• TABS - an Asynchronous Block Serial Protocol for Multipoint Applications

      Schachter, Paul J.; AT&T Bell Laboratories (International Foundation for Telemetering, 1986-10)
      Since the early 1960’s, AT&T has established a trend toward centralized and remote operations of the transmission network. Thorough and continuous monitoring of global network properties can only be achieved through centralization. As a result, a secondary network has evolved in support of these monitoring functions. The “telemetry network” comprises a system of distributed processors dedicated to analyses of the transmission network, together with all necessary communication links. Monitoring access to the transmission network is provided at special interface points. Often the interface hardware is integrated into the transmission network element itself. AT&T uses a special protocol, TABS, the Telemetry Asynchronous Block Serial protocol, at the interface between the telemetry network and the transmission network.[1] TABS was designed by AT&T Bell Laboratories to optimize the performance and economics of this interface. In this paper, we describe the structure of that protocol, its performance properties and current implementations.

      Turner, William C.; Electro-Magnetic Processes, Inc. (International Foundation for Telemetering, 1986-10)
      Performance data taken on three candidate telemetry tracking antennas which employ significantly different beam scanning principles are presented. Measurements of antenna feed-induced phase noise were made at S-Band and compared.

      Kumar, Rajendra; California State University (International Foundation for Telemetering, 1986-10)
      A new least squares algorithm is proposed and investigated for fast frequency and phase acquisition of sinusoids in the presence of noise. This algorithm is a special case of more general adaptive parameter estimation techniques. The advantages of the algorithms are their conceptual simplicity, flexibility and applicability to general situations. For example, the frequency to be acquired can be time varying, and the noise can be non-gaussian, nonstationary and colored. As the proposed algorithm can be made recursive in the number of observations, it is not necessary to have a-priori knowledge of the received signal-to-noise ratio or to specify the measurement time. This would be required for batch processing techniques, such as the Fast Fourier Transform (FFT). The proposed algorithm improves the frequency estimate on a recursive basis as more and more observations are obtained. When the algorithm is applied in real time, it has the extra advantage that the observations need not be stored. The algorithm also yields a real time confidence measure as to the accuracy of the estimator.

      PIETERS, BERNARD; DIRECTION DES ESSAIS (International Foundation for Telemetering, 1986-10)
      The development of ballistic missiles and launch vehicles in the last twenty five years has required the engineering, perfecting and introduction of suitable testing and measuring facilities, more particularly telemetry equipment. We purpose to recall the major milestones of the evolution in this field of techniques throughout that period and to try to define some prospects for the future. We do not pretend to give a historical account, but only our thought on an industrial experience that we have lived through. Therefore, we entreat the reader’s indulgence for the non-exhaustive character of this paper and perhaps for some unintentional errors or distortions.

      SHVARTSMAN, VLADIMIR A.; Electronic Design & Research Co., Inc. (International Foundation for Telemetering, 1986-10)
      The introduction of a phase/frequency-locked loop (PFLL) technique made the task of transmitting information with a high degree of accuracy less cumbersome. The PFLL became possible after a high precision, continuous type phase/frequency-to-voltage converter/demodulator (PFVCD) was developed. It performance at a wide frequency band (DC-80 KHz), dynamic range up to 120 dB, and precision pulse width discrimination has made possible to build fast hopping PFLL based coherent timemultiplex PM-PM system with only few tenths of a degree of radians spacing between channels. A parallel type decoder was built to demodulate and separate individual channels. It employed the PFVCD which n-shape (ideal) bandpass characteristic and high level linearity eliminates crosstalk and minimizes distortion of an original signal.

      Knight, Paul; Pacific Missile Test Center (International Foundation for Telemetering, 1986-10)
      Since the late 1970’s the telemetry processing and display requirements of the Pacific Missile Test Center have been handled by the Telemetry Data Handling System. With the increasing use of embedded computers on test vehicles and the requirements to process and display larger volumes of data at higher data rates, many programs will soon exceed the capabilities of the Telemetry Data Handling System. The Telemetry Processing System is a replacement of the Telemetry Data Handling System that will be brought online in the Pacific Missile Test Center’s Telemetry Data Center in 1990. The Telemetry Processing System is required to meet the processing and display requirements of the Pacific Missile Test Center’s range users for the next decade. A discussion of the functional implementation and performance requirements of Telemetry Processing System is presented.

      Sargeant, H.; Interstate Electronics Corporation (International Foundation for Telemetering, 1986-10)
      Predetection recording of spread-spectrum (SS) signals such as GPS transmissions is a desirable objective for both users and developers of equipment designed to receive such signals. (GPS user-equipment development is a lengthy process during which signal simulators are only partially useful.) Upon playback, GPS signals are used by the same or modified receivers so that acquisition, processing, detection and tracking loops can be altered to optimize the receiver parameters. Development of predetect SS signal recording systems is difficult to achieve in practice. Such systems not only must be of suitable phase linearity to preserve the signal content to be extracted but sometimes must also preserve the exact signal-to-noise ratio (SNR) characteristics of the recorded signals. Existing conventional test equipment is unsuitable for deriving value judgments of the quality of a predetect recording system’s output because the SS signal has a negative SNR. This paper reveals that it is possible to use, for this purpose, tape recorders now available on many test ranges in combination with auxiliary equipment similar to that designed for the U.S. Navy’s TRIDENT Program (recording C/A-code data from in-flight missile translators). The basic techniques are described in some detail to enable potential users to understand the necessary equipment concepts and evaluate the author’s approach in terms of their own applications.

      Trover, William F.; Teledyne Controls (International Foundation for Telemetering, 1986-10)
      A realtime, multi-system, dynamic vehicle test capability has been developed for the testing of tanks and large vehicles under all possible conditions of terrain and environment. The systems, produced under a turnkey contract, include: a fixed base ground data processing system; a mobile ground station with the same processing capability; two vehicle-borne systems with on-board computing, recording and telemetry; and a large integrated software package for all four systems. The mobile ground station can be mounted on a rail car, a ship or the chassis of a diesel truck capable of operating across open field terrain. All four systems have computers and realtime EU data displays. The vehicle-borne systems can be assembled and mounted inside a tank turret for underwater testing. Optionally, they can be installed in an environmental enclosure mounted to the outside of the vehicle for open field testing or tests where the armament supply hardware must be installed inside the armored vehicle. Several special sensors were developed for the vehicle-borne instrumentation to permit measurement and display of terrain contour, ground speed, track efficiency, power train performance, vehicle direction, velocity and acceleration in 3-axes, vehicle attitude and stability, dynamic gun pointing accuracy, engine and transmission performance and operator reaction to the test requirements and the vehicle environment.

      BALCH, KRIS S.; Eastman Kodak (International Foundation for Telemetering, 1986-10)
      Today I will describe the application of the Autocorrelation function to the Magnetic Recording Channel. I will explain what is an autocorrelated function, how does it behave and where may it be applied in the Magnetic Recording channel. There will be a brief description of Kodak San Diego’s Autocorrelator and how we apply this technology. If I have done my job well at the end of this presentation you will have enough knowledge about autocorrelation to access your own application. Before I start, let me give a brief overview on the application of an Autocorrelator. The Autocorrelator can be used to collect information on signals in a magnetic recording system and display this information graphically as a statistical plot. Autocorrelation, in the time domain, is the counter part to a spectrum analyzer in the frequency domain (Fourier Pair). The information about the signal of interest must be stored for post analysis. This information called a database must then be processed by a computer. The computer passes the database through the autocorrelation algorithm and produces a second database. This second database represents a plot of the autocorrelated function. The next step is to plot the database on a video screen. This plot can be examined for periodicities, randomness, and relational influences on a captured signal. In our application, this signal is an error flag or a dropout flag. We want a statistical picture of the magnitude of errors and their relative frequency. The information gained from Autocorrelation can aid in solutions for: Error Correction Codes Media Evaluation/Qualifications Media Process Defect Identification Mechanical Eccentricities Modulation Code Performances System’s Figure of Merit To use a cliche, “one picture is worth a thousand words,” is exactly the point of the Autocorrelator’s graphical display. It yields information useful to those disciplines which often find difficulty in describing an event in understandable terms.
    • Data Synthesis in PCM Telemetry System

      Futang, Zhang; Xinan Electronic Engineering Institute, China (International Foundation for Telemetering, 1986-10)
      In the field of re-entry telemetry, data synthesis is an important research task for multibeam and multi-reseiver system. This paper presents a microcmputer-based method to synthesize PCM data in real-time. The performances of various criteria used in data synthesis systems are also analyzed here.

      DAHAN, MICHAEL; LOD ISRAEL (International Foundation for Telemetering, 1986-10)
      This paper describes an on-board PCM data acquisition and processing system using standard PCM units and commercial micro-computer equipments. A special interface, which was developed in order to allow a direct connection to PCM encoders, is also presented. It performs data buffering and decommutation prior to the data acquisition process. This approach facilitated the independent conduction of flight tests away from the users’ ground stations using a minimal investment. It helped to provide test results in flight or immediately after flights, thus shortening the flight test processing turn around time and contributing to expedite the overall flight test program.

      Hales, John C.; Boeing Aerospace Company (International Foundation for Telemetering, 1986-10)
      Standard video cassette recorders (VCR’s) are relatively inexpensive, small, and capable of recording large quantities of data for hours. The problem with using VCR’s to record pulse code modulated (PCM) digital data is that glitches are recorded in the serial data stream coincident with the video sync pulses. This problem can be solved by formating the PCM data stream and synchronizing the video sync pulses to the PCM data.

      RAJYALAKSHMI, P.S.; RAJANGAM, R.K.; ISRO SATELLITE CENTRE (International Foundation for Telemetering, 1986-10)
      In most transmission channels, bandwidth is at a premium and an important attribute of any good digital signalling scheme is to optimally utilise the bandwidth for transmitting the information. The Data Compression System in this way plays a significant role in the transmission of picture data from any Remote Sensing Satellite by exploiting the statistical properties of the imagery. The data rate required for transmission to ground can be reduced by using suitable compression technique. A data compression algorithm has been developed for processing the images of Indian Remote Sensing Satellite. Sample LANDSAT imagery and also a reference photo are used for evaluating the performance of the system. The reconstructed images are obtained after compression for 1.5 bits per pixel and 2 bits per pixel as against the original of 7 bits per pixel. The technique used is uni-dimensional Hadamard Transform Technique. The Histograms are computed for various pictures which are used as samples. This paper describes the development of such a hardware and software system and also indicates how hardware can be adopted for a two dimensional Hadamard Transform Technique.

      Anderson, William D.; Naval Air Test Center (International Foundation for Telemetering, 1986-10)
      The Naval Air Test Center, Range Directorate, has developed a Telemetry Relay Airborne Command System (TRACS) utilizing a Convair UC-880 aircraft. In its present configuration, the UC-880 can receive, record, and display telemetry data in real time; reshape and retransmit the telemetry data; act as a command center for TOMAHAWK cruise missile operations; provide radar range surveillance; remotely control instruments, cameras, emitters, and electronic countermeasures equipment on target hulks; provide inflight refueling of aircraft; process and display on CRT’s the maps of the area of operations and the missile profiles and tracks on the maps; and provide over-the-horizon target displays using a satellite communication system. This paper will present the development of the UC-880 TRACTS and the results of operations that utilized this system. The system characteristics, design constraints, and future plans will be discussed.

      Beffa, James C.; Ishii, T. Koryu; Marquette University (International Foundation for Telemetering, 1986-10)
      A millimeter wave radio responder was evaluated as a remote sensor of surface conductivity and laser light intensity. A 10 mm CdSe photocell was illuminated by a 1/4 mW, 632.8 nm He-Ne laser light. The photocell was not connected to anywhere. The terminals were left open. The photocell was interrogated by a remotely placed millimeter wave radio responder operated with the frequency of 69.6 GHz and the transmitter power of 3 mW. The millimeter wave radio responder was able to sense the radio echo from the surface of the photocell. The laser illuminated area on the photocell was only 2.86% of the entire active area, yet the radio responder output showed up to 15 dB difference between the laser spot on and off from the target. The minimum reflected signal change observed was 0.002 dB by tilting the target 20 degrees from the normal incidence of the millimeterwave beam. This was translated to be 0.025% of surface conductance change on the target. This remote sensing was done using an instrumentation of the sensitivity of !40 dBm. Thus, the usefulness and advantage of employing a millimeter wave radio responder for remote sensing of minute change in the surface conductivity and/or the laser light intensity have been demonstrated in this research.

      Russell, William P.; Naval Air Test Center (International Foundation for Telemetering, 1986-10)
      An integrated 1553 Data Bus Monitor (DBM) System has been developed at the Naval Air Test Center. The system is capable of monitoring six 1553A or B channels and provides, in separate PCM streams, selected parameter data and all message traffic on the data bus (thruput). Thruput data can be split to two tape tracks per channel for bandwidth conservation. Selected parameter formats can be entered at the flight line with a hand-held programmer which communicates to the DBM via an RS-232 interface. PCM outputs are available for telemetry as well as for on-board recording. Analog and discrete data is incorporated in the system with A/D inputs, parallel inputs, or serial entry of PCM data from a remote PCM system. A 1553 remote terminal provides data to the F-18 mission computer. Existing systems are being used on AMRAAM Development in the F-18 and in follow-on F-18 development at the Naval Air Test Center.
    • Review of Spectrum Support Information for U.S. Air Force Telemetry Equipment Development and Procurement

      BARNES, LARRY; U. S. Air Force Frequency Management Center (International Foundation for Telemetering, 1986-10)
      This paper presents a review of spectrum support information as it pertains to the development and procurement of U. S. Air Force Telemetry Equipment. Highlights of this review include: Definitions of terms used in this paper that are peculiar to spectrum management; frequency bands encouraged by the U. S. Air Force for Telemetry Equipment Development and Procurement for use in the United States including station, channeling, and bandwidth information; frequency bands discouraged by the U. S. Air Force for Telemetry Equipment Development and Procurement for use in the United States; summary of Telemetry Equipment Electromagnetic Compatibility (EMC) Parameters required when requesting certification of spectrum support in the United States; and finally a summary of telemetry equipment EMC standards associated with the certification of spectrum support in the United States.

      Lingerfelt, C. W.; ITT-Federal Electric Corporation (International Foundation for Telemetering, 1986-10)
      The processing of telemetry data received at the Western Test Range (WTR) requires the use of user supplied measurement attributes information. The telemetry streams currently being presented for support are from technologically advanced test vehicles which often involve complex measurement definition schemes. This document describes some of the current definition schemes and the processing required to obtain and utilize the data. The chaotic state of this environment is in no small part due to the lack of standardization of the measurement definition scheme and its media. The trend has been, and will continue to be, a condition of ever increasing complexity and variety unless some standardization is applied.

      Richards, William F.; University of Houston, University Park (International Foundation for Telemetering, 1986-10)
      A study has been undertaken to determine the feasability of dynamically controlling the input impedance of a microstrip antenna element by changing its reactive loading. The major applications of such an element would be for use in a scanned phased array. By changing the loading of individual elements appropriately, one could alter the active array impedance of the elements to compensate to some degree for the onset of scan blindness. While the ultimate feasability of such applications cannot yet be firmly established, a single element can be controlled using PIN diodes to effectively alter its input impedance. The generalized theory of loaded microstrip antennas has been used to predict the impedance of a variety of microstrip, antenna configurations with multiple loads. This work has shown the possibilities of changing the input impedance of the radiator over a wide range of values without affecting its resonant frequency or radiation pattern by moving a set of short-circuited loads from one position to another. Actual printed-circuit antennas were fabricated based on this design and good correlation was found between theory and experiment.

      Dalloul, Nizar M.; Baghdady, Elie J.; Boston University, College of Engineering Boston (International Foundation for Telemetering, 1986-10)
      This paper addresses the problem of analog multiplication for analog VLSI implementation, with particular emphasis on multiplication accuracy (low intrinsic noise) and speed. High-speed low noise analog multiplication for analog VLSI has very important implications in analog signal processing, signal generation, signal detection and ultra precise frequency and phase control. The various candidate multiplier mechanisms and circuits proposed todate are surveyed and a comprehensive comparison of them developed, leading to the conclusion that the Steerable Localized Injection Multiplier (SLIM) holds the greatest promise for low noise and high speed analog VLSI multiplication.