• 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.

      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.

      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.

      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.

      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.

      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.

      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.

      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.

      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.

      Hull, Roy T., Jr.; Naval Undersea Warfare Engineering Station (International Foundation for Telemetering, 1991-11)
      The performance testing of underseas weapons involves many of the same challenges as for other “smart” systems. Data sets on the order of GigaBytes must be extracted, processed, analyzed, and stored. A few KiloBytes of significant information must be efficiently identified and accessed for analysis out of the great mass of data. Data from various sources must be time correlated and fused together to allow full analysis of the complex interactions which lead to a given test result. The fact that the various sources all use different formats and medias just adds to the fun. Testing of underseas weapons also involves some unique problems. Since real time data transmission is not practical; the vast bulk of the test data is recorded and then recovered with the vehicle at the end of the test. Acoustics are relied on for identification and ranging. As systems continue to get smarter; the rates, capacities, and “smarts” of the equipment and software used to process test data must similarly increase. The NUWES telemetry capabilities developed to test and analyze underseas weapons could be of use on other government related projects. “Key words: Telemetry, data processing, data analysis, undersea weapons, smart weapons, torpedoes, performance testing.”

      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.

      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.

      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.

      BORDAS, Jean-Claude; LEBLANC, Jean-François; ELECTRICITE DE FRANCE; SCHLUMBERGER Industries (International Foundation for Telemetering, 1991-11)
      For the last dozen years, ELECTRICITE DE FRANCE has been using a digital telematry system mountable on the rotors of its generating machines in case of acceptance tests or after technical hitch, under difficult environmental conditions (125 degrees C and centrifugal acceleration of 100,000 m/s ). This system, manufactured by 2 SCHLUMBERGER, has proved itself in many test programs on high-power electrical motors, primary pumps of PWR reactors, steam turbines, alternators, etc. Today, the need is growing towards operational monitoring of equipment. Using this type of equipment in a monitoring system is a greater challenge. In fact, it is necessary to obtain an MTBF longer than the fuel refilling period (approximately 18 months) to make significant savings in product costs. A technological upgrade of the existing product was undertaken in late 1989. A very effective product capable of meeting the needs expressed is now available on the market. The system can be used to build systems with 1 to 63 channels with pass-bands ranging from 250 Hz to 10 kHz and very high precision (approximately 0.1%), under the above-mentioned environmental conditions. Its size, low power consumption, range of operating temperatures (-20 to 125 degrees C), resolution (12 bits), adaptability and capability of operating under conditions of acceleration and vibrations (100,000 M/s and 1000 m/s from 20 to 1000 Hz), make it a 2 2 unique product of its type. Although designed for use on rotating machines, these devices, thanks to the designs and technologies used, are compatible with other types of applications. The central equipment is also modular, a change in the structure of the rotor-mounted system does not call any of the investments into question; only the equipment’s software configuration is modified. A full line of standard equipment for reception, decommutation, recording and processing is available. This paper is intended to show how this product was developed so as to meet the main constraints of a system mounted on rotating machines. Problems related to installation on the machine, the power supply to the system and data transmission are not dealt with here. A short video film will illustrate our analysis.

      Carden, Frank; New Mexico State University (International Foundation for Telemetering, 1991-11)
      Design parameters for a FM/FM telemetry system are determined in terms of the IRIG specifications for proportional bandwidth channels. Three mathematical models used by designers of the above processes are extended and compared. That is, FM multitone models are used to establish the relationship between frequency deviations, modulation indices, signal-to-noise and IF bandwidth for the IRIG channels. Since spectral efficiency and signal quality are of major importance, a goal of the design is to have a minimum IF bandwidth, while fixing as large as possible the values of the modulation indices for the subcarriers modulating the carrier in order to achieve as large as needed output signal-to-noise ratio.
    • Software Development of a Standardized User Interface for the HAFB Telemetry Ground Station

      Seebold, Otto P., Jr.; Physical Science Laboratory (International Foundation for Telemetering, 1991-11)
      The Systems Development (SD) group at the Physical Science Laboratory (PSL) has developed and integrated many telemetry data acquisition systems for both government and non-government customers. PSL/SD normally only develops telemetry hardware when there is no commercially viable equipment available within the cost restraints of the contract. Over the years, PSL/SD has chosen the best commercially available hardware that fulfilled the requirements of the specific project. Each project presented a unique set of requirements that necessitated a custom designed user interface for the setup of each vendor’s telemetry hardware. PSL found that it was redeveloping the telemetry definition user interface for each vendor’s product and this was consuming a larger percentage of the development budget. Therefore, in the development of the user interface for Holloman Air Force Base (HAFB) Telemetry Processing System (TPS), PSL decided to develop a user interface that could be easily modified to support new telemetry hardware with a minimum effort and present a common user feel to all future telemetry systems.

      JARYNOWSKI, ROBERT J.; New Mexico State University (International Foundation for Telemetering, 1991-11)
      A VME computer can be used to provide the basis for a telemetry data processing station. Using “off-the-shelf cards” the designer is able to build up a front end that meet several of the data processing requirements. The ease in interfacing to the VME bus also provides a convenient platform for the development of highly specialized interfaces requiring programmable control. The results are a low-cost highperformance system that is easily expandable as needs and/or technology grow. Based on this strategy, the Physical Science Laboratory (PSL) at New Mexico State University developed a multichannel high-speed analog-to-digital converter (ADC) assembly on a single VME board. The design approach used at PSL to develop the VME-based ADC is discussed in an effort to describe both developments in analog-to-digital conversion integrated circuits and the use of a VME CPU to control them for data processing purposes.

      Schaeffer, Paul J.; ARIA Programs Division (International Foundation for Telemetering, 1991-11)
      Recent advances in acoustic detection and array processing have led to a new, state of the art, Sonobuoy Missile Impact Location System (SMILS). This system was developed for the 4950th Test Wing by E-Systems and the Johns Hopkins University Applied Physics Laboratory to support ballistic missile testing in broad ocean areas. The hardware and software required to perform the SMILS mission were developed in two different areas: 1) The flight system, installed aboard the Advanced Range Instrumentation Aircraft (ARIA), which provides everything necessary to guide the aircraft to the target area of Deep Ocean Transponders (DOTs), deploy sonobuoys, recover signals from the sonobuoys, and to process the recovered signals. The sonobuoy positions and impact locations of reentry vehicles are determined aboard the aircraft in real-time by telemetering the acoustic signals sent from the sonobuoys via Radio Frequency (RF) link to the aircraft. These acoustic signals are also recorded on analog tape in the aircraft. 2) The Post Mission Analysis System (PMAS), located at the 4950th Test Wing, processes the analog tapes recorded by the aircraft to do more sophisticated Processing than that performed on the aircraft, providing higher resolution of impact times and positions. This paper addressees the theory of PMAS operation and the specific approach used to perform automated acoustic detection of both narrow and wide band acoustic signals. It also addressees the processing technique employed to determine sonobuoy navigation and impact scoring.

      Law, Eugene L.; Pacific Missile Test Center (International Foundation for Telemetering, 1991-11)
      There is a requirement to digitize certain wide-band analog signals in telemetry applications. Typically, an analog-to-digital converter (ADC) with eight or more bits of resolution is used. The resulting signal requires a much larger transmission bandwidth than the original analog signal. The frequency domain information is of primary interest for many applications. In these cases, there are several methods for minimizing the transmitted bandwidth. One method is to perform fast fourier transforms (FFTs) on the signals and only transmit information about the largest signals. The disadvantages of this approach include: relatively long time delay before transmission, resolution bandwidth fixed when FFT performed (unless phase information is also transmitted), and extra complexity in the telemeter. This paper will discuss some effects of minimizing the transmitted bandwidth by quantizing to a small number of bits. The performance will also be compared with analog frequency modulation (FM). Measured performance will be presented for four different input signals and one-, three-, and eight-bit quantization. These signals are amplitude modulation, angle modulation, sum of sine waves, and frequency sweep. The test setup is shown in figure 1. The analyses presented in this paper were performed using either fast fourier transforms (FFTs) or a Kay DSP Sonagraph. The FFT length was 1024 points and a Hann (cosine) window was used. The analysis hardware used for these tests has an analog input, therefore, all digitized signals were converted to analog signals before analysis. The signals were low pass filtered before analysis to minimize aliasing in the analysis and display process.
    • A PC-Based Telemetry System for Acquiring and Reducing Data from Multiple PCM Streams

      Simms, D. A.; Butterfield, C. P.; Solar Energy Research Institute (International Foundation for Telemetering, 1991-11)
      The Solar Energy Research Institute’s (SERI) Wind Research Program is using Pulse Code Modulation (PCM) telemetry data-acquisition systems to study horizontal-axis wind turbines. Many PCM systems are combined for use in test installations that require accurate measurements from a variety of different locations. SERI has found them ideal for data-acquisition from multiple wind turbines and meteorological towers in wind parks. A major problem has been in providing the capability to quickly combine and examine incoming data from multiple PCM sources in the field. To solve this problem, SERI has developed a low-cost PC-based PCM telemetry data-reduction system to facilitate quick, in-the-field multiple-channel data analysis. Called the “PC-PCM System,” it consists of two basic components. First, PC-compatible hardware boards are used to decode and combine multiple PCM data streams. Up to four hardware boards can be installed in a single PC, which provides the capability to combine data from four PCM streams directly to PC disk or memory. Each stream can have up to 62 data channels. Second, a software package written for use under DOS was developed to simplify data-acquisition control and management. The software provides a quick, easy-to-use interface between the PC and multiple PCM data streams. Called the “Quick-Look Data Management Program,” it is a comprehensive menu-driven package used to organize, acquire, process, and display information from incoming PCM data streams. This paper describes both hardware and software aspects of the SERI PC-PCM system, concentrating on features that make it useful in an experiment test environment to quickly examine and verify incoming data from multiple PCM streams. Also discussed are problems and techniques associated with PC-based telemetry data-acquisition, processing, and real-time display.