• 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.
    • Reaction Torque Minimization Techniques for Articulated Payloads

      Kral, Kevin; Aleman, Robert M.; Honeywell-Sperry Space Systems; Goddard Space Flight Center (International Foundation for Telemetering, 1988-10)
      Articulated payloads on spacecraft, such as antenna telemetry systems and robotic elements, impart reaction torques back into the vehicle which can significantly affect the performance of other payloads. These disturbances can degrade the quality of the data obtained by other on board experiments and systems. This paper discusses ways to minimize the reaction torques of articulated payloads through command shaping algorithms and unique control implementations. The effects of reaction torques encountered on the LANDSAT satellite are presented and compared with simulated and measured data of prototype systems employing these improvements.
    • Realtime Telemetry Processing System (RTPS) III: A Preview of Software Development in the 1990s

      Hill, Jerry L.; CSC Network Systems Division (International Foundation for Telemetering, 1988-10)
      Software development is becoming less an art form and more an engineering discipline. Methods of software development which leave as little as possible to chance are constantly being sought and documented. However, the gap between what is written and what is actually applied is usually quite wide. The only way this gap can be narrowed is through practical application of these very detailed and complex methods. Since it is unlikely that the complexity of these methods will be reduced, automation must be employed wherever possible in the software development process. This paper addresses the successful development of software for the Navy's Realtime Telemetry Processing System III (RTPS III) using practical application of existing methodology in conjunction with a Computer Aided Software Engineering (CASE) tool. Based on this experience, the conclusion presents implications affecting software development the 1990s.
    • Receiver/Combiner for Shipboard Telemetry Applications

      Baker, Thomas G.; Lennox, William M.; Naval Surface Warfare Center; Microdyne Corporation (International Foundation for Telemetering, 1988-10)
      Improvements in the performance and electronic sophistication of Navy missiles require concurrent improvements in telemetry reception. The Microdyne 2800 Receiver/Combiner, developed for the Naval Surface Warfare Center (NSWC), provides an improved shipboard receiving capability to meet this requirement. The Microdyne 2800, or "2800", is a dual channel diversity combining telemetry receiver, which, though designed to meet the unique Navy shipboard environment, provides a capability previously available only with large shore based receiving systems.
    • Reliable Solid State Data Storage Device for Spacecraft T&C Subsystems

      Capots, L.; Chitty, R.; Ameti, A.; Mitchell, W.; Fairchild Space Company (International Foundation for Telemetering, 1988-10)
      Fairchild Space Company, a division of Fairchild Industries, has developed an advanced data recorder based exclusively on the use of Solid State circuitry for the recorder memory. This paper describes the recorder, its development, the engineering considerations for long-term mission life, methods for minimizing size, weight and power, and the flexibility of the recorder to accommodate a number of different mission requirements. Unlike the more traditional mass storage devices for spacecraft, which use rotating memory, the Solid State Recorder (SSR) uses a true random access memory. This feature has resulted in a multi-mode storage device, which can greatly reduce the complexity of spacecraft data systems. Today's spacecraft have large numbers of sensors and high rate instruments which are making the data flow problem much more difficult to handle. Bottle necks also referred to as "data fusion" have become a serious problem for systems engineers, for which the SSR may represent an effective solution. The paper concludes with a discussion of some system applications which illustrate the broad range of possible SSR applications, and the development status.
    • Research and Recommendation of Optimum Group Synchronization Codes for N = 7 -- 32

      Zhongkui, Lei; Qiucheng, Xie; Jie, Cao; Nanjing Aeronautical Institute (International Foundation for Telemetering, 1988-10)
      In this paper, based on a series of research achievements [2,3,4,5,6], are examined the "The Optimum Frame Synchronization Codes" provided by J. L. Maury Jr. and F. J. Styles for IRIG Telemetry Standards USA, and furthermore, recommended a set of Optimum Group Synchronization Codes for China Telemetry Standards.
    • RF Hybrid Linear Amplifier Using Diamond Heat Sink

      Karabudak, Nafiz; Aydin Vector Division (International Foundation for Telemetering, 1988-10)
      This paper will address the applications and methods used for a high power output RF linear small signal amplifier using diamond heat sink. Comparison and the benefits of using diamond heat spreaders will be reviewed. Agrowing number of researchers, engineers and scientists are looking into the applications of diamond's unique properties such as physical, electrical and optical.
    • Ruggedized Television Compression Equipment for Test Range Systems

      Gattis, Sherri L.; Naval Weapons Center (International Foundation for Telemetering, 1988-10)
      The Wideband Data Protection Program was necessitated from the need to develop digitized, compressed video to enable encryption.
    • S-Band Phased Array Antenna for the E-9A

      Cooke, William P.; Burdette, Lawrence; Zoledziowski, Severyn; Hatcher, Glenn; Georgia Institute of Technology; LTVMEG; Eglin Air Force Base (International Foundation for Telemetering, 1988-10)
      This paper describes the requirement, design and test results for the Airborne Phased Telemetry Array for the E-9A Airborne Platform.
    • The Searching Method of Optimum Frame Synchronization Codes Based on the Synthetic Optimum Criterior

      Jie, Cao; Qiu-Cheng, Xie; Nanjing Aeronautical Institute (International Foundation for Telemetering, 1988-10)
      This paper gives a new searching criterior of optimum or suboptimum frame sync codes that escapes from unnecessary calculation and presents a searching method. It has a great improvement on existing methods (exhaustion technique, and so on) and the computing time is decreased by 1~2 order of magnitudes. Finally, the optimum frame sync codes with the length n from 7 to 32 are given.
    • Sensing of Irregularities on Fast Moving Surfaces by Microwaves and Millimeterwaves

      Ishii, T. Koryu; Marquette University (International Foundation for Telemetering, 1988-10)
      Fine cracks and irregularities on a fast moving conducting surface were detected by the use of microwave and millimeter wave radio responder techniques. The interrogation angle was restricted to an oblique incidence angle less than ±0.5 degree from the surface. The fast moving conducting surface was surrounded by both fast moving and stationary reflective conducting structures. Experimental methods and results from a fine crack 0.1 mm wide, 0.9 mm deep, and 25 mm long on a conducting surface travelling with a speed of 20.23 m/s and measured at 10.525 GH(z) and 73 GH(z) are presented. The reflection-type microwave radio responder consisted of a 10.525 GH(z) 50 mW Gunn diode cw transmitter, a circulator, and a horn antenna used as the interrogator. The receiver in the same responder consisted of the same horn antenna, the circulator and detector diode. The detector diode output was observed with a Norland 3106R digital memory oscilloscope. A reflex kylstron VA 250 was used as the transmitter signal source for the millimeter wave responder. There was a distinct difference between the responder output patterns with uncracked and cracked surfaces. It is therefore possible to use this type of responder for hair-line crack detection of fast moving conducting surfaces. It was also found that this type of radio responder can detect the surface irregularity even before the hairline crack actually occurs.
    • Several Problems in Chinese Development of Telemetry Technology

      Chang-jie, Shi; Shang-ren, Li; Ministry of Aeronautics and Astronautics; Beijing Research Institute of Telemetry (International Foundation for Telemetering, 1988-10)
      1. What is the reason for the telemetry ground station using computer technology widely and deeply? 2. How to solve the problem of measuring fast varing signal? 3. Bit rate of telemetry ground station.
    • Simple Digital Encoder for NTSC Composite Video

      Milles, George T.; Naval Weapons Center (International Foundation for Telemetering, 1988-10)
      The need exists to encode NTSC composite video into a serial digital bit stream for encryption prior to transmission. Further, this need exists in places where power and volume are at a premium. This paper describes a simple solution using the Continuously Variable Slope Delta Modulation technique of encoding all lines and fields in real time and is usable with clock rates from 5 to 25 MHz. The circuits presented use only a 5-volt power supply and two active devices: a comparator and either a dual flip-flop or serial shift register.
    • Software Control of a High Speed, Modular Signal Conditioner and PCM Encoder System

      Trover, William F.; Teledyne Controls (International Foundation for Telemetering, 1988-10)
      The increasing channel capacity and complexity of flight test data acquisition systems have made the problems of physical distribution of the system throughout the test aircraft and determining the system configuration a very time consuming and costly portion of the flight test process. These problems are complicated because the new aircraft, irrespective of size, have more complex systems and less space is available to install the classical data acquisition and recording system. The solution to the installation problem is to have a highly modular system that can be configured as either a distributed system with remote multiplexing and a PCM Central Controller, or with the same multiplexed hardware as a stand-alone or master/slave system where the functional power and complexity afforded by the PCM Central Controller are not required. The solution to the configuration control problem is to have a 'hands-off' data acquisition system with all variables of the signal conditioning and PCM encoding functions under software control. In one concept, this includes functions such as instrumentation amplifier gains and offsets, presample filter knee selection, a common gain programmable amplifier with programmable offsets, and randomly addressable multiplexers with a PCM Central Controller that can store multiple data cycle maps. With all of the variable functions of the system under software control, system configuration can be determined automatically during pre- and post-flight test from a portable ground test set that produces a hardcopy printout of the system configuration. This system concept is being augmented by increasing sampling rate capability up to 500k sps for processing vibration/acoustic data. Fiber optical communications are available between the PCM Central Controller and the remote signal conditioners and multiplexers to provide immunity from extremely high common mode plateaus between subsystem elements located in different parts of a composite materials airframe. This next generation data system is being developed for general purpose flight and ground test applications.