellite (CTS) is discussed, with emphasis on the design evolution during the manufacturing phase of the development program. Possible further improvements to the tube design are identified.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-TM-X-3480 , E-8776
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 199
    facet.materialart.
    Unbekannt
    Pseudo noise test set operation manual (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Pseudonoise (PN) test set was designed to provide a reliable, operationally simple unit which allows the previously mentioned analog rms end-to-end error measurement of most communication systems to be easily performed. It also provides a band-limited pseudorandom noise as input, thereby escaping the disadvantages of most deterministic signals while retaining the advantages of using true-band-limited noise. In addition, the PN test set has the capability to be used as a means with which the autocorrelation function and impulse response may be determined for certain systems.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-151248
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 200
    facet.materialart.
    Unbekannt
    L-band tone-code-data transponder calibration (1977)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The objectives of this program were to identify and quantify factors which affect the performance of the L-band tone-code-data ranging transponders. Specific objectives included the following: (1) assemble the L-band ranging transponder, previously deployed in Hawaii for the tracking of the ATS-5 satellite, at the GE Radio-Optical Observatory; (2) configure the observatory to conduct calibration exercises with the transponder; and (3) conduct sufficient calibration experiments to demonstrate factors which degrade transponder accuracy, precision, and reliability, to quantify these factors where possible, and to verify long term transponder stability under controlled conditions.
    Schlagwort(e): COMMUNICATIONS AND RADAR
    Materialart: NASA-CR-152471 , SRD-77-038
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...