ABOUT THE COLLECTION

The International Telemetering Conference/USA (ITC/USA) is dedicated to the promotion and stimulation of technical growth in telemetering and its allied arts and sciences. It is the premier annual forum and technical exhibition providing telemetry specific short courses, technical papers from professionals and students, and exhibits of the industry’s leading companies. ITC/USA is sponsored by the International Foundation for Telemetering (IFT), a non-profit corporation dedicated to serving the technical and professional interests of the telemetering community.

This collection contains the proceedings of the eighth International Telemetering Conference, October 10-12, 1972. The conference, sponsored by the International Foundation for Telemetering, was held at the International Hotel in Los Angeles, California.

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Recent Submissions

  • RECORDER PARAMETERS AFFECTING BIT ERROR RATE

    McKelvey, G. R.; ITT-Federal Electric Corporation (International Foundation for Telemetering, 1972-10)
    Instrumentation magnetic tape is the primary storage medium employed to store PCM telemetry data representing billions of dollars of expended effort. Considerable data are lost in the recording and playback processes which could be retrieved through proper equipment alignments. The major contributors to the data losses are discussed, and the test methods used to determine the resultant loss for each factor are explained. It is shown that equipment alignment becomes critical as PCM bit rates approach one megabit.
  • DESIGN OPTIONS FOR FUTURE COMMUNICATIONS SATELLITES

    Dicks, J. L.; Systems Engineering Division of COMSAT (International Foundation for Telemetering, 1972-10)
    The INTELSAT global system of communications satellites in operation today is a development covering four generations of satellites. Starting with the INTELSAT I or “Early Bird” satellite launched in 1965, each succeeding satellite series has provided more capability by the introduction of new coverage areas or increased telephony and television capacity Today with the INTELSAT III and IV satellites in operation, service is being provided between earth stations around the world of a quality that meets all appropriate CCIR and CCITT requirements. In this paper, the global network is examined with a view to determining those technical factors that impact on the design options of communications satellites of the future. The factors and trends expected to influence future satellite designs and configurations are discussed. Specifically these are derived from analyses of the volume and the distribution in each ocean area of the system traffic, from analysis of the available modulation and multiple access techniques, from estimates of possible traffic growth rates for the time frames of interest, as well as from considerations of the availability of launch vehicles, of the present and future state of technology, of reliability and continuity of service requirements and of impact on earth station design and modifications.
  • RECENT DEVELOPMENT RESULTS ON THE HELIOS S-BAND COMMAND RECEIVER

    Heynisch, B.; AEG-TELEFUNKEN (International Foundation for Telemetering, 1972-10)
    By joint effort of the US and West Germany a Sunprobe will be launched by 1974 named HELIOS. In the Telecommunications Subsystem the Telecommand Receiver has a keyrole as Experiments have to be switched up to 2 AU distance from earth. The input power at the Receiver Equipment input terminal is -147 dbm with SNR of 6 db in 2 BL(o) = 32,5 Hz Loop Bandwidth. To achieve this sensitivity a Receiver in Phaselocked loop techniques with a low noise Preamplifier had to be developed. In cooperation and with consultance of well known US-Scientists it was possible to design and develope the S-Band Receiver up to the Qualifikation Model in less than two years. This report shall give a survey over concept and design of the receiver and some special experiences during development and integration tests.
  • A SINGLE CHANNEL COMMAND DETECTOR FOR DEEP SPACE MISSIONS

    Knapp, Siegbert; AEG-TELEFUNKEN Laboratories (International Foundation for Telemetering, 1972-10)
    AEG-TELEFUNKEN has developed a Single Channel Command Detector which will be used in the solar probe HELIOS. This command detector demodulates command data, PSK-modulated on a subcarrier with a symbol error-probability of less than 1x10^-5 at an input signal to noise ratio of 13,2 db per symbol-length. The command detector consists of two succeessive second-order phase locked loops and a matched filter. The subcarrier synchronizer loop tracks the 512 Hz subcarrier, the bitsynchronizer loop performs data-synchronisation and in contrast to former space concepts, requires no additional power. The matched filter correlates the input signal and its estimate, generated by the subcarrier synchronizer-loop. The integration over exact dataperiods is dumped by the bitsyncpulse. This command detector enables the HELIOS Receiver chain to demodulate command data with less than 1 error in 100 000 symbols over a distance of ~ 300 mill. km. Due to sophisticated digital decoding of the HELIOS Decoder, this error-probability results in 1 false command being executed in 64 years.
  • COMPARING BANDWIDTH REQUIREMENTS FOR DIGITAL BASEBAND SIGNALS

    Houts, R. C.; Green, T. A.; University of Alabama (International Foundation for Telemetering, 1972-10)
    This paper describes the relative, bandwidth requirements of the common digital baseband signaling techniques used for data transmission. Bandwidth considerations include the percentage of total power in a properly encoded PN sequence passed at bandwidths of 0.5, 1, 2 and 3 times the reciprocal of the bit interval, T(b). The signals considered in this study are limited to the binary class, i.e., each decision at the receiver yields one bit of information, in contrast to signaling schemes which encode groups of bits into a given signal amplitude, phase shift, etc. The study compares such signaling techniques as delay modulation (DM), bipolar (BP), biternary (BT), duobinary (DB), pair selected ternary (PST), and time polarity control (TPC) in addition to the conventional NRZ, RZ and BIΦ schemes. It is shown that several of the signals can be transmitted over channels which block frequencies below 10% of the bit rate and still lose less than 5% of the total signal power. Based upon the dual consideration of a large number of regularily-spaced level transitions to assure synchronization plus a minimum of bandwidth and no dc response, it is concluded that DM and PST are the best choices.
  • DIGITAL FM DEMODULATION TECHNIQUES

    Garodnick, Joseph; Goldmark Communications Corp. (International Foundation for Telemetering, 1972-10)
    Digital systems have been heavily emphasized over the past decade because of their intrinsic trouble free operation, multiplexed signal handling capabilities, and the complex processing techniques possible through the use of small special and general purpose digital computers. The digital evolution has also allowed system cability to increase, while size, cost and power consumption decrease. Functions previously deemed impossible to implement are now being constructed in production facilities. When digital techniques are used for source encoding in a wide band communications network (such as two-way CATV), information is transmitted and received digitally with Small error probalility compared to analog signals, especially when carriers and media take the form of cable, laser beams and fiber optics where line repeaters are used in lieu of amplifiers.
  • THE INTRODUCTION OF A DIGITAL COMPUTER ON BOARD ESRO SCIENTIFIC SATELLITES

    Perry, M. A.; EUROPEAN SPACE RESEARCH ORGANISATION (International Foundation for Telemetering, 1972-10)
    ESRO requirements for a stored program general purpose digital computer for use on board satellites are discussed, and a machine which fulfils these requirements is briefly described. This computer has an ADD time of 2.8 microseconds and uses a 16 bit word. Power consumption is estimated at 10.6 Watts and mass is expected to be below 5 Kg. The interface between the computer and the telemetry and telecommand system is discussed, and problems foreseen in reprogramming the computer in flight via the spacecraft telecommand link are briefly exposed.
  • TELEMETRY TRACKING OF SUMMER TRANSPLANTED ELK IN SOUTH CENTRAL WYOMING

    Weeks, Richard W.; Cupal, Jerry J.; Ward, A. Lorin; University of Wyoming, Laramie; U.S Department of Agriculture, Forest Service (International Foundation for Telemetering, 1972-10)
    Transplanting elk into regions where the native elk population is low is relatively common practice. Generally, these releases have been made in winter. This paper discusses the telemetry system developed for use on elk, and the behavior of elk transplanted during the summer. An optimum time for transplanting of elk appears to be during the rutting season.
  • REDUNDANT AREA CODING SYSTEM (REARCS)

    Maier, James L.; Gardenhire, Lawrence; Rome Air Development Center; Harris Intertype Corporation (International Foundation for Telemetering, 1972-10)
    Redundant area coding was proposed in an Air Force patent, James Maier inventor, to relieve the long integration time required to transmit a reconnaissance photograph through narrow-band communication circuits where upper limits of 4800 to 9600 bits/second prevail. Further development by Radiation Systems Division was funded by Rome Air Development Center’s Reconnaissance and Intelligence Division. Mr. Lawrence Gardenhire developed the analysis curves used. As redundant area coding was conceived, unimportant areas were reduced by applying different orders of resolution throughout one frame of imagery, by blanking redundant areas, or by applying encoding so one frame could consist of areas basically unchanged and areas coded to represent special land such as Forest or desert. What evolved were techniques of applying redundant reduction algorithms in both areas, producing a low/ high resolution picture. Where 3 to 1 reduction ratios were optimum for an average “busy” picture, reduction ratios exceeding 10 to I have been realized. A 9 x 9 inch, 2000 x 2000, 6-bit grey level picture that required 42 minutes to send at a 9600-bit/ second rate, or about 14 minutes for a 3 to 1 reduction, can now be sent in 5 to 6 minutes. A 10 to 1 reduction ratio makes transmitting imagery through existing ground circuits more of a reality and fulfills user requirements.
  • INTRA-ORAL TELEMETRY CONTROL FOR ORTHOTIC POWER SYSTEMS

    Bontrager, Ernest L.; Nickel, Vernon L.; Scott, Ian; Rancho Los Amigos Hospital; Micro Telemetry Systems Company (International Foundation for Telemetering, 1972-10)
    Electrically-powered arm braces have reached a stage of development sufficient to permit the restoration of arm motion to a severely paralyzed person. Although many functional tasks can be performed with these powered braces, the degree of function attained is still limited by the capabilities of the control system. Most functional orthotic controls presently in use are of a switch type which provide sequential off/on control of the orthesis. Extra-oral tongue operated switch controls are now used routinely, and, although they are easily fitted, inexpensive and reliable, still they do not provide the degree of control which is desirable. This paper describes the developmental work being done at Rancho Los Amigos Hospital on intra-oral telemetry control systems. The design of a tongue-actuated intra-oral telemetry control system to control the “Rancho Electric Arm” (a seven-degree-of-freedom electrically-powered arm brace) is described in detail. The system consists of 15 specially designed solid state strain gauge pressure transducers and an eight-channel digital transmitter mounted in a metal dental appliance. The control signals which are generated are telemetered to a receiver mounted on the patient’s wheelchair and are used to control the velocity of the respective arm brace joints. Patient tests with the system have shown that the telemetered signal is of sufficient quality to effectively control the “Rancho Electric Arm.” Although a patient has been fitted with a prototype intra-oral control unit, it must be clearly understood that the system has not yet been perfected to the point that it is a functional control system for patient use.
  • IMAGE PROCESSING OVER THE ARPA COMPUTER NETWORK

    Pratt, W. K.; Kruger, R. P.; University of Southern California (International Foundation for Telemetering, 1972-10)
    A Communication system has been developed by the University of Southern California for providing digital image processing services over the ARPA computer network. In this system a user at a remote site may have images digitized at the USC site and transmitted over the network, or the user may supply an image for precision display. Also, image processing programs may be executed on the U.S. C. image processing system using the VICAR image processing language.
  • DELTA MODULATION AND DPCM CODING OF COLOR SIGNALS

    Habibi, A.; University of Southern California (International Foundation for Telemetering, 1972-10)
    A simple yet efficient class of coding systems employed extensively in coding correlated sources is the DPCM and delta modulation systems. We will study the performance of the adaptive and the simple delta modulators at high sampling rates and will compare that to the performance of well designed DPCM systems. The results are obtained by simulating the coding systems on a digital computer and using them to encode the components of a color video signal.
  • EXPERIMENTAL COMPARISONS OF TELEVISION TRANSMISSION TECHNIQUES

    Perkins, F. A.; Proctor, J. A.; Harris-Intertype Corporation (International Foundation for Telemetering, 1972-10)
    The performance of a television transmission system is ultimately measured by the subjective judgment of the viewer. For different processing techniques, this subjective judgment may not agree with objective measures such as output signal-to-noise ratio. This is particularly true when comparing analog and digital techniques, since the nature of the noise and distortion is quite different. A number of analyses have compared various modulation and processing techniques on the basis of qualitative characteristics. This paper provides data for subjective comparisons of several analog and digital techniques. The cooperation of the NASA Manned Spacecraft Center in allowing use of equipment being built and tested for them is gratefully acknowledged.
  • APPENDIX A: Eleventh Annual Report of the Telemetering Standards Coordination Committee

    Pruss, Hugh; Telemetering Standards Coordination Committee (International Foundation for Telemetering, 1972-10)
    Since its beginning in 1960 the TSCC has for the most part concentrated its efforts in reviewing standards published by the Range Commanders Council, IRIG. These reviews and resulting recommendations occurred prior to formal publication or formalization of the standard. It is also gratifying to note that most of the recommendations made were accepted for adoption in the printing of the standards. In its desire to serve all facets of the Telemetering Community, the T. S. C. C. began looking into the activities of other established Governmental Agencies, besides the D. O. D., who might benefit from assistance in the form of specification reviews by the T. S. C. C.. Subsequently, the T. S. C. C. took a long "look around" and discovered that NASA, GSFC was concerning itself with tracking and data acquisition system standards as they relate to new DSN/NASA needs for the current and forthcoming Space & Earth Sciences experiments. An offer of assistance was presented to NASA, GSFC in July of. 1971 and this was subsequently accepted by letter dated 8 September 1971 from the NASA/GSFC Data Systems Requirement Committee, Advanced Data Systems Division, Mission and Data Operations Directorate.
  • ADAPTIVE LINE BY LINE ENCODER FOR IMAGE TRANSMISSION

    Algazi, V. R.; University of California at Davis (International Foundation for Telemetering, 1972-10)
    A simple adaptive algorithm is applied to the line by line encoding of images. Among its desirable properties the algorithm includes a control of encoding errors independently of the image statistics. This block transform encoder, because of its adaptive nature gives rise to non-stationary errors and end of block effects. Two methods are proposed to reduce these effects and thus improve the subjective quality of reconstructed images. The performance of the algorithm is image dependent and several illustrative examples are given.
  • DATA COMPRESSION FOR EARTH RESOURCES SATELLITES

    May, C. L.; Spencer, D. J.; TRW Systems (International Foundation for Telemetering, 1972-10)
    This paper concerns an information-preserving data technique which is applicable to multi-spectral imagery such as that obtained by earth-resources satellites. The requirements for data compression in such missions is discussed and a rationale is presented for the use of distortion-free information-preserving compression. The selected compression technique involves the use of the spectralspatial-delta-interleave (SSDI) algorithm, a form of DPCM, to eliminate gross spectral and spatial redundancies. This reduced data is then coded for transmission using either the Huffman or the Rice coding algorithms. The coding algorithms have been simulated using a portion of frame 3698 taken during the Apollo S065 experiment and, the results are presented. A parametric study presents the compression achieved by the SSDI-Rice algorithm as a function of block size and split-pixel mode used. Implementation considerations are also given.
  • SELF-CORRECTING DIFFERENTIAL PCM

    Anglade, P.; Hawkes, T. A.; Durand, J. J. (International Foundation for Telemetering, 1972-10)
    Differential PCM (DPCM) systems are characterized by an accumulation of transmission errors in the signal regenerated in the receiver. The use of a normalization procedure before transmission appears to permit suppression of these errors. This normalization must be carried out with respect to the limit value toward which the signal is evolving. The error reduction is not immediate, but is a function of signal value and signal activity. For constant signals there is no reduction. Reduction is more rapid the more widely the signal varies, and is also more rapid as the frequency of signal reversals increases. This method of coding requires adaptation to each application, since the basic quantization interval varies with signal magnitude.
  • AMPLITUDE-PHASE-KEYING WITH M-ARY ALPHABETS: A TECHNIQUE FOR BANDWIDTH REDUCTION

    Thomas, C. M.; TRW Systems (International Foundation for Telemetering, 1972-10)
    The spectral occupancy of transmitted digital data can be reduced by employing symbols from an M-ary alphabet. A modulation technique combining both amplitude and phase keying (APK) requires less peak and average power than M-ary PSK to achieve the same symbol error probability. Efficient signal set designs have been found by an empirical search of a large number of candidate sets with a comparison based on symbol error probability. New 8-ary and 16-ary designs are presented which outperform previously suggested designs on both a peak and average SNR basis. The bandwidth efficiency of the principal APK sets and PSK is presented as a function of alphabet size (4-ary to 128-ary) to illustrate the bandwidth-power tradeoff.
  • HOW DO YOU DEFINE BANDWIDTH?

    Scholtz, R. A. (International Foundation for Telemetering, 1972-10)
    All definitions of bandwidth have certain basic properties which make them true measures of "width". In this paper we show that different bandwidth measures are not interchangable, and note that bandwidth can be viewed as a measure of the number of dimensions added to the signal space per unit time. Methods of computing the transmitted power spectral density in a digital communication system are given and the dependence of the spectral density on the statistical structure of the information source is indicated by example. The paper closes with bandwidth comparison s for three common sets of binary telemetry signals.
  • L-ORTHOGONAL SIGNAL TRANSMISSION AND DETECTION

    Lindsey, W. C.; Simon, M. K. (International Foundation for Telemetering, 1972-10)
    This paper investigates the detailed capabilities and performance characterization of systems that employ L-orthogonal signaling techniques. L-orthogonal signals represent a unified set of signals wherein the polyphase and orthogonal (bi-orthogonal) signal sets are included as special cases. This fact is important since orthogonal (bi-orthogonal) and polyphase signaling sets r e present opposing forces as far as tradeoffs between error probability, energy - to-noise ratio, and bandwidth requirements are concerned. Bounds on the performance of the optimum receive r and the performance of various suboptimum (practical) receiver structures are given. Coherent and differentially coherent detection of differentially encoded signals re also pursued. Various comparisons and tradeoffs are made by means of numerical evaluation of the error probability expressions.

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