• 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).
    • Image Quality Considerations of Compressed Video Imagery

      Pearson, J. J.; Millman, M. W.; Maitra, S.; Lockheed Palo Alto Research Laboratory (International Foundation for Telemetering, 1978-11)
      Most work to date on image data compression has been based on single static images and the use of mean square error (MSE) as an objective quality criterion. However, many current requirements for video bandwidth compression, such as Remotely Piloted Vehicle and "smart" ordnance video links, include dynamic (moving) scenery and severe channel noise. The image degradation effects of the bandwidth compression technique will then fall into three categories: Degradation of a static image; effects due to any frame segmenting and partial frame transmission used; and the impact of uncorrected channel errors. In this environment, the more powerful, but also more complex techniques, i.e., the various transform techniques, may provide less acceptable imagery than simple techniques (such as DPCM or Lockheed's CAQ algorithm) since their complexity may require frame slicing, i.e., the compression and transmission of only a segment of a frame during each frame period. Also, the one-dimensional techniques often prove more effective than twodimensional techniques because the vertical redundancy they retain can be used to eliminate uncorrected errors. The MSE criterion for image quality, known to be crude and often misleading in static images, is totally inadequate to quantify the impact of scene dynamics and uncorrected channel errors.
    • The Impact of LSI on Telemetry Systems

      Finn, W. J.; Karwoski, R. J.; TRW LSI Products (International Foundation for Telemetering, 1978-11)
      Any system which measures, transmits over a distance, receives, and processes signals can be defined as a telemetry system. Video transmission systems, satellite communications systems wideband data links, and TDM/FDM transmultiplexers all have one thing in common: an increasing need for high-speed digital signal processing. This paper is intended to serve as an introduction to the application of LSI to telemetric signal processors.
    • Impact of Microcomputers on Telemetry and Telecommunications

      King, J. B.; Flight Systems, Inc. (International Foundation for Telemetering, 1978-11)
      The next computer revolution is under way. The first computer revolution impacted government and big business; the current revolution is affecting small businesses, schools and homes. The demands that will be placed on the telemetry and telecommunications industry in the next decade are mind-boggling. New products, new techniques and new jobs must be developed to respond to that demand. This paper presents future applications of microcomputers in communications and what that portends for our society.
    • INTELSAT V Spacecraft Antenna Subsystem

      Jakstys, V. J.; Ward, H. T.; Ford Aerospace and Communications Corporation (International Foundation for Telemetering, 1978-11)
      Design and development has been completed on the Antenna Subsystem for the INTELSAT V Communications Satellite. The Communications antennas include two C-Band (transmit and receive) Hemi/Zone coverage antennas, two C-Band (transmit and receive) Earth Coverage antennas, two 11/14 GHz Spot Beam antennas and an 11 GHz Beacon antenna. The C-Band Telemetry and Command antennas consist of two directional beam telemetry (transmit) antennas, a dual-port toroidal beam telemetry antenna and two cardioid beam command (receive) antennas. The designs have been verified by measurements, and the test results indicate that all major performance requirements will be achieved.
    • Interleaving of Reed-Solomon Viterbi Concatenated Coding Channel

      Chu, Cecelia; Miller, Warner H.; Goddard Space Flight Center (International Foundation for Telemetering, 1978-11)
      In this paper, two interleaving schemes are discussed and several R-S code array synchronization configurations are investigated. A procedure for obtaining synchronization sequences, for the R-S code array, under specified conditions is suggested and it is followed by the identification of sequences with desirable properties. Several graphs are presented, e.g., false synchronization probability versus various bit error rates for the number of errors permitted, and also, the missed synchronization probability versus various bit error rates for number of errors permitted and for various lengths of synchronization sequences. For the interleaving schemes discussed there is no analytical advantage, with respect to array synchronization, for selecting one scheme over the other.
    • International Telemetering Conference Proceedings, Volume 14 (1978)

      International Foundation for Telemetering, 1978-11
    • The Karhunen-Loeve, Discrete Cosine, and Related Transforms Obtained via the Hadamard Transform

      Jones, H. W.; Hein, D. N.; Knauer, S. C.; COM-CODE, Inc.; Kansas State University; Ames Research Center, NASA (International Foundation for Telemetering, 1978-11)
      The Karhunen-Loeve transform for stationary data, the discrete cosine transform, the Walsh-Hadamard transform, and most other commonly used transforms have one-half even and one-half odd transform vectors. Such even/odd transforms can be implemented by following a Walsh-Hadamard transform by a sparse matrix multiplication, as previously reported by Hein and Ahmed for the discrete cosine transform. The discrete cosine transform provides data compression nearly equal to that of the Karhunen-Loeve transform, for the first order Markov correlation model. The Walsh-Hadamard transform provides most of the potential data compression for this correlation model, but it always provides less data compression than the discrete cosine transform. Even/odd transforms can be designed to approach the performance of the Karhunen-Loeve or discrete cosine transform, while meeting various restrictions which can simplify hardware implementation. The performance of some even/odd transforms is compared theoretically and experimentally. About one-half of the performance difference between the Walsh- Hadamard and the discrete cosine transforms is obtained by simple post-processing of the Walsh-Hadamard transform coefficients.
    • The LES-8/9 Telemetry System: Pt I, Flight System Design and Performance

      Sarles, F. W.; Helfrich, J. H.; McKenzie, P. F.; Roberge, J. K.; Massachusetts Institute of Technology (International Foundation for Telemetering, 1978-11)
      LES-8 and LES-9 are two experimental communication satellites designed and built for the Air Force by the M.I.T. Lincoln Laboratory. The on-board telemetry systems were designed not only to monitor the spacecraft on orbit but also to provide significant test support capability during subsystem development and spacecraft integration and test. Each system is configured in a distributed form, with remote Telemetry Input Converters (TICs) located in various subsystems communicating with a central Telemetry Output and Control (TOC). Salient features include 1) modular design of TICs permitting tailoring to specific subsystem requirements, 2) accurate analog measurement capability (.025% of full scale) over 140EC ambient temperature (-60°C to +80°C), 3) cross-checking of analog-to-digital converters via a high stability (50 microvolts) stepped calibration source, 4) flexible word allocation permitting late freezing of formats, 5) digital organization with individual parity check on each word, 6) sub multiplexing capability, 7) dual speed operation at 100 bps and 10-Kbps, and 8) downlink capability via a variety of rf links. Descriptions of overall operation and performance along with design considerations in critical areas are covered in detail.
    • The LES-8/9 Telemetry System: Pt II, Ground Terminal Design and Performance

      Helfrich, J. H.; Gjelsvik, A. M.; Rader, C. M.; Rogers, D. C.; Small, C. E.; Massachusetts Institute of Technology (International Foundation for Telemetering, 1978-11)
      The LES-8/9 telemetry ground terminal is a distributed system providing simultaneous reception of digitally encoded telemetry from both LES-8 and LES-9 satellites via S-band, K-band, and UHF downlinks at ground commendable rates of 100-bps and 10-Kbps. Antenna control and demodulation as well as frame synchronization and error detection are provided at a centralized facility, and resultant baseband telemetry is distributed in processed digital format over serial-data lines through a coaxial-cable distribution network. Comprehensive, realtime telemetry processing is provided by separately located minicomputers which provide alphanumeric data displays to a distributed network of standard TV-type video monitors. Telemetry is recorded directly in IBM compatible form under minicomputer control and selection, with post-processing performed at the IBM-370 Lincoln Computation Center. Additional real-time processing is also provided by dedicated panels portraying subsystem operations. Extensive operational software has been developed for evolving needs from initial satellite integration and test through post-launch operation and monitoring. These programs as well as the related hardware equipment and organization are described and traced through the course of the LES-8/9 project.
    • Location of Cross-Correlation Sidelobes of PN Sequences

      Gold, Robert; Robert Gold Associates (International Foundation for Telemetering, 1978-11)
      In this note, we show how the cross-correlation pattern of certain classes of linear PN sequences may be determined and described as a linear shift register sequence. Knowledge of the location of the correlation sidelobes may then be exploited in the application of these codes to spread spectrum communication systems. As an example of such an application, a characterization of the relative phase of a received code in terms of the pattern of cross-correlation sidelobes with a locally generated code is presented.
    • LSI Devices for Fault-Tolerant Spaceborne Computer

      Bennett, Charles; Raytheon Company (International Foundation for Telemetering, 1978-11)
      In order to meet the requirements for future satellite applications, a brassboard of an extremely reliable fault-tolerant spaceborne computer (FTSC) has been developed by Raytheon Co., Sudbury, MA., under the sponsorship of the USAF/SAMSO*. The requirements for the FTSC were high reliability, high speed, low power, high density and tolerance to space radiation environments. The reliability requirements were realized through several unique system and circuit concepts while the remaining requirements could only be realized through use of large-scale-integrated (LSI) circuit technology. An assessment of possible candidates for the LSI requirements for the FTSC was performed on available and emerging technologies. Once the candidate LSI technology was selected, a "proof-of-technology" program was instituted. The program included the development of a test chip to prove the operational characteristics of the technology and its producibility. Development of flyable prototypes of the FTSC using LSI devices is the final program goal.
    • LSI Hardware for Data Communications

      Comisar, Gerald G.; The Aerospace Corporation (International Foundation for Telemetering, 1978-11)
      A review is presented of some new, low-cost, easy-to-use hardware for interfacing small-scale digital systems to telecommunications and data link networks. Devices featured are binary serial interfaces, protocol controllers (including SDLC and HDLC), data encryption units (including the new NBS Federal Standard), modems, and information encoders. Compatibility with existing microprocessors and future trends are discussed.
    • Medical Applications to Communications Satellites

      Shamaskin, Robert B.; Veterans Administration (International Foundation for Telemetering, 1978-11)
      It is recognized that closed circuit television and other electronic linkages, properly employed to deliver needed information, can be useful tools in the practice of medicine, particularly in providing linkage between distant points. In some instances terrestrial interconnection is practical, as in the case of short distances between communicating points. However, as distances become greater, so do the costs. Therefore, alternative cost effective methods of transmitting television and other types of signals for biomedical purposes are being sought. The development of high powered communications satellites demands consideration and experimentation. Therefore, the Veterans Administration is conducting a series of experiments to determine if and how communications satellites can be employed for diagnostic, therapeutic, educational and administrative purposes.