• RECENT ADVANCES IN LOSSLESS CODING TECHNIQUES

      Yovanof, Gregory S.; Eastman Kodak Company (International Foundation for Telemetering, 1991-11)
      Lossless data compression systems allow an exact replica of the original data to be reproduced at the receiver. Lossless compression has found a wide range of applications in such diverse fields as: compression of computer data, still images (e.g., medical or graphical images) and video (usually, in the form of entropy coding of the output of intra/inter-frame lossy schemes). It has been studied for over forty years and new compression algorithms are still continuously developed. This paper is a survey of current lossless techniques with results quoted for both sequential data files and still images.
    • PULSE CODE MODULATION DATA COMPRESSION FOR AUTOMATED TEST EQUIPMENT

      Navickas, T. A.; Jones, S. G.; Allied-Signal Inc. (International Foundation for Telemetering, 1991-11)
      Development of automated test equipment for an advanced telemetry system requires continuous monitoring of PCM data while exercising telemetry inputs. This requirements leads to a large amount of data that needs to be stored and later analyzed. For example, a data stream of 4 Mbits/s and a test time of thirty minutes would yield 900 Mbytes of raw data. With this raw data, information needs to be stored to correlate the raw data to the test stimulus. This leads to a total of 1.8 Gb of data to be stored and analyzed. There is no method to analyze this amount of data in a reasonable time. A data compression method is needed to reduce the amount of data collected to a reasonable amount. The solution to the problem was data reduction. Data reduction was accomplished by real time limit checking, time stamping, and smart software. Limit checking was accomplished by an eight state finite state machine and four compression algorithms. Time stamping was needed to correlate stimulus to the appropriate output for data reconstruction. The software was written in the C programming language with a DOS extender used to allow it to run in extended mode. A 94 - 98% compression in the amount of data gathered was accomplished using this method.
    • Transmission of a PCM Telemetry Subcarrier with a Baseband TV Signal

      Rose, Robert P.; Rieger, James L.; Naval Weapons Center (International Foundation for Telemetering, 1991-11)
      An FM television system using a baseband color TV signal with a 100 kB/s PCM data FM subcarrier is described. Techniques used are based more like those for satellite transmission of TV images than those used for telemetry or broadcast TV. Discussion of optimization of transmission bandwidth, deviation, and subcarrier injection levels are discussed, along with the philosopy and application of such designs in instrumentation systems.
    • PROBABILITY OF FALSE POLYNOMIAL DIVISION SYNCHRONIZATION USING SHORTENED CYCLIC CODES

      Schauer, Anna Lynn; Ingels, Frank M.; Mississippi State University; Sandia National Laboratories (International Foundation for Telemetering, 1991-11)
      Shortened cyclic codes are not cyclic, but many cyclic shifts of various code words are still part of the shortened code set. This paper addresses the probability of false synchronization obtained through polynomial division of a serial shortened cyclic code stream in a “sliding” window correlator.
    • DESIGN OF A DATA ACQUISITION SYSTEM BASED ON THE DECOMMUTATION OF AN EMBEDDED ASYNCHRONOUS DATA STREAM WITHOUT PRIMARY AND SECONDARY FRAME SYNCHRONIZATION

      Kvasnak, Michael A.; Koonmen, James P.; Grajeda, Vivian L.; Space Technology Directorate (International Foundation for Telemetering, 1991-11)
      The use of embedded asynchronous data streams is becoming a popular means of expanding existing telemetry systems and acquiring subsystem data. In such systems, synchronization between the primary and secondary system(s) clocks is usually considered a prerequisite. The Phillips Laboratory has developed a software/hardware approach to the problem of decommutating an embedded asynchronous data stream without primary and secondary frame and clock synchronization. The methodology employed is easily implemented and adapted to many system configurations, and represents a low-cost option in the acquisition of subsystem data. More importantly, the use of such a system greatly reduces the amount of systems integration effort required to incorporate multiple subsystems into a host telemetry system.
    • IMAGE DATA COMPRESSION (USING DPCM)

      Karki, Maya; Shivashankar, H.N.; Rajangam, R.K.; Dept. of Electrical Engg., U.V.C.E., Bangalore; DSD-ISRO, Bangalore (International Foundation for Telemetering, 1991-11)
      Advances in computer technology and mass storage have paved the way for implementing advanced data compression techniques to improve the efficiency of transmission and storage of images. The present paper deals on the development of a data compression algorithm suitable for images received from satellites. The compression ratio of 1.91:1 is achieved with the proposed technique. The technique used is 1-D DPCM Coding. Hardware-relevant to coder has also been proposed.
    • RF SPECTRAL CHARACTERISTICS OF RANDOM PCM/FM AND PSK SIGNALS

      Law, E.L.; Pacific Missile Test Center (International Foundation for Telemetering, 1991-11)
      The telemetry radio frequency (RF) spectrum is rapidly becoming more crowded. Therefore, telemetry system engineers and frequency managers must become more knowledgeable about the RF spectral characteristics of telemetry signals. This paper presents methods to calculate the expected RF spectrum of random non-return-to-zero (NRZ) pulse code modulation (PCM)/frequency modulation (FM) and phase shift key (PSK) signals. The discussion includes the effects of bit rate, peak deviation, premodulation filtering, and spectrum analyzer resolution bandwidth. The methods are easily implemented using a personal computer and a spreadsheet program with graphics capability. Calculated spectra agree well with measured spectra. Equations are presented for accurately estimating the peak deviation and unmodulated carrier power of a random NRZ PCM/FM signal from the measured RF spectrum. Adjacent channel interference is also calculated. Key words: radio frequency spectral occupancy, pulse code modulation, frequency modulation, phase shift keying, premodulation filtering, adjacent channel interference.
    • INTERFRAME CODING OF VIDEO TELEMETRY SIGNALS

      Deutermann, Alan R.; Schaphorst, Richard A. (International Foundation for Telemetering, 1991-11)
      Television signals have been digitally transmitted for telemetry applications for several years. Reasons for digital transmission include the need for encryption, bandwidth compression, and the efficiency of time division multiplex. All digital coding techniques which have been employed to date, for video telemetry, are based on intraframe technology. In this case each TV frame is coded independently of the previous frames. In most video telemetry scenes there is a high degree of correlation between adjacent TV frames, and an interframe coding system which compresses the signal by reducing this frame-to-frame redundancy should be effective. This paper explores the potential advantages of interframe coding for video telemetry. Since this high level of compression typically causes the transmitted signal to be more sensitive to data link errors, the paper also examines advanced error control techniques.
    • SHIPBORNE TELEMETRY RECEIVING/RECORDING SYSTEM FOR ARLEIGH BURKE DDG 51 AEGIS CLASS DESTROYERS

      Kimbley, Robert; Bates, LeRoy; Naval Ship Weapon Systems Engineering Station (International Foundation for Telemetering, 1991-11)
      Portable Telemetry Data Receive/Record Sets (TDRRS) are temporarily installed in Navy ships to record and display data from tactical surface-to-air and surface-to-surface missiles (e.g., STANDARD, HARPOON, TOMAHAWK and SEA SPARROW). The Arleigh Burke DDG 51 AEGIS class Destroyer is the fleet’s newest Man-of-War. The first ship of this class, the USS Arleigh Burke (DDG 51), was recently commissioned on 4 July 1991. Permanent telemetry data RF and control transmission cabling systems will be installed in these Destroyers. The purpose of the dedicated cabling system is to deliver high quality telemetry data to the portable TDRRS. A dedicated quality interface guarantees reliable communications with the STANDARD Missile (SM) 2 during the pre-exit and initial airborne stages during missile launched from the ship’s Vertical Launch System (VLS). Previous ship classes depended on portable cables and equipment to provide for this function. Cables were brought through hatchways and bulkheads to the telemetry receiving and recording equipments. The DDG 51 AEGIS Class Destroyer uses a Collective Protection System (CPS) that provides for differential inside air pressure that is greater than the outside air pressure. This is intended to prevent chemical, biological, and nuclear contamination from entering the ship. To preserve CPS integrity, telemetry cabling is routed through airtight bulkhead connectors. This paper introduces the new integrated shipboard telemetry cable interface and the recently developed fleet telemetry receive and record system. Discussions will be provided on the SM 2 Vertical Launch System telemetry data transfer and the latest state-of-the-art receive and record equipment installed on the Arleigh Burke DDG 51 AEGIS Class Destroyers.
    • ON IMPLEMENTATION OF REMOTELY OPERATED UNMANNED TELEMETRY TRACKING SYSTEMS WITH FIBER OPTIC CABLE

      TURNER, WILLIAM C.; ELECTRO-MAGNETIC PROCESSES, INC. (International Foundation for Telemetering, 1991-11)
      The high cost of real estate in countries with expanding populations, coupled with the long range capability of modern weapon systems has resulted in the need to expand test ranges to remote desert areas or areas over sea water. In order to preclude the cost of duplicating existing test centers, and the high cost of manually operating ground tracking stations, the requirement for unmanned remotely controlled telemetry tracking systems has emerged. Until recently, implementation of such systems has been trivial because the microwave link had sufficient bandwidth. However, with the advent of multi-TM bands, encrypted T.V. video and dual-polarization diversity requirements, implementation of unmanned remote stations has become cumbersome, expensive and less reliable. For instance, a pair of dedicated computers are now required to remotely control as many as eight receivers and four diversity combiners. This paper analyzes the advantages, limitations and feasibility of remotely controlling a wide-band antenna/pedestal with the restriction that all frequency downconverters, receivers, and combiners be located at the test center where they can be manually controlled and monitored, and more readily maintained. A comparison is made between the use of coaxial cable and fiber-optic cable as short-haul (0.25 to 25 kilometers) RF transmission media.
    • ADVANCED TELEMETRY TRACKING SERVO SYSTEM

      HART, MICHAEL JAMES; INSTRUMENTATION DIRECTORATE, WHITE SANDS MISSILE RANGE, NM (International Foundation for Telemetering, 1991-11)
      The primary objective of the Advanced Telemetry Tracking System Integration and Development program at WSMR was the development and evaluation of an advanced, almost totally digital servo tracking and control system. This was satisfied by replacing the aging analog servo tracking and control system in one of WSMR’s seven Transportable Telemetry Acquisition Systems (TTAS) with a Digital Control Unit (DCU), an Antenna Control Unit (ACU), and other related equipment, and then evaluating the performance of the resultant digital tracking system, referred to as the Advanced TTAS (TTAS-A). The ACU is the primary interface between the operator and the DCU. Through the ACU, the TTAS-A operator has independent control over each pedestal axis (elevation and azimuth) involving the selection of tracking mode and servo bandwidth. The DCU reports various servo system status and warning conditions back to the operator through the ACU. In this paper, a discussion of the TTAS-A servo system, with emphasis upon hardware external to the DCU, is presented. This includes the operation of servo position and rate loops, system status and warning conditions, and a description of the operator-to-system interface via the ACU display and control functions.
    • SIGNAL TRANSMISSION FROM REMOTE TELEMETRY ANTENNAS USING WIDEBAND ANALOG FIBER OPTIC LINKS

      Matsuo, A.T.; Law, E.L.; Pacific Missile Test Center (International Foundation for Telemetering, 1991-11)
      This paper will present the results of an investigation of the feasibility of using broadband analog fiber optic technology to send telemetry antenna outputs from remote sites to a central site. The fiber optic hardware consisted of a prototype analog fiber optic transmitter and receiver plus 10 km of single-mode fiber. Laboratory tests were performed to simulate the performance in the real-world. The fiber optic system had a noise figure of 33.5 dB and a third order intercept point of 16.75 dBm. The use of this fiber optic system to transmit a 215-320 MHZ telemetry antenna downconverter output over a 10 km fiber would only degrade the quality of real-world telemetry signals by a few tenths of a decibel. Key words: analog fiber optic transmission, remote telemetry antennas.
    • A Useful Method of Error-Correction and Data Synthesis for Telemetry

      Chuan-hang, Fan; Xinan Electronic Engineering Institute, China (International Foundation for Telemetering, 1991-11)
      In the field of telemetry, data synthesis is an interesting problem for multi-beam and multi-receiver system. This paper introduces a useful method of coding and decoding for linear block code, and describes a decoding method of M repeatition codes---a special product code, the data synthesis is based on this method.
    • A Real-time Counting-measuring Method for PPM(PPK) Signals

      Xi-Hua, Li; Xinan Electronic Engineering Institute, China (International Foundation for Telemetering, 1991-11)
      On the disscussion of custom real-time counting-measuring method, this paper presents a new method suitable for the working condition of non-man duty, which possesses the feature of 100ns counting-measuring accuracy and high fidelity. In addition, the concept of “Signal-time/digit converter” is proposed for the first time and the principle and working procedure of this method are introduced in brief.
    • RT TELEMETRY NETWORK UPGRADE BASED ON ETHERNET

      Taylor, Gene; Vista Controls Corporation (International Foundation for Telemetering, 1991-11)
      New techniques for using Ethernet in real time systems are applicable to the typical requirements of high performance Telemetry installations. Most TM installations around the world today are currently implemented using specialized, high speed, point-to-point data paths which have reached their limits in performance. By using Ethernet in real time as a “Data Highway” path, system performance is optimized, and the effective life of a Telemetry system can be significantly extended. Additionally, by integrating a Local Area Network into the system, further advantages are realized. New graphics display hardware and software may be used to provide virtually an “offthe-shelf”, and very cost-effective major system upgrade. Meanwhile, little modification to the host processor hardware or software system is required. This paper examines these premises, and discusses several examples of major Telemetry systems which have made this upgrade.
    • COMPLEX FORMAT SYNCHRONIZATION AND DECOMMUTATION

      Thom, Gary A.; Aydin Computer and Monitor Division (International Foundation for Telemetering, 1991-11)
      Today's advanced commutation systems and on-board computers present a difficult challenge to many existing ground station systems. This paper describes various complex telemetry formats generated by these airborne systems and further describes methods for synchronizing and decommutating these formats.
    • AIRBORNE/SHIPBORNE PSK TELEMETRY DATA LINK

      CARLSON, JOHN R.; SCHMIDT, ARLEN; Aydin Computer and Monitor Division; Intera Systems, Ltd. (International Foundation for Telemetering, 1991-11)
      This paper describes the design considerations and methodology applied to solve the practical problems posed in the creation of a high bit rate telemetry relay system and specifically the techniques implemented to enhance signal to noise performance under adverse operational conditions.
    • FDDI AS AN EMERGING STANDARD FOR TELEMETRY SYSTEMS

      Taylor, Gene; Vista Controls Corporation (International Foundation for Telemetering, 1991-11)
      Various high performance fiber optic networks have been in existence and available now for over 10 years. Virtually all of them, until recently, have been designed around the “better idea” of some single company or engineer, and therefore were or became expensive, proprietary systems, with limited support, and limited or no growth potential. Many benefits were still realized by the users in spite of that; primarily in the areas of increased bandwidth, improved security, and the capability to have data transmission over long distances. However, after 5 years of continued development and refinement, the American National Standards Institute (ANSI) X3T9.5 committee has nearly completed acceptance and final approval of the Fiber Data Distributed Interface (FDDI) specifications. The new FDDI standards have already evidenced a tremendous and eager acceptance by the end user community, and are clearly destined to replace Ethernet as the most prevalent network media. FDDI also offers additional benefits specifically of interest to the telemetry market, and therefore represents an ideal Local Area Network (LAN) technology towards which any TM installation should migrate.
    • A PRECISION TRANSPORTABLE TRACKING TELEMETRY SYSTEM

      Morris, R.A.; Powell, W.R.; Bundick, S.N.; Scientific-Atlanta, Inc.; NASA/Goddard Space Flight Center (International Foundation for Telemetering, 1991-11)
      Changing mission requirements have forced NASA to procure a new generation of tracking telemetry system with performance and features greatly exceeding existing system capabilities in many areas. These requirements and the system that was designed to meet them are discussed. Initial results of system testing are presented.
    • A SIMULATOR OF PCM STREAM WITH HIGH DATA RATE

      Liang, LI Xian; QiShan, Zhang; Hui, Yang; BEIJING UNIVERSITY OF AERONAUTICS AND ASTRONAUTICS (International Foundation for Telemetering, 1991-11)
      The simulator of PCM data stream is an important apparatus. Without an advanced high data rate simulator, were not there a PCM system with advanced performance. After careful study, a simulator in laboratory of PCM stream with the data rate up to 30 Mbps is now designed. Our simulator differs from the traditional ones in the design principle and can bring all potentialities into play. It is more powerful in function, easier to test and more accurate in control. In the meanwhile, it can keep compatible with old simulators.