• An Intelligent Digital Phase-Locked Loop with Integral Gain Control, Signal Quality and Lock Detection

      Melester, M. T.; Geoghegan, M. S.; Electrospace Systems, Inc. (International Foundation for Telemetering, 1988-10)
      An intelligent digital phase-locked loop with integral automatic gain control, signal quality and lock detection suitable for implementation using current digital signal processing devices is presented. By exploiting information derived from these functions operating in unison, it is possible to realize improved performance in an adverse environment where fading or abrupt signal outages are encountered. The system described consists of several functions operating under the direction of a stored program. The state diagram model of the program is discussed along with design considerations for the system elements. Various aspects of the system are simulated in the presence of noise and signal outage and compared to the performance of a conventional phase-locked loop.
    • International Telemetering Conference Proceedings, Volume 24 (1988)

      International Foundation for Telemetering, 1988-10
    • The IPTN's Airborne Data Relay System (ADReS): A System Concept and the Phase One System Configuration

      Soelaiman, Adi Dharma; Roesma, Fauzi Effendy; Indonesian Aircraft Industry Ltd. (International Foundation for Telemetering, 1988-10)
      By making use of NC212-200 commuter aircraft as an airborne container, the ADReS, a short for airborne data relay system, had been configured and tested in an experimental status during the year of 1987. A kind of test on EMC, EMI, RFI and telemetry data link were applied to the system. Prior to the IPTN's flight test program in the year of 1988 - 1992, the ADReS is designed not only to receive and to relay the data, but also planed to be able to process the data for quick data analysis purposes on board. This paper describes the ADReS system concept and its experimental status system - the Phase One system configuration.
    • Mass Memory Reliability Evaluation for On-Board Data Recording Applications

      Goodwin, Paul F.; Capots, Larry H.; Austin, Howard R.; Fairchild Space Company (International Foundation for Telemetering, 1988-10)
      When properly implemented, solid state memory technology can result in mass data storage products with very large mean time to failure (MTTF). Fairchild Space Company has developed a memory architecture for their Solid State Recorder (SSR), which optimizes solid state performance in terms of survival probability (> 10 years), speed (~ 140 Mbps), size, weight and power compared to market alternatives such as magnetic tape, magnetic disc, magnetic bubble and optical disc. The basis for the memory design was an in depth investigation of the survival probability of very large quantities of interconnected memory devices.
    • MMTS: Multi-Vehicle Metric & Telemetry System

      Aspnes, Richard K.; Yuma, Russell J.; Control Data Corporation (International Foundation for Telemetering, 1988-10)
      The Multi-Vehicle Metric & Telemetry System (MMTS) is a complete range system which performs real-time tracking, command destruct, and telemetry processing functions for support of range safety and the test and evaluation of airborne vehicles. As currently configured, the MMTS consists of five hardware and software subsystems with the capability to receive, process, and display tracking data from up to ten range sensors and telemetry data from two instrumented vehicles. During a range operation, the MMTS is employed to collect, process, and display tracking and telemetry data. The instrumentation sites designated for operational support acquire tracking and telemetered data and transmit these data to the MMTS. The raw data is then identified, formatted, time tagged, recorded, processed, and routed for display to mission control and telemetry display areas. Additionally, processed tracking data is transmitted back to instrumentation sites as an aid to acquire or maintain vehicle track. The mission control area consists of a control and status console, high resolution color graphics stations, and large screen displays. As the mission controller observes mission progress on the graphics stations operational decisions can be made and invoked by activation of the appropriate console controls. Visual alarms provided my MMTS will alert mission control personnel of hazardous conditions posed by any tracked vehicle. Manual action can then be taken to activate transmission of the MMTS vehicle destruct signal. The telemetry display area consists of ten fully-functional, PC compatible computers which are switchable to either of two telemetry front end processors. Each PC can be independently set up by telemetry analysts to display data of interest. A total of thirty data pages per PC can be defined and any defined data page can be activated during a mission. A unique feature of the MMTS is that telemetry data can be combined with tracking data for use by the range safety functions.
    • Modem Simulations for Possible Use in Space Station

      Horan, Stephen; New Mexico State University (International Foundation for Telemetering, 1988-10)
      Two candidate modem structures for use in the Space Station Multiple Access Communications System were simulated using a software simulation package to obtain symbol error rate curves. These systems represent an evolutionary QPSK through 8-PSK modulation format for the input data streams. It was found through the simulations that the use of phase-staggered QPSK modems would give lower expected implementation loss than a modem based upon the Polarity Costas Loop method. However, the latter would represent a simpler hardware investment to realize the modem structure for both QPSK and 8-PSK.
    • NASA-GSFC Research Developments Evolve into HRSO Satellite Concepts

      Hilliard, Lawrence M.; NASA-GSFC (International Foundation for Telemetering, 1988-10)
      Shaped omni and modular array antenna concepts are being baselined for use on operations with the NASA Space Network and the High Resolution Solar Observatory (HRSO) Satellite Free Flyer Concept. This mission requires 16 MBPS return links, 1 KBPS multiple access links, and a completely redundant set of gimballed antennas to support these links with 90% continuous coverage from TDRSS (Tracking and Data Relay Satellite System). This presentation will discuss in detail how the flexibility of these components enabled mission planners to tradeoff spacecraft options without sacrificing mission objectives.
    • The Need for Standardized Performance Characteristics for Digital Strip Chart Recorders

      Smith, Grant M.; Gaskill, Dave; Astro-Med, Inc. (International Foundation for Telemetering, 1988-10)
      Digital-based linear-array chart recorders are replacing conventional stylus recorders in telemetry data stations everywhere. They offer advantages in virtually all respects, and are becoming indispensable. But because of the completely different writing method and technology employed, it is difficult to make completely analogous performance comparisons between analog and digital chart recorders. This has led to some confusion when replacing aging stylus recorders is contemplated. Objectives: Establish a set of universal, standardized performance characteristics for digital chart recorders. Introduce appropriate terminology, allowing valid, repeatable comparison of old and new systems.
    • A New Microcomputer-Based Reel Servo System in the Instrumentation Magnetic Recorder

      Rui, Xiong; Yunxiang, Shao; Beijing Research Institute of Telemetry (International Foundation for Telemetering, 1988-10)
      This paper describes the design of a adaptive microcomputer-based reel servo system in the instrumentation magnetic recorder. When the reel parameters and load characteristics might vary during recording, the newly designed adaptive reel servo system is capable of compensating for these variations. The new reel servo system consists of a single-board microcomputer (QJ-80) and two D.C. motor actuators. A model reference adaptive control was chosen as the basis for adaptive reel controller design. The experiment results show that the new microcomputer-based reel servo system effectively eliminates the affect of the parameter variations. The performance of the whole transport system is improved therely.
    • A New Multi-Mission Data System for Space Flight Support Through the 1990's

      Gainsborough, A. J.; California Institute of Technology (International Foundation for Telemetering, 1988-10)
      Individual data systems for flight projects at JPL are in the process of being replaced by the single new Space Flight Operations Center (SFOC) that is designed to support multiple missions. The design provides a baseline system that supplies a common set of functions needed by every mission. Low cost adaptations of the baseline with any needed missionspecific additions are made for each mission. The SFOC is being developed in phases. The current phase provides baseline functions for downlink spacecraft telemetry processing with the necessary adaptations and additions for the downlink launch support in April 1989 of the Magellan mission to Venus. The SFOC will be completed in 1991, at which time the planned support includes both downlink and uplink processing for a projected six mission set.
    • A New S-Band FM Telemetry Transmitter

      Fengden, Lou; Beijing Research Institute of Telemetry (International Foundation for Telemetering, 1988-10)
      This paper describes the design, test and the analysis of the test results of a new type S-band FM telemetry transmitter. Compared with the modulator adopting conventional fundamental crystal direct modulation, the transmitter which adopts UHF fundamental crystal direct modulation has a comparatively better modulation characteristics and a higher center frequency stability. The test results show that the deviation sensitivity of the transmitter is up to 400KHz/Vrms, frequency response is DC~200 KHz, total harmonic distortion is 3% and the center frequency stability is ten to the minus fifth power within the range of - 30~+70°c. Because of the high operating frequency of the modulator, the complicacy of the frequency multiplier has been requced, design of circuitry simplified and harmonic and spurious outputs has been improved to a great extent.
    • Off-Loading the Host Computer Through Flexible DMA Interface

      Nicolo, Stephen J.; Aydin Monitor Systems (International Foundation for Telemetering, 1988-10)
      As data rates and system throughput requirements continue to increase, more and more attention must be given to ways of off-loading the host computer by shifting tasks to the front-end preprocessing subsystem. In addition to some of the more common tasks like data compression and EU conversion already performed in the front end, there is the time consuming task of organizing telemetry data. Once relieved from this secondary task the host can solely attend to its primary task of application processing. This paper describes an intelligent DMA interface (CPI007) which permits the automatic building of various types of array buffers in the host computer. This flexible high-speed device uses an EPROM based, bit slice microengine utilizing parameters stored in its operational store RAM during setup to build the array buffers. The interface is implemented on a single module in the front-end preprocessing subsystem and was developed for those mainframe computers that can be configured to accept address/data inputs for DMA to system memory (e.g. Gould Sel, DEC). With this type of architecture, algorithms may easily be written to accommodate a wide variety of data organization and transfer requirements. Along with the technical description of this device, actual data array buffering problems and solutions will also be addressed in this paper.
    • Onboard 1553 MUX Bus Recording Techniques

      Kirkpatrick, Charles R.; McDonnell Douglas Helicopter Company (International Foundation for Telemetering, 1988-10)
      This paper presents a general overview concerning McDonnell Douglas Helicopter Company's experience with the recording of Mil-Std-1553A/B MUX Bus traffic. There are several interesting aspects to this general overview. Included in this paper is a historical development review, a chronological development outline, general methodology involved, past and present application details, and speculation about future application possibilities. The historical background of the Company's 1553 MUX Bus recording efforts are traced - from our earliest involvement up to our current status. Several significant developments have led up to, and contributed to, the present level of experience with 1553 MUX Bus recording technology. A chronological list of important related events is also presented to complement this historical review (See Appendix A). Examples of McDonnell Douglas' applications of 1553 MUX bus recording are highlighted. Several examples are discussed from different related projects. A general overview is presented with regard to methods used by the Company to record 1553 MUX bus traffic. Several projects undertaken have involved new hardware/software development as a result of 1553 MUX bus recording efforts. Mention is also made of the Programmable MUX Bus Monitor - one of the most recent applications of this technology by McDonnell Douglas Helicopter Company. Rounding out this paper is some speculation about the future use considerations for this technology. The Company's experience with 1553 MUX bus recording was initially developed as a result of association with the Higher Harmonic Control aircraft and the AH-64 Apache Helicopter programs. However, once some of the basic techniques were established, and the technology was refined and improved, expansion into other unrelated or indirectly related (to the Apache) project types occurred.
    • Parallel Bus Implementations in Satellite Communications Systems

      Yun, Paul M.; E-Systems (International Foundation for Telemetering, 1988-10)
      As the volume of linkages in the satellite communications systems increases, the parallel bus between the various processors of the satellite becomes a bottle neck to transfer the commands and data. The remedies to this problem are trivial in the ground stations; however, this problem imposes severe restrictions in parallel bus implementation of the satellite communications systems. The most severe restriction is the minimization of wire connections in the physical layer to minimize the weight, size and power consumption, and also to maximize the reliability. Another restriction is the flexibility in the link layer to adapt the different characteristics of the command and data messages. In this paper, the implementation to overcome the imposed restrictions in both physical and link layer of the parallel bus will be discussed.
    • A PCM Telemetry System Using Programmable Logic Devices

      Stewart, Michael T.; Sandia National Laboratories (International Foundation for Telemetering, 1988-10)
      This paper discusses a PCM telemetry system consisting of programmable logic devices (PLDs) and off-the-shelf analog ICs. A finite state machine (FSM) serves as the system controller. All digital logic, including the FSM, is implemented using PLDs. This approach has two important features. First, the use of an FSM offers a significant speed advantage over microprocessor-controlled systems. Second, the use of PLDs offers a high degree of design flexibility while obtaining a low-power, low-volume system.
    • Performance of Contention Bus Networks with Baseband Captures

      Ward, Dale; Northwestern University (International Foundation for Telemetering, 1988-10)
      Power capture is the characteristic of one signal overpowering the others in contention for a receiver. In a multiple access network which employs contention protocol, occurrence of capture helps a receiver distinguish correctly one signal given that multiple transmissions overlap over the common channel. It has been reported in the literature that performance of radio networks could substantially be higher in the presence of captures than it is without captures. The captures involved in radio networks are primarily FM captures. In this paper, we examine the effect of baseband captures on performance of contention bus networks. In particular, we show that signal attenuations on a cable channel could produce a significant chance of captures and hence greatly lift the throughput.
    • Practical Decom List Switching

      Devlin, Steve; Aydin Monitor Systems (International Foundation for Telemetering, 1988-10)
      With more complex vehicle designs, the frequency and number of measurements contained in telemetry data streams has dramatically increased. One way of improving the use of bandwidth is to change the sample rate, quantity, or type of measurements dynamically. A telemetry front end must be programmable to handle different formats. In a front end that decommutates and routes measurements, a decom list is a control program, which defines the location, size, orientation, and identity of the measurements. To deal with dynamic format changes, a telemetry front end must be able to switch between decom lists. A practical approach to decom list switching must address the needs of error avoidance, packet switching, and the location of switching keys in any portion of the format. Switching between formats should not be restricted to a preprogrammed sequence, but should allow multiple destinations from a particular decom list. A practical and flexible implementation of decom list switching is detailed along with an explanation of how this implementation solves a variety of decommutation problems.
    • Problems and Methodology of High Data Rate Telemetry

      Baghdady, Elie J.; EJB Research Associates (International Foundation for Telemetering, 1988-10)
      The ultimate limitations on data rate are set by factors categorized in this paper into transmission medium problems, equipment problems and signal characteristics in the generalized spectral dimensions of time, frequency and open space. The limiting factors and corresponding relieving approaches are briefly brought out in this essentially topical summary paper. This paper is primarily a topical guide for a much more detailed multiple-hour tutorial lecture.
    • A Programming Parallel Real-Time Process Data Flow Telemetry System

      Da-qing, Huang; Nanjing Aeronautical Institute (International Foundation for Telemetering, 1988-10)
      In this paper, a programming parallel real-time process data flow telemetry system is presented. What we developed recently is a advanced telemetry system which can process multi-data-flow of multi-target for mulit-user at the same time. It can be used in RPV, missile and others. Its main characteristics are as follows: Input radio frequency is S wave band (multi-dot frequencies). In telemetry front-end, the chip microprocessor is used to make demodulation and decode. Telemetry preprocessor consists of parallel distributed chip microprocessor mould plates (bus link). There are menu shope man-computer dialogue, figure display, intelligence display and intelligence self-diagnosis in this system. Now, we have developed data compress mould plate, floating-point arithmetic mould plate, derive calculation mould plate and signal process mould plate etc. The main computer is VAX-II.
    • A Quantized Euclidean Soft-Decision Maximum Likelihood Sequence Decoder: A Concept for Spectrally Efficient TM Systems

      Carden, Frank; New Mexico State University (International Foundation for Telemetering, 1988-10)
      Trellis-Coded Modulation, TCM, combines the processes of modulation and encoding to achieve an overall coding gain that is usually greater than that achieved by performing the operations independently. This paper is concerned with utilizing TCM and 8-PSK to achieve a spectrally efficient modulation scheme with a constant envelope. Since TCM involves Euclidean distance as a metric, the concept of a quantized decoder is developed to decrease the decoding time.