• An Adaptable Spacecraft Telemetry System

      Maxwell, Marvin S.; Silverman, Joseph R.; Czarcinski, Eugene A.; Goddard Space Flight Center (International Foundation for Telemetering, 1965-05)
      Because of the limitations of hardwired telemetry systems, existing spacecraft are denied the capability of revising their sampling structure, their sampling rates, or the experiments and/or test points to be sampled. A centralized system to provide these capabilities is described in this paper. This system is called the Flexible Automatic Computer Telemetry System (FACTS). As initially conceived, the FACTS, through the use of a stored program, will be able to sample a large number of channels with great flexibility in sampling rates, sampling structure and the selection of experiments and/or test points. This paper outlines the basic spacecraft and ground station system and illustrates the flexibility which can be achieved with it. Selected diagrams are given along with a description of the operation of the various units in the system.
    • An Advanced Integral Missile Evaluation System

      Mayo-Wells, Wilfrid J. (International Foundation for Telemetering, 1965-05)
    • Analysis of FM/FM Transmission Line Distortion

      Mohnkern, Gerald L.; N.A.S.A. (International Foundation for Telemetering, 1965-05)
      An IBM 1620 computer was programmed to evaluate the effects which the variation of propagation velocity and attenuation in coaxial cables has on a frequency modulated carrier. For a nine mile length of RG-8A/U the distortion of 70kc modulation on a 1 mc carrier was severe, while for a 10 mc carrier the distortion was negligible. A typical system using 4, 6, and 9 mc carriers on a single cable was evaluated.
    • Application of a Digital Computer to Real-Time Telemetry Systems

      Reinen, Gerald; Cox, Fred B.; Beckman Instruments (International Foundation for Telemetering, 1965-05)
    • Application of a Telemetry System using DSB-AM Sub-Carriers

      Roche, A. O.; Dynatronics, Inc. (International Foundation for Telemetering, 1965-05)
      The advantages of the DSB-AM subcarrier for wideband telemetry requirements have been discussed in previous papers. The purpose of this paper is to consider the specific performance of an FM telemetry r-f link when modulated by a frequency multiplex of DSB subcarriers. The performance is evaluated by constructing an appropriate model of the subcarrier multiplex based on a predicted noise power spectrum at the r-f demodulator output. The model is used to specify the individual subcarrier amplitude values that constitute the baseband signal, which will modulate the FM transmitter. The carrier power required to produce a useful signal-to-noise ratio at the outputs of the individual subcarrier demodulators is considered in general. The relationship between the degree of transmitter deviation, receiver bandwidth and the carrier power is derived. The carrier power required for operation over typical test range distances is determined in terms of the appropriate variables. The performance of two specific examples is calculated to illustrate the use of the several formulae that are derived. The examples also serve to relate and compare the performance of the DSB system configurations to the more traditional applications. Finally, the advantage of using increased r-f bandwidth is discussed.
    • A Class of Digital Transducers Utilizing Magnetic Recording

      Pear, Charles B.; Radiation, Inc. (International Foundation for Telemetering, 1965-05)
      The need for direct digital transducers has been recognized for some time but remains largely unsatisfied. Magnetic recording could be applied for many applications. In this paper the techniques, capabilities and limitations of magnetic recording for measurement purposes are discussed including resolution and flux responsive readout methods. Some of the classes of variables which might be measured are outlined.
    • Communications and Command for a Nuclear Lunar Power Plant

      Morris, Vernon B., Jr.; Hanson, William A.; Somers, G. William; Westinghouse Defense and Space Center (International Foundation for Telemetering, 1965-05)
      Extensive lunar exploration will require the establishment of relatively long-term lunar bases. The power demands and the high fuel transportation costs to support these bases will necessitate the utilization of nuclear power plants. In the following paper, the lunar exploration base is briefly described. The economics of electrical power production on the Moon are discussed and the need for a nuclear power plant is established. A power plant configuration is shown. Communications and command requirements are presented and the communications and command system is described.
    • Communications from a Mars Entry Probe

      Turner, Lester; Scientific Data Systems, Inc. (International Foundation for Telemetering, 1965-05)
      A low risk experiment to determine the principal properties (density, pressure, temperature) of the Martian atmosphere has been studied. A. slender conical capsule is ejected from the Mars fly-by or orbiting spacecraft and enters the planet’s atmosphere. Theoretical and experimental data support the concept of continuous communication between the sharp cone capsule entering the Martian atmosphere and the spacecraft. The communications system basically consists of a 25 watt transmitter phase modulating a 100 mc carrier on the entry capsule and a wideband receiver on the spacecraft. Transmitting power and spacecraft data storage considerations resulted in a data transmission rate of 147 bits per second in a pulse code modulated format.
    • Conditioning and Recovery of Aircraft Position Signals Through an Existing Data Link

      Kashar, A.; Kearfott Division, General Precision Aerospace Group (International Foundation for Telemetering, 1965-05)
      A Signal Data Converter system records aircraft present po t on and altitude data on film and also displays this data in a ground shelter, allowing for real time surveillance by a ground observer. This is accomplished by adapting a unique digital data transmission system to an existing infrared video data link.
    • Design and Performance of a New S-Band Transmitter

      Swartley, Richard H.; Eitel-McCullough, Inc. (International Foundation for Telemetering, 1965-05)
      This paper describes a telemetry transmitter designed for the 2.2-2.3 Gc band. Design philosophy followed to achieve minimum size, wide deviation capability, high reliability and high efficiency are discussed in detail. The paper presents extensive measured data to indicate achievement of design goals set by IRIG 106-60 and ARTC-34. Construction details of the transmitter are illustrated.
    • Design Considerations in Pre-D Receiving and Recording Equipment

      Swanson, E. E.; Defense Electronics, Inc. (International Foundation for Telemetering, 1965-05)
      Design factors to be considered in wide band Pre-D recording and playback equipment for usage in a versatile Pre-D system are presented. These design factors are introduced in a discussion of both the down-translator and up-translator. The mechanisms which produce spurious outputs from the up-translator and the effects caused by these spurious outputs are treated in detail. The extension of Pre-D techniques to FM Electronics equipment is covered.
    • A Dual Polarized, High-Power Synthetic Conical Scan Tracking System

      Chadwick, George G.; Homola, James A.; Hansen, Marvin E.; Radiation Systems, Inc. (International Foundation for Telemetering, 1965-05)
      The dual polarized high-power synthetic conical scan tracking system was designed for operation over the frequency range from 1700 to 2400 mc. This feed was developed for an existing 33' parabolic reflector which is presently located at the Floyd Test Site in Rome, New York. The feed network is located at the focal point of a parabolic dish and is fabricated in WR-430 waveguide. The system provides a horizontally polarized on-axis beam for transmission. It also provides two conically scanning receiving beams at a frequency different from the transmit frequency. One of the receiving beams is vertically polarized; the other is designed to receive the orthogonal horizontal polarization. The conical scan is synthetically generated and individual channel control is provided to allow the two receiving beams to be aligned. The feed system may be converted to provide monopulse outputs by simply removing the synthetic conical scanning mechanism.
    • Envelope Delay in a Tape Recorder System

      Starr, Jack; Ampex Corporation (International Foundation for Telemetering, 1965-05)
    • Evaluation of an Expanded FM/FM Baseband Structure

      Campbell, E. B.; Herbert, W. R.; Electro-Mechanical Research, Inc. (International Foundation for Telemetering, 1965-05)
      An experimental evaluation program was undertaken to investigate the feasibility of expanding the IRIG (Inter-Range Instrumentation Group) FM/FM baseband. The results of the evaluation indicate that with typical field equipment, three higher-frequency proportional-bandwidth channels can be added to the baseband while maintaining adequate system performance.
    • F. M. Capture Performance - Characterization and Measurement

      Baghdady, Elie J.; Gutwein, Joseph M.; ADCOM, Inc. (International Foundation for Telemetering, 1965-05)
      The effects of interference and capture in FM reception are reviewed for the purpose of determining the basis for characterizing and measuring the capture performance of FM receivers. Capture performance criteria and performance measurement techniques are proposed for application to FM telemetry receiver evaluation.
    • Five Basic Methods for the Generation of Binary Cyclic Codes

      Brothman, A.; Brothman, E. H.; Halpern, S. J.; Horowitz, L. M.; Miller, A. H. (International Foundation for Telemetering, 1965-05)
    • Flexible Communication System for Saturn

      Bruni, Donald J.; Davis, Donald G.; Dynaplex Corporation; N.A.S.A. (International Foundation for Telemetering, 1965-05)
    • Flutter and Time Errors in Magnetic Data Recorders

      Chao, S. C.; Ampex Corporation (International Foundation for Telemetering, 1965-05)
      Flutter and time errors are critical factors in all instrumentation recording. They become even more so in many current and future applications, especially in the data recovery and reduction processes of various telemetering systems. This paper presents analytically the relationship between flutter, time base error, and time base error difference (sometimes called jitter), plus the effects of these errors on direct and FM recording. Methods of measuring these quantities are discussed and experimental examples are given. Spectral and probability density analyses and measurements have indicated that these variables are basically random in nature, and as such, they should be specified in terms of a levels, rather than in conventional peak-to-peak figures. Finally, a measurement method for the typical values of interchannel time error is presented, and some trends of correlation among all channels are discussed.
    • Frequency Modulation Error Calculation

      Nyre, Donald L.; Douglas Aircraft Company (International Foundation for Telemetering, 1965-05)
      In a frequency modulation process, small amplitude sidebands near the deviation limits are sometimes distorted or lost. The problems and expense of preserving these lessor sidebands are often great, and spectrum space must be reserved for them. To date there appears to have been no clear statement of their importance in terms of data accuracy. This paper presents a numerical calculation of the errors accrued in a demodulated signal after truncation of the FM spectrum obtained with sinusoidal modulation. It is shown that the error increases for decreasing bandwidth. Error is evaluated for several bandwidths, and relationships to power outside the band are noted. Applications include specification of bandwidth for a given error in demodulated signal. The use of a limiter is assumed.
    • Frequency Spectrum of an FM/FM Signal

      Holt, J. C.; Douglas Aircraft Company (International Foundation for Telemetering, 1965-05)
      Several authors have attempted to derive a mathematical model that will describe the frequency spectrum of a FM/FM signal. However, to this author's knowledge, none of the mathematical models that have been published is valid when the carrier is modulated by more than one subcarrier. In this paper an expression for a FM/FM signal is derived that is valid when IRIG specifications are applied. Then this expression is manipulated into a form that will yield the frequency spectrum when the carrier is modulated by any number of subcarriers. Then an illustration of a two subcarrier frequency spectrum is presented.