• THE ADVANCED OPLE FOR SEARCH AND RESCUE

      Morakis, James C.; Rupp, Walter; National Aeronautics & Space Administration; Patuxent Naval Air Test Center (International Foundation for Telemetering, 1973-10)
      The OMEGA Position Location Experiment (OPLE) was performed in 1967 by the Goddard Space Flight Center in order to demonstrate a position location and data collection system. OMEGA navigation signals were received at a remote site and retransmitted via a synchronous satellite to a ground processing center where data collecting and position determination was performed. Recent technological advances have made it possible to develop an Advanced OPLE system towards a global search and rescue application. This application generated some new problem areas such as the OMEGA lane ambiguity, random access, location accuracy, real time processing, and size and weight of the Search and Rescue Communication (SARCOM). This experiment will demonstrate the feasibility of instantaneous alarm and position location by using a relatively inexpensive, battery operated, three-pound package. This package can transmit the alarm and position through a synchronous satellite to a search and rescue station in less than three minutes, in an environment of 50,000 to 100,000 subscribers drawn from the maritime, aircraft, recreational communities and others.
    • A SHOCK HARDENED PCM SYSTEM WITH DATA STORAGE

      Barnes, D. E.; Sandia Laboratories (International Foundation for Telemetering, 1973-10)
      A miniature shock hardened PCM system with data storage capability has been developed by Sandia Laboratories for use in test where RF transmission either difficult or impossible. The PCM has 16 channel input capacity and encodes the data with 6 bit accuracy. The data rate is selectable from 1k bit per second to 250 k bit per second. The encoder has been harbarized and packaged in a volume of less than 4 cubic inches. The data storage is selected in 6 k bit increments with a maximum storage of 600 k bits. Typical applications involving earth and water penetrating are described.
    • A MULTI-PURPOSE, DUAL-CHANNEL MODEM FOR C/No THRESHOLD

      Baghdady, Elie J.; Info Systems (International Foundation for Telemetering, 1973-10)
      A description is given of a newly developed modem based on the synthesis of a constant-envelope quadra-phase signal with dual-channel frequencydivision multiplexing of analogvoice with data, data with data, time code With data, ranging signal with d:Ata, etc. The technique is capable of providing low-threshold operation down to carrier power-to-(noice power density) ratios, about 40 db, and includes a built-in, on-line measurement and display of the C/N(o) for quantitative performance monitoring purposes.
    • HIGH DENSITY PCM MAGNETIC TAPE RECORDING

      Wells, Jon B.; Bell & Howell (International Foundation for Telemetering, 1973-10)
      The Bell & Howell Enhanced-NRZ™ recording reproducing technique for bit packing densities up to 40,000 per track inch is described in this paper. Utilization of the pulse code modulation format of Enhanced-NRZ achieves this high density with a bit error rate of one in ten million. Bell & Howell’s standard VR-3700B instrumentation tape recorder and wideband instrumentation recording tape are used. This same technique permits parallel recording of data rates up to 10 megabits per second at a tape speed of 120 in./s. The merits of the unique encoding/decoding method, factors affecting bit error rate, and future opportunities for development are discussed.
    • RCC TELEMETRY STANDARDS

      Reynolds, R. Stanton; Range Commanders Council (RCC) Telemetry Group (International Foundation for Telemetering, 1973-10)
    • APPENDIX A: TWELFTH ANNUAL REPORT OF THE TELEMETERING STANDARDS COORDINATION COMMITTEE

      Muller, Ronald M.; TELEMETERING STANDARDS COORDINATION COMMITTEE (International Foundation for Telemetering, 1973-10)
      The Telemetering Standards Coordination Committee (TSCC) was formed in 1960 and has been in continuous operation since that time. It is now sponsored by the ISA and the ITC and its membership is drawn from a wide cross-section of the telemetering community. Thus the views of Government, industry, user and manufacturer are brought out when any standard is reviewed by the committee. In accordance with its charter the TSCC is charged with the following tasks: establishing what standards, methods, and procedures are in existence and published; examining the technical adequacy of existing and proposed documents; exploring the need for new standards, methods, and procedures and promulgating the derivation of new documents. The TSCC does not issue standards, but rather acts as a review, coordinating, and fact-finding body, endorsing specific standards, methods, and procedures, and making recommendations to the appropriate document originating groups, to telemetry users and manufacturers, and the Government agencies. For further information on the origination of the TSCC and its original Charter and Bylaws, please see the 1962 Proceedings of the National Telemetering Conference. An annual report has been published each year since that time. Years 1963 through 1967 may be found in the NTC Proceedings of that year and, starting 1968 and all following years, may be found in the Proceedings of the International Telemetering Conference.
    • TIME DOMAIN ANALYSIS OF AN AGC WEIGHTED COMBINER

      Hill, E. R.; Naval Missile Center (International Foundation for Telemetering, 1973-10)
      The conventional agc weighted diversity combiner is implemented on the assumption that the agc system of each receiver is tracking the rf fading envelope perfectly (i.e., such as to maintain the linear i-f output amplitude constant). The departure from optimum (maximal-ratio) combining which results from imperfect tracking is determined by computer solution of the nonlinear differential equation of the agc system for particular deterministic rf fading envelopes. The performance of the agc weighted combiner is compared with maximal-ratio and equal-gain combiners, both as a function of time and fade rate. It is shown that under certain conditions the equal-gain combiner outperforms the agc weighted combiner. It is also shown that by using both the a-m (detected linear i-f envelope) and the agc voltages for weighting the combiner the limitations arising from the response time of the agc system can be overcome. It is also indicated how an optimum diversity selector can be implemented by using both the a-m and agc voltages.
    • A HIGH CAPACITY, HIGH DATA RATE INSTRUMENTATION TAPE RECORDER SYSTEM

      Bessette, O. E.; Radio Corporation of America Recording Systems (International Foundation for Telemetering, 1973-10)
      A 240-megabit/second, serial bit stream recording system using a longitudinal (fixed-head) magnetic recording technique called HDMR (High Density Multitrack Recording) has been developed. This system provides maximum bits per square inch of tape at reliable in-track packing densities. Unique “unitized” fabrication techniques have been used to construct single stack magnetic heads (record/play on the same head) at track densities of over 100 tracks per inch. Commercially available tape is accommodated by the use of error detection and correction. HDMR technology, applied to the implementation of a typical ground instrumentation recording system, allows key performance parameters of: 240 Mb/s serial data input, 108 in/s tape speed, a 142-track head, a bit error rate of 1 x 10^-6 and 240 Mb/s serial data output.
    • USER-ORIENTED IMAGE DATA CARTRIDGE RECORDING SYSTEM

      Horton, Charles R.; Radio Corporation of America (International Foundation for Telemetering, 1973-10)
      New generation satellites such as ERTS present a new challenge to the data recording industry. Continuous wideband data creates an enormous storage/retrieval problem. Recently developed high density tape storage solves the volume problem but does not provide fast access. Clearly, some cartridge type device is required. A similar problem faced the broadcast T.V. industry. Cartridge equipment was developed to allow automatic programming of short segments. This paper describes application of this technology to present and future data storage requirements. With the technique described, ERTS data can be segmented into blocks of ten frames each and stored in easily accessed tape cartridges.
    • AIFTDS-4000, A FLEXIBLE HIGH SPEED DATA ACQUISITION SYSTEM

      Borek, Robert W.; Aeronautics and Space Administration (International Foundation for Telemetering, 1973-10)
      The data acquisition system of today’s research aircraft generally consists of a multiplicity of “black boxes” linked together by wiring cables of various lengths and sizes. This approach offers the user an “off-the shelf” type of flexibility to which he has become accustomed. It does not, however, provide for all the needs of an results demanded by today’s technology. The rising costs of flight test hours, the sophisticated airframes, and the minimum flight time allotted for actual flight test indicate a need to review existing data acquisition system technology and apply up-to-date technology. The NASA Flight Research Center at Edwards, California, initiated a review of its needs in the area of airborne data acquisition systems. The result was a new and powerful system called “AIFTDS-4000” (Airborne Integrated Flight Test Data System). AIFTDS is a high speed computer-controlled PCM system comprised of three basic units, the remote multiplexer de-multiplexer unit, the PCM processor, and the memory unit. The three units were designed and tested to meet the requirements of pertinent Mil-Specs for high performance aircraft. The signal conditioning, sensor excitation, and time code generator were designed as an integral part of the system and are not separate chassis. This paper discusses the design objectives established prior to actual hardware construction and compares these objectives with the final hardware.
    • SIMULATION RESULTS FOR AN INNOVATIVE ANTIMULTIPATH DIGITAL RECEIVER

      Painter, J. H.; Wilson, L. R.; National Aeronautics and Space Administration; LTV Aerospace Corp. (International Foundation for Telemetering, 1973-10)
      Simulation results are presented for the error rate performance of the recursive digital MAP detector for known M-ary signals in multiplicative and additive Gaussian noise. The structure of the digital simulation of the innovative receiver, operating in a multipath environment, is generally described. Specific results are given for a quaternary signal, of the type used in air-ground data links, with 2500 symbol per second transmission rate. Plots of detection error rate versus additive signal to noise ratio are given, with multipath interference strength as a parameter. For comparison, the error rates of conventional coherent and noncoherent digital MAP detectors are simultaneously simulated and graphed. It is shown that with non-zero multiplicative noise, the error rates of the conventional detectors saturate at an irreducible level as additive signal to noise ratio increases. The error rate for the innovative detector continues to decrease rapidly with increasing additive signal to noise ratio. In the absence of multiplicative interference, the conventional coherent detector and the innovative detector are shown to exhibit identical performance.
    • THE APPLICATION OF AEROSPACE TECHNIQUES TO AUTOMOTIVE CRASH TEST INSTRUMENTATION

      Jachman, J. J.; Ford Motor Company (International Foundation for Telemetering, 1973-10)
      The ultimate proof test of compliance with government safety standards for automobile “passive” occupant crash protection is obtained by crashing a test vehicle, occupied by instrumented anthropometric test dummies, into a concrete barrier. Each test of this type costs a minimum of $10,000, and much more if the vehicle is a prototype. The data that are obtained from the test dummies during such tests are the proof of compliance with the government safety standards and, therefore, must be highly reliable. Many aerospace techniques, such as a Metrology Laboratory, Quality Control, and redundancy can be adapted and utilized to maximize the reliability of the barrier crash data. These techniques are described and some early results are summarized. The early results show a marked improvement in data reliability compared to previous tests.
    • MECHANICAL DESIGN CONSIDERATIONS FOR A PROJECTILE TM

      Williams, Don, JR.; Sandia Laboratories (International Foundation for Telemetering, 1973-10)
      The mechanical packaging necessary to protect electronic packages from the gun firing accelerations is the key to a successful telemetry system. All components and wires must be given structural support, usually by the use of potting materials. Where the accelerations come from and two successful packaging methods are described.
    • ULTRASOUND TELEMETRY OF FETAL CARDIAC ACTIVITY

      Hess, Orvan W.; Litvenko, Wasil; Yale University (International Foundation for Telemetering, 1973-10)
      Patterns of alterations in fetal heart rate provide the earliest clue of jeopardy of the fetus from umbilical cord compression, abnormal uterine contractions, placental dysfunction or impaired fetal reserve. Correlated with uterine contractions, such patterns provide an index of the condition of the fetus and an objective basis for clinical management. The recognition of the value of continuous monitoring of these parameters has resulted in widespread use of electronic apparatus. Telemetry techniques have proved value as an alternative method of surveillance. A system has been devised for telemetry of fetal cardiac activity detected with ultrasound.
    • THE D.O.T. CHANNEL SIMULATION AND MODEM TEST FACILITY

      Buck, R. E.; Frasco, L. A.; Salwen, H. C.; Transportation Systems Center; Proteon Associates (International Foundation for Telemetering, 1973-10)
      The characteristics and capabilities of a channel measurement and simulation facility are described. This facility has been established at the U. S. Department of Transportation, Transportation Systems Center. The system employs a RAKE type channel measurement system and a compatible digital equivalent tapped delay line channel simulator. The equipment has been used for the evaluation of digital communications problems created by the urban environment. It is currently being used to investigate the performance of modems under a variety of propagation conditions.
    • A PROGRAMMABLE SAMPLING FORMAT TELEMETRY SYSTEM

      Peterson, Max B.; Johns Hopkins University (International Foundation for Telemetering, 1973-10)
      This paper describes the programmable sampling format telemetry system to be used by the near-earth Small Astronomy Satellite-C (SAS-C) and possible future SAS missions. The concept of the programmable sampling format is introduced and the features of the system are illustrated by an example. The SAS-C telemetry system is described at the block diagram level and redundancy of the system is discussed briefly.
    • THE DESIGN OF A SECOND GENERATION YAWSONDE

      Clay, Wallace H.; Mermagen, William H.; Ballistic Research Laboratories (International Foundation for Telemetering, 1973-10)
      Improvements have been incorporated into existing yawsonde telemeters to facilitate ground reduction of extensive quantities of data. The main area of improvement has been in the design of the amplifier so that solar pulses of constant amplitude and constant width can be transmitted to ground receiving stations. The new amplifier design makes it possible to reduce the solar pulse data on board the projectile itself providing solar aspect angle as a function of time of flight in binary coded form at the transmitter. Such on-board, real time motional data could be used in a command/control system to enhance the accuracy of artillery fire.
    • CRYSTAL-CONTROLLED HIGH-G TRANSMITTER

      Lange, Kenneth L.; Schell, Max V.; Hewlett-Packard; Sandia Laboratories (International Foundation for Telemetering, 1973-10)
      Continuous telemetering during and after a 10,000 to 16,000g shock pulse experienced by the telemeter is a requirement that is frequently not met. In most cases a free-running oscillator is used in the transmitter while a very wide band receiver is used to acquire and provide leeway for the drifting and shifting RF signals.
    • MULTIMEGABIT OPERATION MULTIPLEXER SYSTEM

      Giri, Ronald R.; Maxwell, Marvin S.; Radiation; Goddard Space Flight Center (International Foundation for Telemetering, 1973-10)
      The Multimegabit Operation Multiplexer System (MOMS) is a high data rate PCM telemetry unit capable of sampling and encoding 60 scanning radiometer and 4 vidicon channels at 250 kilosamples/second and 5 megasamples/second, respectively. This sampling capacity plus the 7-bit quantization requires a total throughput rate of 40 megasamples/second and 280 megabits/second. To produce these rates efficiently, the system was divided into a pair of identical 140-megabit blocks. A low-power 20-MHz analog multiplexer and analog-to-digital converter were developed together with a video sample-and-hold that features an aperture time error of less than 50 picoseconds. Breadboard testing of these basic building blocks confirmed the design prediction that the total system would consume 27 watts of power. Two 140-megabit output ports are suitable for quadraphase modulation.
    • COORDINATION OF TELEMETRY STANDARDS

      Muller, Ronald M.; Telemetering Standards Coordination Committee (International Foundation for Telemetering, 1973-10)