• 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.
    • High "G" UHF Telemetry for Gun-Launched Sounding Probes

      Cruickshank, William J.; Ballistic Research Laboratories (International Foundation for Telemetering, 1965-05)
      The development of a UHF telemetry system that will withstand the high shock (50,000 g) of gun launched vertical sounding probes is described. The associated development of a ground based automatic angle and range tracking and receiving system using a modified AN/GMD-1A Rawin set is also presented.
    • High Data Capacity/High Environment Recorder

      Thompson, R. S.; Head, L. E.; Consolidated Electro-Dynamics Corporation (International Foundation for Telemetering, 1965-05)
      This paper describes an airborne digital magnetic tape recorder developed for use in high performance military aircraft. The main design efforts required to obtain a high data capacity under extreme environmental conditions while using a minimum of space are discussed, along with the results of the major environmental qualification tests.
    • International Telemetering Conference Proceedings, Volume 01 (1965)

      International Foundation for Telemetering, 1965-05
    • A Low Level Commutator with Field Effect Transistor Signal Gates

      Ely, William B.; General Devices, Inc. (International Foundation for Telemetering, 1965-05)
      A low level differential input commutator is described which uses field effect transistors for the signal gates. The commutator was built for airborne applications so that size, weight, and reliability were major considerations as well as electrical performance. Results are compared with commutators using other types of signal gates.
    • Matched Filter Systems in Rising Noise Spectrums

      Halpern, P.; Electro-Mechanical Research (International Foundation for Telemetering, 1965-05)
      It is common knowledge that the matched filters for signals in white noise have impulse responses whose time duration is exactly as long as that of the input signal. Nothing can be gained by extending the response of the matched filters to longer than one bit unless (1) the signal source is coded, or (2) the noise spectrum is rising or at least is other than white-Gaussian-ergodic. This paper discusses means of improving bit error rates without coding the source. There are essentially two ways of extending the integration time of the matched filters, each of which offers an improvement in signal-to-noise ratio. The first way is to extend the response directly to more than one bit but constrain the filter to give zero or some small pre-assigned intersymbol crosstalk. The second way is to build matched filters for multiple bits. Both techniques can be used simultaneously; i.e., matched filters can be constructed for bit patterns, and the responses can be extended to longer than the baud to which the filters are matched. Once again this extension is done under the constrain of zero or little crosstalk. In this paper, the matched filters for several examples are expanded in a rapidly converging series, each term of which is identifiable with a known network. For the cases where the shape of the noise is not known analytically, an experimental technique is given for determining sufficient statistics of the noise so that the optimum matched filters can be designed.
    • A Meteor Burst Telemetry System for a Nuclear Lunar Power Plant

      Swisher, B. F.; Johnson, R. E.; Boeing Company (International Foundation for Telemetering, 1965-05)
      The meteor burst telemetry system to be described was conceived, designed, and developed as an Engineering Model. The telemetry system will be used to telemeter oceanographic data from an experimental instrumented ocean buoy to be moored at continental shelf depths on Cobb Seamount to shore facilities at Seattle, Washington. Cobb Seamount is located in the Pacific Ocean approximately 300 miles off the coast of the State of Washington. A general description of the telemetry system and its operational characteristics, which are dictated by the statistical characteristics of the meteor burst mode of propagation, is presented. This is followed by a more detailed description of equipment elements of the system. The developmental status, the results of a propagation path field test, and plans for additional tests are discussed. Development results to date are sufficiently encouraging to generate confidence in the utility of a meteor burst telemetry system for oceanographic data acquisition.
    • Meteorological Rocket Telemetry in the 1680 Megacycle Band

      Drews, William A.; Walton, W. T.; Atlantic Research Corporation (International Foundation for Telemetering, 1965-05)
      A summary of the present state of design and a review of hardware currently in use and under development for meteorological rocket payloads is given. Important design parameters are discussed and the constraints imposed by existing ground support equipment are described.
    • A Microwave Telemetry Automatic Tracking Antenna

      Bejarano, Eduardo; White Sands Missile Range (International Foundation for Telemetering, 1965-05)
    • Miniature Telemetry Transmitter

      Wiley, J. R.; Busch, W.; Langan, L.; M.C.D. General Electric Company (International Foundation for Telemetering, 1965-05)
      The increased use of L and S-Band for telemetry services in conjunction with the need for miniaturized equipment, points up the desirability for compact transmitter units. This report describes a miniature S-Band transmitter and its associated power supply. The design goals are presented together with a discussion of the technical approach used to meet the severe requirements. Illustrations and performance data are included for completeness.
    • A Multiple-Beam Scanning Circular Array

      Chadwick, George G.; Glass, John C.; Hill, Jerome E.; Radiation Systems, Inc. (International Foundation for Telemetering, 1965-05)
      The geometry of the cylindrical array has always been appealing to system designers because of its ability to provide 360° of coverage. A technique will be discussed which allows a cylindrical array to provide high-resolution coverage over 360° of azimuth angle. When used as a scanning array, a beam may be swept through 360° by using any of the numerous techniques available for scanning a linear array. When used to provide multiple beams, an array of N elements is excited by N isolated inputs. Each input corresponds to a beam in a selected direction; all of the N beams being disposed uniformly over 360° of azimuth angle. In both the instance of the scanning array and the multiple-beam array, the resolution achieved is comparable to that available from a planar aperture of the same height and with a length equal to that of the cylinder diameter. The theory of operation for the cylindrical array is discussed in abridged form. Data are also presented for experimental four-, eight-, and sixteen-element cylindrical arrays.
    • A New Approach to Effective Digital Filter Design

      Duncan, P. H.; Douglas Aircraft Company (International Foundation for Telemetering, 1965-05)
      In this paper the effect of modifying digital filter weights derived on a least squares error basis through multiplication by certain weighting functions is investigated. It is shown that this approach amounts to adopting frequency resolution as a filter performance criterion, in a manner analogous to resolution in spectral estimates along the lines of Blackman and Tukey. Weight formulation using the method is very simple, and working transfer functions are easily estimated without computation. Simple, effective designs are presented for low, high and band-pass (or band-stop) filters of the "cosine" or in-phase type, for cosine "low low-pass" and "sampling" filters, and for "sine" or quadrature "sampling" filters, as well as differentiators.
    • A New Approach to Solid-State Communicator Design

      Schoenwetter, H. K.; General Devices, Inc. (International Foundation for Telemetering, 1965-05)
      An electronic commutator is described which employs only two types of modules and is expandable one channel at a time. Either high or low level commutators can be constructed. Data input circuits are completely isolated from gating voltages. Power per channel is 10 milliwatts; volume, 0.4 cubic inch. Commutator modules are suitable for air/spacecraft environments.
    • New Techniques in Telemetry Data Processing for the Apollo/Saturn S-II Program

      Moore, Paul D.; Frederickson, Water G.; North American Aviation, Inc.; Radiation Incorporated (International Foundation for Telemetering, 1965-05)
      The Apollo/Saturn S-II telemetry data processing systems are described from concept through development and fabrication. The systems are large-scale, dual computer-controlled systems that accept PCM, PAM, PDM, FM/FM, and FM data and are capable of processing raw data for display as time-history digital plots, tabulations, or oscillograph recordings. Stored-program decommutators which eliminate distribution patchboards for each data word are integrated into the system, thus, providing a flexible means of routing data with a minimum of human error. High-speed digital plotter/printers produce final annotated plots of selected channels for engineering reports, Small general-purpose computers are integrated in the system to establish data flow discipline. The computers function as an entry for operation control and for preparation and loading information to all programmable equipment, interconnecting digital equipment, process monitoring, and diagnostic testing of subsystem operation. Versatility of computer or manual systems control provides an optimum telemetry data processing environment. Advanced techniques are briefly discussed as related to these and other telemetry data processing systems.
    • A Novel PMCM System for Geophysical Research

      Toney, P. A.; Walter, J. M.; Dynatronics, Inc. (International Foundation for Telemetering, 1965-05)
      The concepts leading to development of an inexpensive digital data acquisition system employing novel Pulse-Morse Code Modulation and providing accuracy comparable to that of PCM are discussed. The several system-level and circuit-level considerations permitting the complete elimination of separate signal conditioning equipment and receiving-site synchronization, recording and processing equipment are presented. Finally, there is a brief commentary on future applications of the device and suggestions for related work.
    • The Operational Pre-D for the Atlantis Missile Range

      Shollenberger, George D.; Defense Electronics, Inc. (International Foundation for Telemetering, 1965-05)
      This newly-developed receiving and predetection recording system currently being integrated into the Atlantic Missile Range should prove of considerable interest to the telemetry systems engineer. The system, designated TRKI-12, will become part of the familiar "Range Rehabilitation Program." The TRKI-12 is capable of handling up to twelve simultaneous telemetry signals of any known or projected telemetry format. Frequency-translation methods used enable recording and reproduction of high bit-rate PCM and other wide-bandwidth signals with minimum distortion. A wideband FM recording method gives true DC to 500-kc bandwidth recordings. The system incorporates a diversity reception and combining concept enabling optimum combination of telemetry data from diversity antenna systems without undesirable byproducts or need for special phase-correction. The description herein, which includes design constraints and limitations for a system of this type, should yield information of concern to the range user and should be especially useful in establishing efficient and economical range interfaces.
    • An Operational Test Instrument for PCM Bit Synchronizers/Signal Conditioners

      Cumings, R. G.; Davies, R. A.; Defense Electronics, Inc. (International Foundation for Telemetering, 1965-05)
      The application for a device which will effectively test a PCM bit synchronizer/signal conditioner is described. The general requirements for a bit synchronizer analyzer are listed and some of the problems in implementing these requirements are discussed, including some problems relating to PCM signal conditioners. A description of an instrument capable of performing the required measurements is given.
    • Optimization of Potentiometric Type Pressure Transducers

      Welsh, Luther; Marks, Eugene A.; Bourns, Inc. (International Foundation for Telemetering, 1965-05)
      Potentiometric pressure transducer designs can be optimized to allow application of a given model or family to a very wide range of pressures with consistently low static error band. Analytical and empirical design relationships are developed and correlated to suggest specific optimization techniques.