• 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.
    • Digital Filtering Techniques for X-Ray Image Enhancement

      Hall, E. L.; University of Missouri-Columbia (International Foundation for Telemetering, 1971-09)
      Image enhancement techniques are designed to improve image quality for human viewing and are especially important in X-ray imaging systems since radiation levels must be minimized. Recursive spatial digital filtering and gray level transform enhancement techniques which may be implemented with small memory requirements and fast computation times will be described. A comparison of computations shows that this method is competitive with fast transform methods in terms of the number of computations and advantageous in terms of memory requirements. The most common method for evaluating enhancement results is subjective human evaluation. An experimental comparison of subjective evaluations and some objective measurements for a series of chest X-rays illustrate the evaluation problem and a possible solution.
    • High Data Rate Coding for the Space Station Telemetry Links

      Lumb, D. R.; Viterbi, A. J.; NASA; Linkabit Corp. (International Foundation for Telemetering, 1971-09)
      This paper summarizes a study of coding systems for high data rates with potential application to the space station telemetry links. Among the approaches considered were convolutional codes with sequential, Viterbi and cascaded Viterbi decoding. It was concluded that a high-speed (.40 Mbps) sequential decoding system best satisfies the requirements for the assumed growth potential and specified constraints. Trade-off studies leading to this conclusion will be reviewed. Some sequential (Fano) algorithm improvements will be discussed as well as real-time simulation results.
    • Design of a Memory Controlled PCM System

      Temkin, B. M.; Sherlin, R. E.; General Dynamics Corporation (International Foundation for Telemetering, 1971-09)
      Airborne PCM Telemeters are essentially alike in that they multiplex digital and analog data from numerous sources and format it into a serial data stream. Because of radical format differences in data requirements, however, frequent redesign of format generation logic is mandatory. The recent development of small non-volatile Read Only Memories with large bit capacities has suggested a telemeter whose characteristics can be altered merely by replacing a memory. The authors solution to the problem of the "universal encoder" is the design of the MPS-101 whose word format is controlled by a MOS-FET Read Only Memory. The MPS-101 can store six reasonably complex formats in its 6144 bit plug-in memory card. To insure flexibility, a bit rate oscillator and a premodulation filter are included within the interchangeable module. A program plug enables the user to address (select) the desired format, control the word size, select parity and vary the bit rate. Data rates can be clocked up to 750 KB/S, with no effect on system accuracy. This work has resulted in an encoder whose format is totally arbitrary and whose data structuring and major/minor frame synchronization techniques are strictly under "software" control. This work was performed under Sandia Laboratories Contract Number 72-3233.
    • Investigation of a PAM Tester Using PN Waveforms

      McClellan, Wade C.; Nicholas, M. H.; White Sands Missile Range; Duke University (International Foundation for Telemetering, 1971-09)
      A PAM tester using a shift register generated sequence and a conventional data (PCM) bit synchronizer and detector for synchronization was investigated. It was found to function satisfactorily with and without predetection tape recording. This tester can be implemented by adding digital-to-analog converters (DAC's), an error gate, and a rms voltmeter to a PN PCM tester which uses a shift register to generate the PN sequence.
    • 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.
    • Appendix A: Tenth Annual Report of the Telemetering Standards Coordination Committee

      Pruss, Hugh (International Foundation for Telemetering, 1971-09)
    • 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)
    • Small Animal Telemetry - An Overview

      Davis, Stanley D.; Case Western Reserve University (International Foundation for Telemetering, 1971-09)
    • FM/FM Telemetry of Physiological and Force Data During Military Parachuting and During High Speed Aerial Tow

      Reid, D. H.; Doerr, J. E.; Martin, J. D.; Terry, D. M.; Naval Aerospace Recovery Facility (International Foundation for Telemetering, 1971-09)
      15- and 9-channel FM/FM physiological/force-field telemetry data acquisition systems utilizing microminiaturized signal conditioning modules, IRIG subcarrier oscillators and 220 or 1485.5 MHz transmitters have been utilized to monitor the responses of military test parachutists throughout intentional free-fall parachuting and continuously during highspeed (110-150 KIAS) through-the-air-tow by C-130 aircraft. No in-depth physiological studies of parachutists have previously been conducted and no reference to intentional aerial tow of humans was found in the literature. The objective is to provide better human engineered egress and retardation equipment for the aircrewmember, to describe parachutists physiologically, and to assess biomedical response to aerial tow so that mid-air retrieval systems can be developed for rescuing ejectees over enemy territory. Mean heart rate profile to parachuting exhibits a double peaked curve with the highest values near parachute deployment (157.7 BPM) and second highest rates near landing (155.7 BPM) compared with baseline values of 77.4 BPM one hour pre-jump. Respiratory rate more than doubles during the jump (32.1 BrPM) at deployment when compared with baseline conditions (15.6 BrPM). Total riser forces at parachute deployment average 1632 lbs (8.34 +G(z)), Preliminary air tow data indicate that heart rate increases linearly with speed to 150 KIAS. One subject, who averaged 131.5 BPM at landing during nine parachute descents, had heart rates of 128 BPM at egress during tow, 171 BPM at 110 KIAS, and 182 BPM at 150 KIAS. Thermistors and subjective data indicated no significant chilling after 14 minutes in the air-stream.
    • Space Station Communications Using Interplex Modulation

      Butman, S.; Lafrieda, J.; Timor, U. (International Foundation for Telemetering, 1971-09)
      This paper describes a new PSK/PM modulation scheme, called interplex, which reduces cross-modulation loss. The scheme can be implemented without significant hardware changes in existing systems, and can be incorporated into the Space Station Telecommunications system.
    • Clinical Biotelemetry

      Kilpatrick, David G.; Kilpatrick Associates, Inc. (International Foundation for Telemetering, 1971-09)
      Telemetry and telemetric techniques are of increasing significance in clinical medicine. Diagnostic data is acquired in this way for both manual and automated interpretation or processing. It has become practical to assemble clinical monitoring systems from non-custom equipment. Clinical biotelemetry is reviewed briefly, and a recent composite system is described in some detail.
    • Linear and Non-Linear Digital Processing

      Ranieri, G. C.; Uhran, J. J., Jr.; University of Notre Dame (International Foundation for Telemetering, 1971-09)
      Three basic discrete estimators, each of increasing complexity, are presented for extracting a random signal sequence from one which has been distorted by an additive white noise sequence. Closed form solutions are obtained by minimizing the mean square error, convergence properties are indicated and comparisons made. Several examples are given to indicate what typically can be expected in each case.
    • 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.
    • 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.
    • 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)