• A Fast Complex Integer Convolution Using a Hybrid Transform

      Reed, I. S.; Truong, T. K.; University of Southern California; California Institute of Technology (International Foundation for Telemetering, 1978-11)
      In this paper it is shown that the cyclic convolution of complex values can be performed by a hybrid transform. This transform is a combination of a Winograd transform, and a fast complex integer transform developed previously by the authors. This new hybrid algorithm requires fewer multiplications than any previously known algorithm.
    • Fast Fourier Transform Algorithm Formulation

      Thong, Tran; General Electric Company (International Foundation for Telemetering, 1978-11)
      A new unified formulation of the fast Fourier transform based on the unwrapping of a multi-dimensional array is presented. The decimation in time FFT algorithms is treated in detail. The decimation in frequency algorithms is then discussed.
    • FET Amplifiers for Communications Applications

      Kennedy, W. Keith, Jr.; Watkins-Johnson Company (International Foundation for Telemetering, 1978-11)
      The Field Effect Transistor (FET) is revolutionizing microwave communications with both its low noise performance and high dynamic range. This paper emphasizes developed amplifier hardware available today for both ground and satellite applications. The focus is on the noise figures and output powers available from 4 to 15 GHz.
    • Fiber Optic Sensors for Military, Industrial and Commercial Applications

      James, K. A.; Quick, W. H.; Strahan, V. H.; Rockwell International Corporation (International Foundation for Telemetering, 1978-11)
      This paper presents concepts for fiber optic sensors. Such sensors have many inherent advantages over conventional sensors - including digital format and noise immunity. Four examples of specific sensor system designs are discussed - each of which demonstrates a different optical modulation format. The birefringent temperature transducer illustrates direct digital signal modulation. The temperature/pressure dependent semiconductor filter illustrates high-pass optical wavelength signal encoding, while the coupled polarized-mode transducer shows how a solid-state sensor can produce narrow-bandpass optical-wavelength signal encoding. Finally, the luminescent temperature sensor illustrates a manner in which a solid-state sensor can be constructed to produce pulse-width modulation of an optical signal. The potential for fiber-optics sensors adds one more facet to the growing fiber optics market.
    • A Flexible User Oriented Approach to Communications Systems Simulation

      Fashano, M.; Austin, M. C.; Hughes Aircraft Company (International Foundation for Telemetering, 1978-11)
      An advanced software/hardware computer system developed for the simulation of communications systems is described. This user oriented system allows for flexible and efficient modeling and simulation of complex communications systems. Excellent agreement between simulation and measured results has consistently valididated the simulation approach.
    • Future Automated Spacecraft as an End-to-End System Element

      Bird, Thomas H.; NASA - Jet Propulsion Laboratory (International Foundation for Telemetering, 1978-11)
      Concepts for a highly automated spacecraft, which is much more independent of ground operations than current spacecraft, have been investigated. Applicable systems and technology requirements are identified for maximum onboard automation of mission functions. A spacecraft concept which requires infrequent ground contact while increasing mission effectiveness is described. The potential impact of such a system on end-to-end system design is discussed.
    • GDSC Aerospace Test System (ATS)

      Layton, J.; Schiano, C.; Grumman Data Systems Corp. (International Foundation for Telemetering, 1978-11)
      Grumman Data Systems Corporation (GDSC) is presently developing another in a series of computerized realtime systems which accepts, preprocesses, analyzes and displays telemetry and range data. This new Aerospace Test System (ATS) will first be utilized by the Navy at the Pacific Missile Test Center (PMTC). The computerized test system will analyze data, in realtime, being telemetered from missiles, aircrafts and satellities. The system will accept, decommutate/demodulate, preprocess, analyze and display data being transmitted in the forms of PCM, PDM, PAM, and FM. The system will allow test personnel to continually monitor, in realtime, critical raw and calculated parameters. The answers provided to test personnel, in one phase of the mission, will give them the ability to proceed into the next with a high degree of confidence. The vast amounts of data acceptable by the system, together with its analytical and display capabilities will allow test personnel to accomplish several tests during a single time frame. The system will also allow test personnel to be in complete control of their mission via the data uplink capability. It is a system that support Batch, Time Share, and Remote job entry processing concurrently. Utilized properly, it can greatly reduce the quantity and increase the quality of batch processing.
    • Genesis and Design of the Tracking, Telemetry, and Command System for the Navstar Global Positioning System

      Hoff, Charles S.; The Aerospace Corporation (International Foundation for Telemetering, 1978-11)
      The genesis and design of a unique Tracking, Telemetry, and Command (TT&C) System for the Navstar Global Positioning System (GPS) is described from the perspective of the System Architect/Engineer. Working from the diverse and sometimes conflicting mission requirements, derivative performance requirements for the TT&C System were generated. System design tradeoffs were performed in an effort to compromise conflicting requirements which affected the frequency domain, link budgets, antenna sizing, and modulation schemes. The characteristics of the resulting TT&C System included the following: a. Primary uplinking to the satellite on a spread spectrum secure link at X-Band. b. Use of a closed-loop uplink which takes advantage of existing onboard functions as references to achieve precise ground-space synchronization. c. Incorporation of state-of-the-art error control techniques to achieve high net data throughputs with concurrently "zero error" data transfer from ground to space. d. Hybrid frequency ground antennas to accommodate both the primary and backup command links, with compatible telemetry downlinks. A common S-Band frequency input within the satellite to both the primary wideband Pseudo Random Noise (PRN) correlation receiver and the backup Space Ground Link System (SGLS) receiver.
    • A Geometric Moment Bounding Algorithm

      King, Maurice A., Jr.; The Aerospace Corporation (International Foundation for Telemetering, 1978-11)
      There are many important problems in the field of communications theory whose solution is the expectation of a function of a random variable. Examples include linear interference problems such as intersymbol interference and co-channel interference. In these cases, it is often not computationally feasible to evaluate the expectation exactly. This paper presents an algorithm that will compute tight upper and lower bounds to generalized moments of a broad class of random variables. The procedure is based on an isomorphism theorem from Game Theory. The technique is easily understood while yielding excellent results for this class of communication problems.
    • Gigabit Detectors for Visible Space Laser Communications

      Green, Samuel I.; McDonnell Douglas Astronautics Company (International Foundation for Telemetering, 1978-11)
      Performance data taken on several candidate high data rate laser communications photodetectors are presented. Measurements of bit error rate versus signal level were made in a 532 nm system at 500 Mbps.
    • GPS Overview and User Equipment Antijam Design

      Hemesath, Norbert B.; Hutchinson, William M.; Rockwell International (International Foundation for Telemetering, 1978-11)
      The Global Positioning System (GPS) features an all-weather global coverage navigation sensor with 0.01-nmi positioning accuracy. In the following paper, GPS is described with emphasis on antijam considerations developed in the USAF AFAL Generalized Development Model, GDM. Section 1 provides an overview of the GPS ground, space, and user segments. Section 2 describes antijam issues and techniques applicable to GPS. Section 3 describes the GDM design with emphasis on antijam. features. The objectives of the paper are thereby threefold. The first is to give an overview of GPS, how it works, its participants, and its status. The second is to provide a tutorial discussion of spread spectrum receiver design related to GPS (some knowledge of signal processing principles is therein assumed). The third is to provide an example of GPS receiver design which incorporates antijam features.
    • The GPS Satellite and Payload

      Codik, Andrew; Gronlund, Robert A.; Rockwell International Corporation (International Foundation for Telemetering, 1978-11)
      The NAVSTAR/Global Positioning System Satellite is briefly outlined as is the technique for navigation using signals from such satellites. A description of the GPS navigation subsystem with emphasis on its microprocessor and its interfaces and software routines is given.
    • GPS User Equipment, A Concept in Modular Design

      Candy, Donald W.; Hoover, Wayne M.; Texas Instrument Incorporated (International Foundation for Telemetering, 1978-11)
      A brief introduction to the Global Positioning System is presented. Functional modularity of GPS User Equipment systems and subsystems is studied. Physical modularity and commonality of hardware and software functions are discussed with respect to Design To Cost (DTC) and Life Cycle Cost (LCC) goals. Commonality of hardware and software support systems is explored with respect to increased development efficiency. Finally, a composite overview of the Texas Instruments High Dynamics and Manpack Vehicular User Equipments is presented with emphasis placed on the use of technology and vertical integration for DTC/LCC.
    • A Hardware Comparison of Intermicroprocessor Communications Techniques

      Korgel, C.; Lohaus, T.; Pape, D.; Martin Marietta Corporation (International Foundation for Telemetering, 1978-11)
      A generalized multimicroprocessor utilizing the TI9900 and AMD2901 microprocessors is presented. Different types of microprocessors are used to provide extensive computational capability, versatile interprocessor communications, high reliability, and system flexibility. The system is especially suitable for high speed signal processing, data processing, and data handling. Measured data on the speed of interprocessor communication for three techniques is presented along with a comparative assessment of flexibility and reliability for the techniques.
    • High Density 42-Track Magnetic Tape System

      Montgomery, J. H.; Martin Marietta Corporation (International Foundation for Telemetering, 1978-11)
      Design and development of a 42-track high density magnetic tape system for the NASA SEASAT program is described. Both record and playback at a nominal 120 megabits per second from a single data stream was achieved on a 1-inch mylar tape with bit error rate better than 1 x 10⁻⁶ without error correction. Solutions are presented to the requirements of data encoding, high bit rates, recovery from tape dropouts, and efficient use of tracks. This now operational system features a Channel Performance Status Panel, a Tape Bypass Mode, and a MUX/DEMUX unit capable of operating at 150 megabits per second.
    • High Linear Density Recording Study

      Levy, Avner; Bell & Howell (International Foundation for Telemetering, 1978-11)
      A series of tests were conducted in an attempt to study the recording behavior of Enhanced Nonreturn to Zero (ENRZ) code at high linear recording densities. Using the "eye" pattern as a criteria in the first phase, the tests clearly demonstrate the sensitivity of a tape recorder to the DM (Delayed Modulation) coding technique as compared to ENRZ. For the same linear density, ENRZ has a considerably wider margin than the DM code. In the second phase of that study, a series of tests were conducted using high energy tape and magnetic heads with reproduce gaps in the order of 12 μin, referred to as "double bandwidth heads." Using present day technology, it was possible to demonstrate linear packing density never before achieved on magnetic recording tape.
    • High Performance Circulators, Isolators and Electronic Waveguide Switches

      Piotrowski, Wieslaw S.; TRW Defense and Space Systems Group (International Foundation for Telemetering, 1978-11)
      This paper presents the results of a most recent high technology development program that has led to significant state-of-the-art advances in the design and development of circulators, isolators and electronic waveguide switches at microwave and millimeter wave frequencies. These components are constructed by the use of an analytical design procedure. They are characterized by excellent electrical and environmental performance and feature a simple mechanical configuration, which results in significantly reduced prices. These units are presently commercially available from Aertech Industries, Sunnyvale, California, a TRW subsidiary.
    • High Speed A/D Converter Technology Survey

      Hobrock, L. W.; TRW Systems (International Foundation for Telemetering, 1978-11)
      Surveyed are current and future high speed A/D technologies with potential for a significant impact on future systems. Current bipolar silicon monolithic quantizers and hybrid sample-and-hold circuits are described. The gallium arsenide integrated circuit technology, including FETs and TEDs, provides speed increases from 10 to 100. Josephson Junction devices are discussed as a technology potentially offering radical increases in sample rates and reductions in power.
    • A Hybrid Data Compression Algorithm for Image Telemetry

      McCaughey, Dennis G.; University of Arizona (International Foundation for Telemetering, 1978-11)
      This paper presents an image coding algorithm using spline functions that is competitive with the more conventional orthogonal transform methods at data rates of 1 bit/pixel or less. Spline coding has the added attraction of an optical implementation arising from the fact that least squares image approximations also produces least squares approximations to the image derivatives. A first order spline is used to approximate the proper order derivative of the image whose order is determined by an analysis presented in the paper. The image derivative is then encoded and transmitted to the user who reconstructs the image by a k-1 order integration which can be done optically.
    • Hybrid Packet and Circuit Data Networks: Design and Operation Issues

      Gerla, Mario; University of California, Los Angeles (International Foundation for Telemetering, 1978-11)
      Experience with packet switching during the past decade has shown that the packet technology is very cost effective for bursty communications between computers and terminals. However, for applications characterized by a steady instead of bursty flow of information (e.g., file transfer, digitized speech, facsimile), it has been established that pure packet protocols are often inadequate because of the unnecessarily high line overhead and the high delay fluctuations between consecutive packets [1]. For such applications, a circuit switching approach (either physical or virtual) appears more advantageous [1],[2]. In the physical circuit approach, bandwidth is dedicated to a connection for the entire duration of the session; while in the virtual circuit approach the path is fixed at the beginning of the session and some expected bandwidth is guaranteed, in a statistical sense, along the path (but no physical bandwidth is assigned).