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 sixth International Telemetering Conference, October 13-15, 1970. 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

  • Quartz Crystals Units for High G Environments

    Bernstein, M.; U.S. Army Electronics Command (International Foundation for Telemetering, 1970-10)
    Quartz crystal units are commonly used to achieve frequency accuracy of the order of 100 parts per million or better. The usual crystal mechanical environments are quite benign compared with those encountered In high g telemetry, however, and the normal shock tests are only 100 g's. The preliminary, design of a ruggedized high frequency crystal unit is shown as well as test date on the behavior of these units when subjected to 15,000 g's of impact shock. A crystal resonator is quite fragile since at 20 MHz an AT resonator is only 3 thousandths of an inch in thickness. Higher frequency units appear to have a g limit only slightly in excess of 20,000 g's. At lower frequencies, the resonator is not the limiting element but the supports and bonds become unreliable. A trade-off must be made between a very stiff support, which will increase the acceptable g level, and the concomitant frequency instability due to changes in mechanical stress on the quartz resonator. These stress changes can be caused both by differential thermal expansion of the mount and quartz as well as by shock Induced effects.
  • Notch Noise Loading Data on Baseband Tape Recording

    Heideman, W. R.; Nichols, M. H.; Aerospace Corporation (International Foundation for Telemetering, 1970-10)
    Notch power ratio tests were performed on a magnetic tape recorder/ reproducer, using direct recording in the baseband. For the equipment tested, it is concluded that the IRIG method of setting the record power level as that which produces 1% third harmonic on a single tone, does not necessarily result in an optimum record/reproduce cycle. It is concluded that the input and output levels should be set with reference to notch noise test data to optimize baseband tape recording performance for baseband recording of frequency division multiplexed systems. In order to interpret the notch noise data, it was necessary to assume two non-linear processes, one acting in conjunction with the record process and one in conjunction with the playback process.
  • Performance Evaluation Medthos for PCM Bit Synchronizer/Signal Conditioners

    Peavey, B.; NASA/Goddard Space Flight Center (International Foundation for Telemetering, 1970-10)
    PCM Bit Synchronizer/Signal Conditioners (BSSC) possess 3 basic performance characteristics which directly affect the processing of PCM telemetry data. These characteristics are: bit error rate (BER), bit slippage rate (BSR), and bit sync acquisition (BSA). This paper describes proven methods to meaningfully, and accurately measure these characteristics with particular emphasis on BSR and BSA. These methods require relatively simple and inexpensive procedures and instrumentation, and could be used by manufacturers and users to evaluate and acceptance test BSSC. The basic principle employed in these methods is "fixed threshold frame synchronization" with a unique strategy. Thus, there is no requirement for bit delay between the reference and BSSC output data, and synchronization of the reference data in the comparator with the BSSC output data takes place automatically. Moreover, this approach to testing BSSC represents the actual situation in which the BSSC would be operating as part of the telemetry data system, and hence would provide a direct measure of system performance. In actual application, these methods proved to be very effective and accurate for input SNR of E(b) /N(0) > O dB, and slightly less accurate for E(b) /N(0) < O dB (data having more than 10% errors). In general, BSA and BSR measurement accuracies of 20-30 bits can be achieved. A detailed discussion of accuracy is presented in the paper. In addition, the BSR and BER measurement methods are applicable to assessing the performance of tape recorders (TR) as it affects the actual system performance, rather than just the peculiar TR characteristics of TBE (time base error), bit dropout, and wow and flutter.
  • Appendix A: Telemetering Standards Coordination Committee Report

    Gardenhire, Lawrence W. (International Foundation for Telemetering, 1970-10)
  • The Lunar Communications Relay Unit System Design

    Trachtenberg, B.; RCA Corporation (International Foundation for Telemetering, 1970-10)
    Lunar Surface Exploration by Early Apollo Astronauts was limited by the range capabilities and configuration of the surface communications. To permit greater scientific yield from manned lunar exploration, it was necessary to provide improvements in crew mobility plus communications compatible with extended extravehicular activity. Expansion of EVA and video communications capability was constrained by the requirement of interfacing with existing earth and lunar surface facilities, vehicle payload requirements, and crew operational considerations. Various trade-off s were conducted to permit rapid development of a feasible communication's system which are described herein. The revision of the EVA mission profile necessitated establishment of new signal design parameters compatible with mobile and fixed site relay configurations. The design approach selected required strict discipline to enable integration of the electrical, mechanical, thermal and human factor fields. The resultant design of the Lunar Communications Relay Unit is a portable communications package to provide relay-to-earth of voice, data and color television from lunar surface locations far beyond the LM landing site and relay of ground voice to the EVA crew.
  • Telemetry and Communications to Apollo Flight Controllers

    Glines, Alan; Lazzaro, Joseph A.; NASA Manned Spacecraft Center (International Foundation for Telemetering, 1970-10)
    The focus of this paper is on the use of telemetry and communications as essential tools in Apollo flight operations. The operational capabilities of the spacecraft and ground systems are described briefly to provide a background for detailing the management of the Apollo data system. The Mission Control Center is the central point of the operations and the recipient of all real-time Apollo data. Therefore, the operational structure within the mission operations control room is outlined briefly, with emphasis on the flight controllers who are the prime users and manipulators of telemetry data. The Instrumentation and Communications Officer (INCO) and the Operations and Procedures Officer (PROCEDURES) in the mission operations control room are responsible for the compatibility control of both the spacecraft and ground telemetry and communications systems. Their mission duties in four areas are detailed: (1) space-vehicle/ground communications compatibility, (2) telemetry subcarrier and bit-rate control, (3) spacecraft antenna management, and (4) data retrieval. The INCO and the PROCEDURES, through effective management of the many communications-systems modes of operation, maximize the amount of preferred real-time and playback data being transmitted to the Mission Control Center. The importance of the data is illustrated by specific mission events from the Apollo 11, 12, and 13 missions.
  • Manned Space Flight Network Telemetry System

    Underwood, Thomas C., Jr.; Goddard Space Flight Center (International Foundation for Telemetering, 1970-10)
    This paper discusses the Manned Space Flight Network (MSFN) Telemetry System as it has been developed through the Mercury, Gemini, and Apollo programs and is now being modified to meet Skylab, Earth Resources Technology Satellite (ERTS), and Apollo "J" mission (Apollo 16 and subsequent lunar missions) requirements. The existing telemetry system must be modified to meet the requirements of these future programs. This modification will consist of the implementation of automated configuration switching, centralized control of telemetry subsystems, tunable FM and PSK modulators/ demodulators, high frequency PCM signal conditioners, and the upgrading of both the wide band instrumentation magnetic tape recorders and the PCM decommutation capability. The resulting telemetry system, which will be capable of supporting various manned and unmanned space missions, is described here. Data flow diagrams are delineated and equipment electrical characteristics are discussed.
  • Manned Space Flight Network Unified S-Bond System 1970

    Spearing, R. E.; Goddard Space Flight Center (International Foundation for Telemetering, 1970-10)
  • Signal Designs for Apollo Scientific Data Systems

    Hood, B. H., Jr.; Dawson, C. T.; Loch, F. J.; NASA Manned Spacecraft Center (International Foundation for Telemetering, 1970-10)
    The Apollo lunar-exploration missions are being planned for the purpose of obtaining comprehensive scientific data. The system descriptions and key signal-design considerations for two data transmission systems - the Phase II Scientific Data System and the Particles and Fields Subsatellite - are discussed. In both cases, the designs are constrained by the requirements to (1) use the existing spacecraft systems where possible, (2) use the existing ground stations, and (3) maintain the existing Apollo communications capabilities.
  • Apollo Lunar Communications

    Sawyer, Ralph S.; NASA Manned Spacecraft Center (International Foundation for Telemetering, 1970-10)
    The Apollo unified S-band system was developed to handle ranging, telemetry, and voice data using one carrier. Television is transmitted in another mode with the same system. Frequent references are made to the unified S-band system in this report because other systems must work in conjunction with it; however, no description is provided because the S-band system is discussed thoroughly in numerous other reports. The astronauts must coordinate their activities on the lunar surface, and communications are required between them as well as between them and Mission Control Center. A VHF system that has performed excellently in providing voice and telemetry information for lunar-surface use is described in this report. Interest in television has progressed from casual to intense as the Apollo Program has matured; technology has evolved to provide color presentations using the same RF system that was once limited to black-and-white transmissions. The cameras that were developed for both black-and-white and color transmissions are described. Future lunar-surface operations will require traverses too long to be accomplished easily on foot. A system that permits long-range communications from a motorized vehicle on the lunar surface is described. Finally, brief descriptions of several communications-related lunar-environment experiments that have been proposed for the Apollo Program are discussed.
  • A Projectile Telemetry System for In-Barrel Data

    Bentley, R. D.; Ruttle, C. J.; Sandia Corporation (International Foundation for Telemetering, 1970-10)
    Sandia Corporation is developing a projectile telemetry system and required ground support to monitor the performance of components mounted in a 155 mm projectile. The telemetry system is to provide the data link required to monitor component performance during and following launch from a 155 mm "long-tom" cannon. The projectile experiences a 16,500g setback acceleration of 15 msec duration coupled with an angular acceleration of 328,000 rad/sec². A P band FM/FM telemetry system has been developed to provide a data link while the projectile is in the barrel as well as out of the barrel. The technique has been successfully tested in a 155 mm projectile with a setback acceleration of 12,500g 20 millisec duration and in a 81 mm mortar round with a setback acceleration of 7,000g 7.5 millisecond duration. A parachute recovery system is used to obtain a "soft" recovery of the 155 mm projectile mounted components and telemetry system.
  • A Universal L-Band Telemeter for Use on Artillery Projectiles and Gun Launched Research Probes

    Richard, Victor W.; Hadowanetz, Wasco; Aberdeen Proving Ground; Picatinny Arsenal (International Foundation for Telemetering, 1970-10)
    A UHF (1520 MHz) telemetry system for use with artillery projectiles and gun launched research probes is described. The feasibility of a universal telemeter (UTM) is demonstrated which is based on the use of modular plug-in components available to meet a variety of instrumentation requirements, including ogive and rear mounting, thus, eliminating the need for the development of a special projectile telemetry unit for each application of in-flight projectile performance monitoring or gun probe experiment. The special, ruggedized components and techniques for pre-flight high acceleration testing are described. The components described include: broadband, omnidirectional antennas for ogive and base mounting in projectiles; a high gain, all polarization, fan beam receiving antenna; stabilized, high efficiency UHF transmitters; miniaturized voltage controlled oscillators; 8 and 16 channel commutators; button cell and g-activated reserve cell batteries; shock resistant, electrically compatible radome and encapsulating materials; modular assembly cases; and ogive and base mounted telemeter test projectiles. The physical and electrical characteristics of the components of the telemetry system are presented, along with laboratory and field performance data obtained from firing standard, 155 mm, spinning projectiles, including the reception of signals while the projectile is in the gun barrel.
  • VHF/UHF Antenna Calibration Using Radio Stars

    Taylor, Ralph E.; Stocklin, Frank J.; Goddard Space Flight Center (International Foundation for Telemetering, 1970-10)
    This paper describes a stellar calibration technique, using radio stars, that determines receiving system noise temperature, or antenna gain, at frequencies below 500 MHz. The overall system noise temperature is referenced to radio star flux densities known within several tenths of a decibel. An independent determination of antenna gain must be made before computing system noise temperature and several methods are suggested. The preferred method uses celestial and receiving system parameters to compute gain; whereas a less desirable method requires an accurately known output level from a standard signal generator. Field test data, obtained at 136 MHz and 400 MHz in the NASA space tracking and data acquisition network (STADAN), demonstrates that antenna gain and system noise temperature can be determined with an accuracy of 1 db. The radio stars Cassiopeia A and Cygnus A were used to calibrate 40-ft. diameter paraboloidal antennas, at 136 MHz and 400 MHz, and phase array antennas at 136 MHz. The radio star calibration technique, described herein, makes possible accurate station-to-station performance comparisons since a common farfield signal source is observed. This technique is also suitable for calibrating telemetry antennas operating in the IRIG 216-260 MHz frequency band.
  • Video Bandwidth, if Bandwidth and Peak Deviation in Notch Noise Testing

    Little, K. G.; Astro Communication Laboratory (International Foundation for Telemetering, 1970-10)
    This paper presents guidelines for conducting notch noise testing of telemetry transmitter-receiver systems. An understanding of the type of FM-FM modulation format which random white noise accurately simulates leads to certain convenient relations between spectral power density, video bandwidth, peak deviation and IF bandwidth. Notch noise measurements were made on video noise in a video limiter to determine the dynamic range required of a system which transmits random white noise faithfully. These measurements were of significant importance because they show that a great deal of excess IF bandwidth is required to transmit random noise spectra. Specifically, it was found that to achieve a 50 db notch noise measurement the system dynamic range may be as much as 10 times greater than the RMS value of the composite signals.
  • Noiseless Linear Feedback and Analog Data Tranmission

    Butman, S.; California Institute of Technology (International Foundation for Telemetering, 1970-10)
    It is well known that noiseless linear feedback achieves channel capacity for the additive Gaussian channel. It has also been shown that it can be used to achieve the rate-distortion bound on the mean squared error for an arbitrary Gaussian source sent over the infinite bandwidth white Gaussian channel. However, it is shown here that noiseless linear feedback by itself does not suffice when the channel is bandlimited. It is shown that, out of the more than countable variety of Gaussian sources that ordinarily exist, only a countable subset can be transmitted via the bandlimited noiseless feedback link at the theoretical efficiency predicted by Shannon's rate-distortion bound. Thus, some nonlinear operations are necessary in almost all cases even with feedback.
  • A Burst-Trapping Code for Feedback Communication Systems

    Weinstein, S. B.; Bell Telephone Laboratories, Inc. (International Foundation for Telemetering, 1970-10)
    Many data communication channels are perturbed by "bursts" of noise separated by long intervals of comparatively low noise level. The block code described in this paper, a modification of the forward-acting scheme of S. Y. Tong, retransmits information which has been damaged by a noise burst in place of the parity-check digits of future blocks. The responsibility for error detection and correction is divided between the receiver and (via the feedback channel) the transmitter in such a way as to maximize the defense against both noise bursts and the occasional random errors between bursts. There is a fixed delay for decoding, in contrast to the variable buffering delay of ordinary retransmission-request systems. As a result, storage requirements are minimized and there is a constant throughput rate. The feedback channel can incorporate as much delay and be as noisy as the forward channel without significantly impairing performance. Simulation results are provided to illustrate the performance.
  • On Linear Information-Feedback Schemes for White Gaussian Channels

    Fang, Russell J. F.; COMSAT Laboratories (International Foundation for Telemetering, 1970-10)
    For the transmission of a Gaussian information source over an additive white Gaussian-noise (AWGN) channel, several noiseless, linear-feedback schemes are shown to be the same in the sense that they not only achieve the rate-distortion bound on the minimum attainable mean-square error (MSE), but also possess identical system parameters. These equivalent schemes can be easily applied to solving the problem of optimally matching a colored Gaussian source with an AWGN channel. These equivalent schemes can further be employed to send messages from digital information sources over AWGN channels. It can be shown that any of these equivalent schemes as a decision-error probability which is the smallest among the class of all linear schemes. The condition of noiseless feedback can be relaxed to cover the more general noisy information-feedback case. A suboptimal scheme is proposed for transmitting data from a Gaussian source, whose output process has a power spectral density function which is uniform in some frequency range and zero elsewhere, over some AWGN channels to some destination. This suboptimal noisy feedback scheme can also be used to send data from a digital information source over an AWGN channel with better performance than can be achieved without noisy feedback.
  • Data Tranmission Over Channels with Noisy Feedback

    Tong, S. Y.; Bell Laboratories (International Foundation for Telemetering, 1970-10)
    A low-cost error control technique is proposed for bulk data transmission with noisy feedback link. The scheme is ideally suited for tape-to-tape bulk data transmission as well as the store-and-forward type of data transmission system. By partition data into superblocks, the technique can be used for any feedback retransmission system. We also show that the scheme can be modified to correct synchronization errors and that noise in the feedback link can be made extremely unlikely to contribute to decoding errors.
  • Feedback in Data Transmission

    Ebert, P. M.; Bell Telephone Laboratories (International Foundation for Telemetering, 1970-10)
    A survey of the possible gains to be realized by the use of various feedback techniques is given. Noiseless information feedback is considered in detail, and a transmission system for this latter case is given and analyzed. This system is shown to achieve a transmission rate very close to the largest rate possible.
  • Processing of NRZ PCM from 10 MB/Sec to 200 MB/Sec

    Gray, J. S.; Radiation Systems Division (International Foundation for Telemetering, 1970-10)
    The type of functions required to optimally process PCM plus noise are the same at low and high bit rates. At high bit rates there are severe constraints in synthesizing these functions due to limitations of present day devices and logic; and due to extrinsic effects of networks over broad baseband bandwidths. Techniques developed for signal conditioning, bit synchronization, group synchronization, and decommutation of NRZ PCM from 10 Mb/sec to 200 Mb/sec are presented. Multiple techniques were investigated in each area over the complete bit rate range of interest to ascertain performance versus complexity and cost effectiveness among different techniques at different bit rates.

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