• MODELS OF ANALOG VLSI LOW-NOISE MULTIPLIERS

      Dalloul, Nizar M.; Baghdady, Elie J.; Boston University, College of Engineering Boston (International Foundation for Telemetering, 1986-10)
      The class of Steerable Localized Injection Multipliers (SLIM) is known to be of high speed with least self-noise among all known analog multiplication techniques, and to be highly suited for VLSI implementation. SLIM design with predictable bounds on multiplication error due to intrinsic circuit noise requires valid noise generation modeling. Two models of SLIM noise sourcing are formulated: a small-signal model and a largesignal model. These noise models were simulated using SPICE to determine the power spectral density of SLIM output noise. The output power spectral density was shown to be flat over the frequency range up to 100MHZ, in agreement with prior experimental results.
    • QUATERNARY MODULAR ADDER WITH APPLICATION IN CORRELATIVE CODING TECHNIQUES

      Zhou, R.; Mavretic, A.; Boston University, College of Engineering (International Foundation for Telemetering, 1986-10)
      A general tendency in the digital communication systems is toward multi-level signalling in order to increase the information rate over a fixed bandwidth channel. Multiple valued logic circuits hold the promising potential for this application. including digital modulation, signal power spectrum shaping and coding techniques. Thispaper will present a novel design of quaternary modular adder circuit using multi-semiconductor technology — BI-CMOS process. This circuit demonstrates many advantages in improving noise margin and speed as well as in reducing transistor counts and chip areas. Some comparison with its binary counterpart and SPICE simulation results will also be given. Due to growing interest in multiple-level signalling combining with multiple-valued logic technology in digital communication systems, this paper will also discuss the application of modular adder in correlative coding techniques for spectral shaping. where quaternary modular adder performs efficiently in encoding input signal of non binary form at the transmitting end and in reconstructing the original data input at the receiving end. It also can allieviate the pin and interconnection requirements for equivalent information transfer.
    • DATA COMPRESSION IN PCM TELEMETRY SYSTEMS

      Smith, Daniel D.; Space Systems Division (International Foundation for Telemetering, 1986-10)
      The data capacity of aerospace PCM telemetry systems can be greatly improved by the application of data compression techniques, which exploit the redundancy in typical telemetry data. This paper describes the design concept for a compressed PCM (CPCM) telemetry system, and contrasts system design considerations to those involved in development of a conventional PCM system. Simulation results are presented depicting potential benefits from use of telemetry data compression on an upper-stage launch vehicle.
    • AN AIRBORNE TELEMETRY RELAY SYSTEM FOR THE GULF RANGE

      Zoledziowski, Severyn; LTV Aerospace and Defense (International Foundation for Telemetering, 1986-10)
      The Airborne Platform Telemetry Relay System (AP/TM) is currently being built for the Gulf Range Instrumentation System. The AP/TM will allow air-to-air missile test and training missions to be conducted beyond the line-of-sight of land-based instrumentation. The AP/TM is comprised of the following subsystems: C a Telemetry Data Relay C a Sea Surveillance Radar and Radar Data Link C a Drone Control Relay C a UHF Radio Relay The Telemetry Data Relay Subsystem will receive telemetry signals from five independent sources and will retransmit them to land based receiving sites. This subsystem contains a 75 square foot, electronically steerable, five beam phased array antenna and uses polarization diversity to eliminate polarization mismatch loss and to improve reception in the presence of multipath propagation. The AP/TM will also have the capability of relaying four channels of voice communications and drone tracking data and to perform sea surveillance of the mission area. The coordinates of targets detected by the radar will be relayed to the range control center over a high frequency (HF) data link. In addition to the airborne equipment, the system also includes a ground support instrumentation van which is used for pre- and post-flight checkout and maintenance.
    • A NEW METHOD SEARCHING OPTIMUM FRAME SYNCHRONIZATION CODES FOR PCM TELEMETRY SYSTEMS

      Qiu-Cheng, Xie; Ji-Qing, Ouyang; Nanjing Aeronautics Institute; Lin Quan Electrical Machinery Plant (International Foundation for Telemetering, 1986-10)
      In this paper, a new method searching optimum frame synchronization codes is presented. It is called “logical-sifting method”. This is a convenient method in comparison with the exhaustion technique.
    • ADAPTIVE PATTERN CONTROL OF A REACTIVELY LOADED, DUAL-MODE MICROSTRIP ANTENNA

      Richards, William F.; Long, Stuart A.; University of Houston-University Park (International Foundation for Telemetering, 1986-10)
      A dual mode microstrip antenna element has been investigated which has two independently excitable modes resonant at the same frequency. This element has been shown to be capable of producing a broadside maximum, a broadside null, or an end-fire type pattern by suitable choice of its reactive loads and suitable excitation of its degenerate modes. Appropriately located loads can be used to resonate modes normally resonant at quite different frequencies, at a single, common frequency. The results indicate that the nodal lines of the loaded element are accurately predicted by the generalized theory of loaded microstrip antennas, and that two modes can be excited independently of each other by feeding each mode along the nodal line of the other. To verify the theoretical predictions an actual dual mode microstrip element was fabricated and tested. The results of this experiment correlate well with the theoretical model with respect to the overall characteristics of the radiator.
    • AUTOMATIC COMPUTER DATA BASE ENTRY AND SETUP OF A DECOMMUTATION SYSTEM

      Rogers, M. Kimberley; Lamb, Gina L.; Ashmore, James H.; Schuh, Richard A.; General Dynamics Convair Division; Loral Instrumentation (International Foundation for Telemetering, 1986-10)
      This paper presents a method developed to automate the data base entry and setup of the ADS 100 Decommutation System. Automation was accomplished by interfacing an existing RS-232C port with a VAX computer. Other available interface options are considered. The automated system provides a method for rapid data entry while minimizing errors. Automation also eliminates the continuing requirement for a skilled ADS 100 programmer. Additional topics reviewed are the various problems encountered while developing the interface. Also discussed is the development and interface of host computer software, including the predefined ADS 100 record structures. The final result is a complete and accurate digital data base setup in the ADS 100 system.
    • A REVIEW OF MULTIPLE BEAM ANTENNA ARRAY TRADEOFFS

      Hansen, R. C.; Pacific Missile Test Center (International Foundation for Telemetering, 1986-10)
      Telemetry instrumentation antennas often require several beams to allow simultaneous tracking of several targets. These multiple beams can be provided several ways, including multiple beam antennas and phased arrays. A brief review of the tradeoffs involved in implementing multiple beams with phased arrays is given. Planar arrays, which may be combined to provide wide angular coverage, include a corporate feed giving multiple independent beams, a distributed configuration with independent beams, the Butler beamformer, and the Gent-Rotman beamformer. Conformal implementations include cylindrical and conical arrays, and the spherical dome lens.
    • MEANINGFUL FM TRANSMITTER MODULATION LINEARITY MEASUREMENTS

      Jeske, Harold O.; Sandia National Laboratories (International Foundation for Telemetering, 1986-10)
      In Frequency Division Multiplex (FDM) systems, nonlinearities in the modulation and demodulation processes of the transmission system produce intermodulation (IM) products which are effectively added to the desired modulation. The effect of these added products is the degradation of data accuracy in the form of noise on the subcarrier data. Currently there are no standard test procedures or specifications that permit the prediction of the level of these IM products during system design. The characterization of transmitter modulation linearity by the measurement of IM, or cross-products, produced by simultaneous modulation by two tones, is considered ideal. This is because the test conditions can closely simulate the highest modulation level subcarriers used and the necessary demodulation equipment can he readily calibrated using common frequency modulated sources. The modulation tones used are both in the upper portion of the transmission system’s baseband and at a modulation level near the level of intended use. Measurement of only the difference frequency IM component, (f !f ), is considered 2 1 adequate for the determination of 2nd order nonlinearities. The 3rd order IM components are measured only at (2f !f ) and (2f !f ) and are normally found to be of equal 1 2 2 1 amplitudes with FM transmitters. All higher order products, as well as direct harmonics, are ignored. From the three IM level measurements, and the two desired tones, the 2nd and 3rd order modulation intercept points (IP and IP ) are determined in essentially the 2 3 same manner as the intercept point, or IP, that is common in specifying the linearity of broadband RF amplifiers. When the amplitude of the various signal and IM components are plotted on log-log scales, the desired signals have a slope of one while the 2nd and 3rd order products have slopes of two and three respectively. On log-log plots the intercept point is the modulation level at which extensions of the low level values of the IM components meet the extension of the desired modulation level. Once the IP values are determined, they may be readily used for system IM calculations. Measured IM levels in a sixteen channel FDM system compared very favorably with predicted levels using the IP values obtained from two-tone tests. The nonlinearities of the demodulator employed in the test system may be evaluated by the use of the “beat” frequency of two independently modulated FM signal sources as the required input to the demodulator. The IM products in the demodulator output in this case are due only to the demodulator’s transfer characteristics. IM product levels of the test system greater than 60 dB below the simultaneous modulation level of ±300 kHz each by 400 and 450 kHz tones are obtained at Sandia Laboratories. The use of two-tone IM tests for the evaluation and specification of FM transmitter modulation linearity is strongly recommended.
    • SYSTEMS AND METHODS TO REDUCE DATA PROCESSING TURNAROUND TIME

      Crolene, Robert; Pacific Missile Test Center (International Foundation for Telemetering, 1986-10)
      Weapon system complexity and its data expression have become a central issue for the Range Directorate at the Pacific Missile Test Center (PMTC). Increasing data complexity and data product turnaround requirements have created a technological push-pull on traditional data processing methods. Several possible responses are discussed which include distributed front and back end processing relative to the large mainframes, and increasing use of artificial intelligence techniques in the data reduction area. These methods are going through progressive steps of implementation at PMTC with some notable success.
    • AN APPROACH TO TELEMETRY SYSTEM ARCHITECTURE

      Kulkarni, A.D.; Vikram Sarabhai Space Centre (International Foundation for Telemetering, 1986-10)
      Availability of low cost microcomputers, LSI devices have made it necessary to recast the architecture of aerospace telemetry system to realize all the attendant benefits. System constraints and the resultant hardware design are described in this paper.
    • U. S. Air Force Satellite Control Network Evolution

      Walker, Donald; Air Force Satellite Control Network (International Foundation for Telemetering, 1986-10)
      This paper traces the evolution of the Air Force Satellite Control Network (AFSCN) from its inception twenty-seven years ago to the present, and provides a view of its continuing evolution in the future. This evolution has come about in response to expanding requirements on satellite control, reflecting the nation’s increasing reliance on Department of Defense (DoD) Space Systems. Network improvements planned years ago are becoming realities: the Consolidated Space Operations Center is beginning operations; the Data System Modernization program, bringing modern data processing equipment and software to the network, is undergoing operational testing; and the modernization of the remote tracking stations through the Automated Remote Tracking Station development is proceeding on schedule. The recently completed Satellite Control Architecture Study initiated by the Air Staff provides a roadmap for meeting anticipated future requirements for the next thirty years. Cornerstones of this study are the introduction of EHF and SHF communications for space control functions, and satellite crosslink communications; the planning for these has been merged in the Enhanced Telemetry, Tracking and Commanding (ETT&C) system concept. This and other evolutionary developments have the objectives of providing reliable, secure communications and control, with reduced reliance on overseas assets, while developing new operational capabilities. Through these efforts, the AFSCN will provide assured control of DoD space systems commensurate with the Air Force policy of assured access to space.
    • STAR TOPOLOGY SPACECRAFT DATA BUS

      Garas, Anthony G.; Sperry Corporation (International Foundation for Telemetering, 1986-10)
      Significant advances in processing power and hardware miniaturization for aerospace applications has led to new distributed avionics architectures. These architectures have driven system data transmission requirements to the point where current data communications and interconnect technologies are marginal or inadequate. Advanced spacecraft including Space Station and SDI platforms have identified the need for distributed processing and real time control, requiring large and complex data communications networks with bus data rates in the 100 to 500 MBPS range. To address this need a new communications protocol has been developed to provide high data rate and very short transport delay performance. The protocol is implemented using a star topology fiber optic data bus. During the design of this system for spacecraft data bus applications, particular attention was paid to system robustness, redundancy, fault tolerance, autonomy, and error control. The salient system design, hardware configuration, and performance of an eight node demonstration network jointly developed by NASA Goddard and Sperry Corporation are presented in this paper.
    • CROSS-MODULATION INTERFERENCE AVOIDANCE FOR ENHANCED PERFORMANCE OF DEEP SPACE TELEMETRY SYSTEMS

      Nguyen, Tien; Mathur, Ashok; California Institute of Technology (International Foundation for Telemetering, 1986-10)
      In this paper we investigate the performance degradation of the NASA Deep Space Network (DSN) telemetry receiving system for two data channels in the presence of cross-modulation interference. It is shown that the sub-carrier waveforms and/or frequencies can be selected to suppress the cross-modulation interference for enhanced deep-space telemetry performance. The application of this study is suggested for a simultaneous telemetry and ranging as well as telecommand and ranging operations. Recommendations as to use of specific subcarrier waveforms and frequencies to suppress cross-modulation interference are made to the international Consultative Committee for Space Data Systems (CCSDS) for consideration in the future standards systems.
    • THE ADVENT OF D-1 TECHNOLOGY

      Wood, Tracy G.; Ampex Corporation (International Foundation for Telemetering, 1986-10)
      The advent of the D-1 cassette standard will have a profound impact upon the instrumentation tape recording industry starting in about 1990. Under the auspices of the Society of Motion Picture and Television Engineers (SMPTE) and the European Broadcast Union (EBU), broadcasters, media manufacturers and television recorder manufacturers have developed a series of standards governing digital recording of television signals using a set of standard, high-quality cassettes. To support television applications, two specific formats are necessary to cover the marketplace; a “component” format, which is independent of the television standard and compatible with a digital studio, and a “composite” format which is dependent upon the national format and is compatible with analog studios found today. Standards are in place covering 4:2:2 digital component recording. Proposals covering composite digital recording formats are now being discussed in the industry. As the only U.S. recorder manufacturer with a declared intent to manufacture hardware for the television industry to these standards, Ampex has participated in the generation of these standards. This paper will discuss the cassette and data standards which have been created for the television industry. Where deficiencies and limitations in those standards exist for data recording, these will be pointed out.
    • DATA ACQUISITION TECHNIQUES USED FOR MIL-STD-1553 DATA

      Penharlow, David; Aydin Vector Division (International Foundation for Telemetering, 1986-10)
      This paper will address various applications and methods used for the acquisition, recording, and telemetering of data from the MIL-STD-1553 avionic multiplexer data bus installations in aircraft, missiles, and other vehicles. Discussions of the problems encountered and hardware utilized in current applications are reviewed. The innovative techniques used to optimize system performance, and future trends for program requirements are also discussed.
    • THE CO-EXISTENCE OF SPREAD SPECTRUM RANGING SIGNAL IN INDIAN NATIONAL SATELLITE-1B (INSAT-IB) WITH TV OR SCPC CHANNELS

      Lal, P.M.C.; Palsule, V.S.; Kumar, Pramod; Indian Space Research Organization (International Foundation for Telemetering, 1986-10)
      Spread Spectrum Systems have the potential of sharing the frequency spectrum with broadcasting, telephony and data communications services due to their low power density signalling. The study of feasibility of co-existence of Direct Sequence Spread Spectrum ranging signal with TV or SCPC carriers in a common satellite transponder is presented in this paper. The suitability of this type of ranging for Indian National Satellite-IB (INSAT-IB) system from Master Control Facility (MCF), Hassan, India has been examined. The mutual interference effects between spread spectrum ranging signal and TV or SCPC services through various sizes of earth stations in INSAT network have been calculated. The study indicates that simultaneous accurate range measurement by spread spectrum technique from control earth station is possible without any significant degradation in signal quality of TV or SCPC services.
    • HIGH SPEED, WIDE BANDWIDTH SIGNAL DETECTION AND FREQUENCY ESTIMATION

      Caprio, James R.; Nystrom, Lennart; Comptek Research; Anaren Microwave (International Foundation for Telemetering, 1986-10)
      A digital frequency discriminator (DFD) of the delay-correlator type is described. The device is shown to have an instantaneous frequency measurement capability on very short pulses. The theoretical performance of the DFD in a noisy background is derived and shown to compare favorably with measured results.
    • REALISTIC TARGETS FOR ARMY TEST AND EVALUATION

      MILWAY, WILLIAM B.; HQ, USATECOM (International Foundation for Telemetering, 1986-10)
      The use of some type of target as an aiming point has been an essential part of weapon system testing since the beginning of history. Today, with the complex arsenal of high technology weapons used by the Army, the need for targets is critical. There is currently a shortfall in the performance that can be obtained from existing targets. The development of new and improved targets and target control systems will be a high priority task in the next decade.
    • HIGH-PERFORMANCE LANDSAT/SPOT DUAL S-/XBAND TELEMETRY TRACKING AND RECEIVING SYSTEM

      Bollermann, Bruce; Harshbarger, Roger; Haynie, Mark; Pande, Kailash; SPACE DATA CORPORATION (International Foundation for Telemetering, 1986-10)
      A high-performance dual S/X-band telemetry tracking and receiving system has been developed to provide a low-cost earth station for receiving high-resolution data from current and future LANDSAT/Spot polar orbiting satellites. The antenna system consists of a dual S/X-band telemetry tracking feed in a Cassegrain configuration with a 10-meter parabolic reflector designed for 100 mph wind loading and 10 deg/sec accelerations. The 2 antenna system is mounted to a newly-developed elevation-over-azimuth tracking pedestal, which incorporates the latest technology in a dual brushless d.c. servo motor torque-biased drive train for each axis. This drive train provides an exceptionally wide dynamic range in trlcking velocities for very slow horizon tracking and very fast velocities for near-overhead passes. A microprocessor-based servo control system using the latest state variables feedback and adaptive control techniques is used to provide accurate tracking for both slow and fast rates. A 15-km satellite pass distance from overhead is used as a control system design criterion. For the narrow beamwidth X-band track this requires an acceleration error of less than 0.100 degree and an acceleration error constant of at least 90 sec . The requirement for a high-performance servo system with the low -2 structural resonances of a large antenna constitutes a difficult stability problem.