• A Laser Link Operating at One Gigabit/Sec

      Boehmer, A. M.; TRW Systems (International Foundation for Telemetering, 1971-09)
      This paper describes the design of a 1 Gbps digital telemetry/ communication system achieving a probability of bit error of 10⁻⁶. The system is based on the use of near future (approximately 2 years) components and is suitable for use in satellite- satellite, ground-satellite, and aircraft-satellite links. Both the advantages and problems associated with the use of laser links are cited, and the techniques used in this system that make use of the advantages and overcome the problems are identified. Small packages and apertures are used to achieve high ERP (116 dBW), narrow beams with small apertures permit use of low prime power (170 watts total for laser), enormously greater link privacy and reduced susceptibility to counter measures is obtained, direct detection eliminates doppler search and tracking, and the small package size gives satellite systems multiple package possibilities. To obtain these advantages very narrow (5 p radian) operational beams must be acquired and tracked, point-ahead offset for relative terminal motions must be implemented, effects of atmospheric disturbances must be minimized if the atmosphere is in the link, and any repeater configurations must demodulate/remodulate because of lack of any laser system capability for frequency translation and amplification. The following unique features of laser systems as opposed to microwave cussed: requirements for acquisition and tracking point-ahead requirements, unique modulation types hand circular polarization, unique types of noise and background shot noise, elimination of doppler direct detection, ability of the receiving system on its receiving aperture, unique atmospheric propagation disturbances, and possibility of signal coding to remove the signal spectrum from the vicinity of the noise spectrum.
    • VHF/UHF Stellar Calibration Error Analysis

      Taylor, Ralph E.; Stocklin, Frank J. (International Foundation for Telemetering, 1971-09)
      A statistical error analysis is performed to determine the degree of uncertainty encountered when calibrating steerable VHF /UHF receiving antennas with the stellar calibration method. The analysis considers the propagation of precision error indexes. It is shown that an antenna gain calibration by the stellar method has a one-sigma (1σ) uncertainty of ±0.65 dB at 1440 MHz (L-band), and ±0.8 dB (1σ) at 136 MHz (VHF). Somewhat increased precision can be achieved by monitoring the antenna gain-to-noise temperature (G/T) ratio at a station; a worst-case uncertainty of ±0.4 dB (1σ) can be realized at both L-band and VHF. Finally, field test measurements of antenna gain, obtained at 136 MHz in the NASA space tracking and data acquisition network (STADAN), demonstrate an uncertainty of ±1.0 dB, or less, which effectively confirms the analytical result.
    • A Multispectral Scanner Data Decommutator/Processor for the Earth Resources Technology Satellite

      Waltz, Edward L.; Bendis Aerospace Systems Division (International Foundation for Telemetering, 1971-09)
      This paper describes the design of the telemetry decommutator/processor for multispectral scanner data to be returned by the first two Earth Resources Technology Satellites (ERTS). This unit, referred to as the Multispectral Scanner Tape Decommutator/processor (MSS TDP), is a versatile data handling system which accepts multipletrack tape inputs, providing output formats compatible with a multipletrack tape recorder or a single channel film recorder. The system is organized as a parallel processor, being capable of decommutating and formatting five spectral bands of digital video data. Synchronization and decommutation of skewed multiple-track data is performed with housekeeping and calibration data being transferred to a control computer. A six scan line buffer is asynchronously loaded and synchronously unloaded to remove data skew and reformat the video data. The unit includes a highspeed arithmetic processor which performs radiometric calibration of a single spectral band of video data prior to film recording. The primary function of the MSS TDP will be the processing of receiving site data tapes for conversion to film images.
    • A Technique for Measuring the Behavior of a Navigational Buoy

      Babb, Lowell V.; Wilmarth, Robert W.; Budridge, Gerald J.; Transportation Systems Center; U.S. Coast Guard (International Foundation for Telemetering, 1971-09)
      A prototype instrumentation package has been designed and fabricated to furnish quantitative information about the stability of an ocean navigational buoy. A total of fourteen electro-mechanical transducers were included in the package to yield attitude, acceleration, and mooring chain tension information about the buoy. By utilizing a six channel telemetry data system and a 4-channel command telemetry system, continuous data from selected sets of transducers were recorded and used to determine the types, sensitivities, and ranges of instrumentation best suited to this application. The number of telemetry channels chosen represents the "best guess" number required in the final program which will consist of five separate instrumentation packages. By integrating the two telemetry systems in the prototype unit, a flexibility of operation was realized that yielded large amounts of useful data at a minimal cost.
    • Preliminary Report on the Development of a Crystal-Controlled L-Band Artillery Telemetry Transmitter

      Richardson, J. F.; Harry Diamond Laboratories (International Foundation for Telemetering, 1971-09)
      Harry Diamond Laboratories (HDL) has a need for gun-rugged UHF telemetry transmitters for use in research and fuze testing programs. An in-house design program was started because of the specialized performance requirements for artillery electronics. This is the first status report on the effort. UHF transmitters are extremely sensitive to physical deformation because small dimensional changes produce reactance changes that can cause an appreciable change in frequency. Since ruggedized crystal-controlled oscillators limit the frequency shift to low levels and therefore permit early acquisition of artillery telemetry signals; a prototype transmitter was constructed to determine the degree of efficiency and compactness that could be obtained at L band. A compact 1510-MHz transmitter having an efficiency of 6 percent at an output power level of 160 mW is described. Physical dimensions are such that the transmitter can be readily potted in any artillery telemetry housing currently in use. Temperature compensation and gun ruggedization tests are currently in progress.
    • A Shock Hardened Delayed Transmission System for Transient Data Acquisition

      Bentley, R. D.; Fritz, R. L.; Sandia Laboratories (International Foundation for Telemetering, 1971-09)
      A shock hardened, delayed transmission PCM system for use in an artillery projectile instrumentation program is reported. The output of the projectile mounted PCM encoder is coupled to an MOS shift register memory to delay data transmission until projectile flight, thus eliminating the requirement for a real-time transmission link for in-barrel data. The capabilities to monitor both in-barrel phenomena and flight performance parameters are included. Windowing of the transient, in-barrel data is accomplished by threshold discrimination within the projectile mounted system. System design, operation and ground support requirements are discussed with flight test results presented.
    • High Density Digital Recording with Video Techniques

      Curtis, D.; Rolfe, J.; International Video Corporation (International Foundation for Telemetering, 1971-09)
      A digital recorder which writes or reads digital data at 8 megabits per second and has a storage capacity of 84 billion bits per reel of tape is described. The packing density is in excess of I million bits per square inch on conventional one-inch magnetic tape. The high packing density and transfer rate was achieved through the combination of phase-encoded digital electronics with a helical scan video transport. The use of the helical scan technique permitted extremely efficient utilization of the tape and permitted inclusion of other features, such as high-speed search (400 ips), individually addressable records, and self-threading and cartridge-loading capability.
    • Half Speed Recording with Ferrite Heads and High Energy Tape

      Price, R. L.; Youngquist, R. J.; Minnesota Mining and Manufacturing Co. (International Foundation for Telemetering, 1971-09)
      This paper describes the results obtained with several new techniques which are being used to extend the frequency bandwidth limits and the signal to noise ratios of instrumentation magnetic tape record/ reproduce systems. During the past decade, wideband magnetic tape information recording densities have advanced in several stages to the currently used 60 to 80 micro inch wavelengths. The new techniques described in this paper now make it practical to record and reproduce wavelengths in the order of 30 to 40 micro inches. This results in a frequency bandwidth of 1.0 MHz at a tape speed of 30 inches per second. In comparison with present wideband systems this means an improvement of 2X in bandwidth, or a reduction of tape speed by one half is now possible while maintaining approximately 20 dB broadband signal to noise ratio with a track width of .025 inches. This width provides 28 tracks per inch of tape width. This improved performance has been obtained by combining recent improvements in "High Energy" tape, narrow gap ferrite record heads and ferrite reproduce heads. Using a systems approach, electronic signal processing circuits have been developed which coordinate these improvements in tape and heads, resulting in optimized "high performance" record/ reproduce systems.
    • Performance Results for a Hybrid Coding System

      Hoffman, L. B.; NASA (International Foundation for Telemetering, 1971-09)
      Computer simulation studies of the hybrid pull-up bootstrap decoding algorithm hive -been conducted using a constraint length 24, nonsystematic, rate 1/2 convolutional code for the symmetric channel with both binary and 8-level quantized outputs. Computational performance was used to measure the effect of several decoder parameters and determine practical operating constraints. Results reveal that the track length may be reduced to 500 information bits with small degradation in performance. The optimum number of tracks per block was found to be in the range of 7 to 11. An effective technique was devised to efficiently allocate computational effort and identify reliably decoded data sections. Long simulations indicate that a practical bootstrap decoding configuration has a computational performance about 1.0 dB better than sequential decoding and an output bit error rate about 2.5 x10⁻⁶ near the R(comp) point.
    • Miniaturized, Micropower Biomultiplexer Telemetry System Fabricated Utilizing Hybrid Techniques

      Trezek, J. P.; Firstenberg, A.; General Dynamics; University of California (International Foundation for Telemetering, 1971-09)
    • Appendix A: Tenth Annual Report of the Telemetering Standards Coordination Committee

      Pruss, Hugh (International Foundation for Telemetering, 1971-09)
    • Implementation of Maximum Likelihood Decoders for Convolutional Codes

      Clark, George C., Jr.; Radiation Incorporated (International Foundation for Telemetering, 1971-09)
      Maximum likelihood decoding of convolutional codes is finding considerable application in communication systems and several decoders of this type have recently been built. These decoders implement an evolved form of a decoding procedure that was originally described by Viterbi in 1967. In this document we describe the problems of reducing the Viterbi algorithm to hardware, the various tradeoffs and compromises that must be made, and the short cuts that are available. In addition an interesting variation on the Viterbi algorithm is described which results in favorable implementation particularly at high data rates.
    • On the Selection of an Optimum Design Point for Phase-Coherent Receivers Employing Band-Pass Limiters

      Simon, Marvin K.; California Institute of Technology (International Foundation for Telemetering, 1971-09)
      In the design of phase-coherent receivers employing bandpass limiters, it is customary to specify system performance relative to its value at a fixed design point. For a given design point, it is well known that an optimum tradeoff can be found between the power allocated to the carrier and sideband signals. This paper describes an attempt to further improve the performance of such coherent carrier systems by optimizing the design point based upon a given practical optimization criterion. The single-channel system is treated in detail and a brief discussion is given on how to extend the optimization technique to a two-channel system.
    • Electrocardiogram Transmission, the State of the Art

      Firstenberg, A.; Huston, S. W.; Olsen, D. E.; Hahn, P. M.; University of California (International Foundation for Telemetering, 1971-09)
      A comparative analysis of available clinical EKG telemetry systems was conducted. Although present day electrocardiogram diagnosis requires a high degree of measurement accuracy, there exists wide variations in the performance characteristics of the various telemeters marketed today necessitating careful consideration of specifications prior to procurement. The authors have endeavored to provide the physicians with a clear understanding, in terms of the effects on the electrocardiogram, of the factors he must evaluate in order to ensure high fidelity EKG reproduction. A tabulation of comparative parameter values for each unit obtained from manufacturers' specifications and substantiated by standardized performance tests conducted in our laboratory is presented.
    • A System for Radiotelemetry of Blood Pressure, Blood Flow and Ventricular Dimensions from Animals-A Summary Report

      Franklin, Dean; Patrick, Thomas; Kemper, Scott; Vatner, Stephen; Scripps Clinic and Research Foundation; University of California at San Diego (International Foundation for Telemetering, 1971-09)
      A practical system for measurement and radiotelemetry of blood pressure, blood flow and ventricular diameter in conscious, normal animals has been developed and is in routine usage in studies of normal and pathological cardiovascular responses to such perturbations as exercise. The general features of the system, the system specifications and the system limitations and applications are summarized.
    • Two-Way Coherent Tracking Systems

      Lindsey, William C.; Yuen, Joseph H. (International Foundation for Telemetering, 1971-09)
      This paper presents results pertinent to the development of nonlinear theory of two-way tracking system. In particular, the model of cascaded systems is presented and approximations to steady state probability density functions (p.d.f.'s) of the two-way system phase and Doppler error are given. From these certain numerical results required in the design and planning of systems are given.
    • Coherent Demodulation of Continuous Phase Binary FSK Signals

      Pelchat, M. G.; Davis, R. C.; Luntz, M. B.; Radiation Incorporated (International Foundation for Telemetering, 1971-09)
      This paper gives achievable bounds for the probability of error of continuous phase binary FSK signals on the white gaussian noise channel. Phase continuity, like convolutional encoding, introduces a dependence between adjacent transmitted signals which can be used to advantage in the demodulation process. It is shown that continuous phase binary FSK can provide a given probability of error with 0.8 db less signal-to-noise ratio than antipodal PSK. The paper also shows how the ideas developed for decoding convolutional codes apply to the demodulation of continuous phase FSK with rational deviation ratio.
    • The General Peculiarities of Animal Telemetry

      Cochran, William W.; Illinois Natural History Survey (International Foundation for Telemetering, 1971-09)
    • Small Animal Telemetry - An Overview

      Davis, Stanley D.; Case Western Reserve University (International Foundation for Telemetering, 1971-09)
    • International Telemetering Conference Proceedings, Volume 07 (1971)

      International Foundation for Telemetering, 1971-09