• A Digital Instrumentation System for Automotive Impact Tests

      Hu, A. S.; Bean, S. P.; Maure, J. J.; New Mexico State University (International Foundation for Telemetering, 1976-09)
      Automotive impact tests require the transmission of large amount of measurement data through drag cables. The traditional practice of using FM technique is tedious and expensive. An on-board PCM system which accepts 112 analog inputs and 91 bi-level inputs has been used successfully at the Daisy Impact Sled Test Track located at the Holloman AFB. This system utilizes a two-conductor pair drag cable. It can also be telemetered by pulse modulating a radio frequency carrier.
    • Distribution of Intelligence and Input/Output in Data Acquisition Systems

      Rose, Charles W.; Schoeffler, James D.; Case Western Reserve University; Cleveland State University (International Foundation for Telemetering, 1976-09)
      Low cost, high performance microprocessors are being used in several distributed intelligence architecture to replace conventional data acquisition systems. Each distributed topology has certain attributes which affect its suitably for data acquisition applications: cost and position modularity, behavior in the presence of a fault, logical complexity, and bottlenecking. The software organization of these systems is impacted by the distribution of intelligence and input/output, particularly in the areas of task communication, error recovery, data base management, and operating systems structure. A ring structure has been developed for data acquisition and control, which uses distributed microprocessor intelligence and modified serial CAMAC protocol. A general purpose instrument and communications control module based upon INTEL 3000 microprocessors has been built.
    • Remote Controlled Telemetry Receiver Considerations

      Knowles, Robert C.; Microdyne Corporation (International Foundation for Telemetering, 1976-09)
      As the complexity of telemetry systems increases, the desirability of using remote controlled receivers in these systems to reduce human error, setup time, and premission calibration time increases. The specification of such receivers needs to be done carefully to stay within economic and space limitations. A general discussion of possible system objectives is given in which basic decision questions are raised on the degree of remote control required. A tabulation of receiver functions and controls is given followed by detailed discussion of these various parameters in terms of feasibility, problem areas, space requirements and cost where it represents a major impact. The computer-receiver interface is discussed in terms of how this choice will affect cost and system compatibility with other types of equipment. These discussions should provide some insight in the tradeoffs required in specifying a remotely controlled telemetry receiver.
    • Microprocessors for Satellite Telemetry - A Universal Approach

      Campoli, Peter H.; Brede, S. K.; Spacetac, Inc.; Analytyx Electronic Systems, Inc. (International Foundation for Telemetering, 1976-09)
      A system has been developed which can be flexibly tailored to meet most telemetry requirements. The concept results in higher reliability, greater modularity, and lower cost than classical approaches. It also offers more system capability. The development was realized by adaptation of the telemetry requirements to a computer system architecture. Such an adaptation is made possible by the use of a microprocessor as a device controller. The concept has been successfully applied to a specific telemetry requirement for use on a satellite. The results have far-reaching implications on the future of spacecraft electronics. Reductions in overall system hardware are possible while increasing the functional capability.
    • Production Counting Using a Computer Network

      Knoop, Donald E.; Loessel, Mark C.; Whirlpool Corp. (International Foundation for Telemetering, 1976-09)
      The advent of microprocessors has made possible the development of low cost intelligent terminals for industrial applications. Several of these "smart" terminals can be connected to a communications network which is controlled by a it "master" computer. Such a computer network has been developed at Whirlpool Research for use in production counting for inventory control purposes. This paper discusses the design, development, installation and debugging of the production counting system. The advantages and limitations of this type of computer network are discussed in the context of the industrial environment.
    • Distributed Control ... Relevance & Ramification for Utility and Process Applications

      Keyes, M. A.; Bailey Meter Company (International Foundation for Telemetering, 1976-09)
      Distributed digital control systems have appeared structurally desirable for many years. The concepts of hierarchial control and distributed risk were advanced as necessary structural considerations in the control of large scale systems almost coincidentally with the advent of modern electronic instrumentation and digital process control computers. The logarithmic growth patterns of semiconductor technology over the last two decades and the availability of microprocessors and other manifestations of large scale integrated circuitry have finally converted the distributed digital control system from a structurally desirable nicety to an economic inevitability. This paper examines the relevance of distributed digital control systems in the rigorous industrial environment of energy, utility, and process control applications. Design considerations leading to minimization of total installed system costs while retaining the necessary system flexibility to allow user reconfiguration to meet changing process or product needs are delineated. The twin problems of reliability and maintainability are examined in the context of allowable structural degradation concepts which must be inherent in the design of any distributed system.
    • Considerations for Distributed Industrial Control Systems

      Griem, P. D., Jr.; Bernard, J. W.; Foxboro Company (International Foundation for Telemetering, 1976-09)
      For a variety of reasons, industrial plant control systems have been increasingly complex and expensive. Economic and reliability considerations have initiated a trend toward distributing control system functions among communicating components, utilizing the new microprocessor and communication technologies. Any new technology brings new capabilities, but also new engineering design considerations and trade-offs. This paper attempts to outline some of the important system design issues.
    • Trends in the Control and Monitoring of Future European Satellites

      Fiorica, F.; European Space Agency (International Foundation for Telemetering, 1976-09)
      Current and future programmes of the European Space Agency (ESA) consist of relatively few missions but widely diversified in nature. The control and monitoring operations can be performed using either a specialized common band or the different payload frequency bands as assigned to each mission. The trade-off is discussed in the paper and considerations for the choice of the most suitable band presented. Some features of the preferred approach both for the ground and the space segments are illustrated as well.
    • A Wideband-PCM Recorder for the Space Shuttle Orbiter

      Petit, R. D.; Odetics, Inc. (International Foundation for Telemetering, 1976-09)
      A wideband-PCM recorder has been developed for use in the avionics instrumentation subsystem of the Space Shuttle Orbiter. In direct contrast with the single function Apollo and Skylab recorders, this recorder is designed to meet a variety of present and future applications. The Shuttle recorder uses the tape transport and motor drive design from the NASA-Goddard Space Flight Center (NASA-GSFC) Standard Tape Recorder. This design was directed by the NASA-GSFC with funding provided by the Low Cost Systems Office at NASA Headquarters. Recording is accomplished on up to 14 data tracks with analog or digital data inputs. FM multiplexed analog frequencies of up to 2 MHz and digital rates of 1 Mb/s are accommodated at a tape speed of 120 inches/second. Recording time in the analog mode varies between 4 minutes for 2 MHz data to 80 minutes for 100 KHz data. The total digital data storage is 3.44 x 10⁹ bits with recording times from 1 hour for 1 Mb/s data to 19 hours for 50 Kb/s data in the serial track switching mode. A versatile command decoder and control interface are used for eight primary modes of operation. The recorder responds to over 7,000 commands which are combinations of the eight modes, four tape speeds, four delay times, four run periods and track selection. The commands are formatted as 16 bit words by onboard computers or simple, single switch panel commands initiated by the astronauts. The Shuttle recorder uses a hermetically sealed transport unit, occupies approximately 2,000 cubic inches and weighs 41 pounds. Operation through launch and re-entry vibration environments is accomplished by use of isolators which mount the transport unit to the electronics unit. Tape life is in excess of 20,000 passes without maintenance.
    • The Implementation of an On-Board Data Handling System by a Programmable Modular Concept

      Frölich, Horst; Dornier System GMBH (International Foundation for Telemetering, 1976-09)
      The implementation of On-Board Data Handling Systems by individually tailored electronics leads to high development costs and risk. In order to overcome these shortcomings for future applications of on-board tasks, a complete modular concept has been developed for control, data acquisition, data reduction and telemetry encoding in onboard aerospace vehicles. This highly flexible concept consisting of a large spectrum of real time peripherals and different central processing units has meanwhile proven its high flexibility in a wide spectrum of applications. The system is freely programmable and supported by extensive software for program development and testing. The application software can be developed on host computers of different types. The paper gives a description of the system. By the example of an application in an aerospace telemetry and control system the advantage of using this modular approach is demonstrated.
    • The Joint AEROSAT Evaluation Programme

      Geigner, Oskar L.; AEROSAT Coordination Office (International Foundation for Telemetering, 1976-09)
      The Joint AEROSAT Evaluation Programme has been established by several European States, the United States and Canada in response to recommendations of the 7th Air Navigation Conference of the International Civil Aviation Organisation (IACO) held in April 1972 in Montreal. This group of 11 States has agreed to conduct a single international progranne of experimentation and evaluation in order to facilitate the application of satellite technology to international civil aviation needs. The institutional arrangement devised for such a joint international programme is defined in a Memorandum of Understanding, which was executed in 1974 between the Federal Aviation Administration (FAA), the European Space Agency (ESA), representing the European States, and Canada, with provisions for participation by other countries in the future. An AEROSAT Council was established to oversee this international cooperative effort. The authority and responsibility for the day-to-day implementation of the Coordinated Programme rests with the AEROSAT Coordination Office (ACO), which was established in June 1975.
    • ATS-6 European L-Band Aeronautical Experiments

      Brown, D. L.; Guérin, Y.; Melchior, G.; Absolonne, F.; European Space Tecnhology Centre (International Foundation for Telemetering, 1976-09)
      This paper describes the European experiments and test results obtained in L-band (1550-1650 MHz),using the NASA ATS-6 satellite, to conduct communication and navigation tests over the North Atlantic thus assisting in the definition of modulation techniques to be used with an Aeronautical Satellite System, AEROSAT. The experiments conducted by ESA and some of its member states covered voice, data transmission and ranging measurements. The tests were performed on board a Comet IV aircraft equipped with a slot dipole array antenna, especially designed to operate within the coverage required in the AEROSAT MOU (Memorandum of Understanding for the AEROSAT programme signed by Europe (ESA), the USA (FAA) and Canada (DoT) in August 1974. The voice tests compared DELTA-PSK with adaptive NBFM using test tapes consisting of logatoms, SCIM sequences, and PB word lists. An investigation of multipath noise effects on the PSK data transmission system was carried out and led to the general conclusion that this problem is a serious one for coherent demodulators. The DECPSK system tested exhibited a strong tendency towards a Rayleigh channel BER situation at low antenna signal to multipath interference ratios. The ranging results show the feasibility of achieving standard deviations of range of around 500-600 m for the PLACE tone system with its rather short integration time of 120 ms, and 100 m for the DIOSCURES pseudo random coded system operated on a CW basis.
    • An Adaptive Intrusion Data System

      Johnson, Charles S.; Sandia Laboratories (International Foundation for Telemetering, 1976-09)
      An Adaptive Intrusion Data System (AIDS) was developed to collect data from intrusion alarm sensors as part of an evaluation system to improve sensor performance. AIDS is a unique digital data compression, storage, and formatting system. It also incorporates capability for video selection and recording for assessment of the sensors monitored by the system. The system is software reprogrammable to numerous configurations that may be utilized for the collection of environmental, bi-level, analog and video data. The output of the system is digital tapes formatted for direct data reduction on a CDC 6400 computer, and video tapes containing timed tagged information that can be correlated with the digital data.
    • Command and Control of a Large, Unmanned, Undersea Vehicle

      Linders, Thomas E.; Lockheed Missiles & Space Co., Inc. (International Foundation for Telemetering, 1976-09)
      A system incorporating commercial modems and two twisted-pair shielded wires makes it possible to control/monitor a large unmanned undersea vehicle from a surface vessel. This paper summarizes the design, explains the rationale for it, and describes some of the problems encountered and their solution.
    • Simulation of the Effects of Hard Limiting on Image Quality of Synthetic Aperature Radar

      Lipes, Richard G.; Butman, Stanley A.; Caltech’s Jet Propulsion Laboratory (International Foundation for Telemetering, 1976-09)
      Starting with a magnetic tape of a scene viewed by the ERTS (Landsat) satellite, we simulated the radar return of reflectors whose average intensity matched that of the picture elements in the scene. The returns were processed in three ways: normally or with no quantization, with a procedure simulating IF (intermediate frequency) hard limiting, and with a procedure simulating video (baseband) hard limiting. For each type of processing we developed an image for a one, two, and four-look system. We found that IF limiting is slightly better than video limiting, while both can be reasonable trade-offs of image quality for reduced data rates when the number of looks is four or less. These conclusions are supported by photographs representing the different processing techniques.
    • Supervisory Control and Telemetry Using Emulation-Type Microcomputer

      Yanaka, Masao; Takahashi, Masahiro; Kobayashi, Kazuhiko; Hasegawa, Syuzi; Hitachi Ltd. (International Foundation for Telemetering, 1976-09)
      An advanced Supervisory Control and Telemetry system has been developed to meet the diversified requirements from the widening range of application fields such as utility industries, highways and railways. The transmission procedure employed is Cyclic Digital Transmission (CDT)a procedure most widely adopted in Japan, especially in the electric power control field. The master station possesses the capability of accomodating equivalently as many as 32 remote stations linked over 1200 b/s carrier channels on a realtime basis. This processing power has been achieved by the use of an emulation-type microcomputer, into which a specially developed set of microinstructions are incorporated as part of firmware to get the optimal tradeoff between hardware and software.
    • Pulse Code Modulation Recording for Telemetry Applications

      Waggener, William N.; EMR-Telemetry (International Foundation for Telemetering, 1976-09)
      The problems of signal design and detection and multitrack synchronization are examined for pulse code modulation high-density digital recording. Theoretical bit error probability results are compared with experimental data taken for bandlimited conditions typical of tape recorders. The problem of synchronizing multiple-track data is considered and the maximum likelihood synchronizer is obtained. Variations on the maximum likelihood synchronizer are considered.
    • A Sampling Window Test Method for Evaluation of Phase Encoded Recorder Systems

      Lerma, J. P.; Lindquist, C. A.; Odetics, Inc. (International Foundation for Telemetering, 1976-09)
      Self-clocking, digital phase encoded data formats have gained popular acceptance in the field of high density digital magnetic recording. At high transition densities, random noise processes can play a prominent role in determining system performance and reliability. The eye pattern technique of assessing the relative merit of a signal with respect to noise is severely limited at high transition densities. The stringent requirements associated with high density recording and the limitations of eye pattern analysis have stimulated the development of a digitally implemented sampling window analyzer which permits the direct evaluation of the statistical properties of a digital phase encoded reproduce waveform. The analyzer observes data transitions through two time sampling windows for the purpose of estimating pattern independent conditional probability. The statistical parameters of the conditional probability obtained can be used to detect latent sources of noise and to define optimum record zone parameters.
    • High-Density Digital Data Recording/ Reproducing System

      Leighou, Robert O.; Martin Marietta Corporation (International Foundation for Telemetering, 1976-09)
      Problems associated with reliably recording and reproducing digital data at densities of 10 to 30 kilobits per inch and the solutions to these problems are discussed. The three problems are skew, dc offset, and tape imperfections. The solutions are to use a 14-track, wideband II tape recorder; record NRZ-L; use a 24-bit sync word, 504-bit frame length, and odd parity in every 8-bit byte; and to employ circuit design techniques that minimize the effects of the remaining dc offset and tape imperfections.
    • Magnetic Tape Synchronizer/Controller

      Schoeck, K. O.; Martin, S. W.; Vandenberg Air Force Base; Datatape (International Foundation for Telemetering, 1976-09)
      A method has been developed to time synchronize multiple wideband magnetic tape recorder/reproducers to allow realtime data merging of tapes from various tracking stations. The system operates using either IRIG A and/or IRIG B time codes, and maintains synchronization within 10 microseconds using IRIG A and 50 microseconds using IRIG B.