• Processing of NRZ PCM from 10 MB/Sec to 200 MB/Sec

      Gray, J. S.; Radiation Systems Division (International Foundation for Telemetering, 1970-10)
      The type of functions required to optimally process PCM plus noise are the same at low and high bit rates. At high bit rates there are severe constraints in synthesizing these functions due to limitations of present day devices and logic; and due to extrinsic effects of networks over broad baseband bandwidths. Techniques developed for signal conditioning, bit synchronization, group synchronization, and decommutation of NRZ PCM from 10 Mb/sec to 200 Mb/sec are presented. Multiple techniques were investigated in each area over the complete bit rate range of interest to ascertain performance versus complexity and cost effectiveness among different techniques at different bit rates.
    • Machine-to-Machine Compatability in Wideband recording

      Levy, Avner; Ampex Corporation (International Foundation for Telemetering, 1970-10)
    • A Universal L-Band Telemeter for Use on Artillery Projectiles and Gun Launched Research Probes

      Richard, Victor W.; Hadowanetz, Wasco; Aberdeen Proving Ground; Picatinny Arsenal (International Foundation for Telemetering, 1970-10)
      A UHF (1520 MHz) telemetry system for use with artillery projectiles and gun launched research probes is described. The feasibility of a universal telemeter (UTM) is demonstrated which is based on the use of modular plug-in components available to meet a variety of instrumentation requirements, including ogive and rear mounting, thus, eliminating the need for the development of a special projectile telemetry unit for each application of in-flight projectile performance monitoring or gun probe experiment. The special, ruggedized components and techniques for pre-flight high acceleration testing are described. The components described include: broadband, omnidirectional antennas for ogive and base mounting in projectiles; a high gain, all polarization, fan beam receiving antenna; stabilized, high efficiency UHF transmitters; miniaturized voltage controlled oscillators; 8 and 16 channel commutators; button cell and g-activated reserve cell batteries; shock resistant, electrically compatible radome and encapsulating materials; modular assembly cases; and ogive and base mounted telemeter test projectiles. The physical and electrical characteristics of the components of the telemetry system are presented, along with laboratory and field performance data obtained from firing standard, 155 mm, spinning projectiles, including the reception of signals while the projectile is in the gun barrel.
    • A Projectile Telemetry System for In-Barrel Data

      Bentley, R. D.; Ruttle, C. J.; Sandia Corporation (International Foundation for Telemetering, 1970-10)
      Sandia Corporation is developing a projectile telemetry system and required ground support to monitor the performance of components mounted in a 155 mm projectile. The telemetry system is to provide the data link required to monitor component performance during and following launch from a 155 mm "long-tom" cannon. The projectile experiences a 16,500g setback acceleration of 15 msec duration coupled with an angular acceleration of 328,000 rad/sec². A P band FM/FM telemetry system has been developed to provide a data link while the projectile is in the barrel as well as out of the barrel. The technique has been successfully tested in a 155 mm projectile with a setback acceleration of 12,500g 20 millisec duration and in a 81 mm mortar round with a setback acceleration of 7,000g 7.5 millisecond duration. A parachute recovery system is used to obtain a "soft" recovery of the 155 mm projectile mounted components and telemetry system.
    • Manned Space Flight Network Unified S-Bond System 1970

      Spearing, R. E.; Goddard Space Flight Center (International Foundation for Telemetering, 1970-10)
    • PCM Processing in Bandpass Signals

      Shaver, F. H.; Aerospace Corporation (International Foundation for Telemetering, 1970-10)
      Several types of errors are generated when a bandpass analog signal is sampled such that it can be encoded into a sequence of digital words. Two of these types of errors are particularly dependent on the frequency band occupied by the input signal. These are: (1) the aliasing errors due to generation of unwanted spectral components and, (2) pulse width errors due to the use of finite width, flat topped pulses when regenerating-the analog signal. Expressions are presented for the spectral densities and total power of these error sources. The particular dependence of each on the location in frequency of the input signal is investigated and discussed. Quantization noise and distortion due to the smoothing filter which is used to reconstruct the signal are not considered in this paper. It is determined that the aliasing noise power as a function of the ratio of the signal center frequency to the sampling frequency has a series of relative minimums and maximums. A relationship defining the ratios at which the minimums occur is presented. An approximate formulation for the sample pulse width error is presented which allows a simple estimate of its magnitude to be made without knowledge of the smoothing filter transform or the sampling frequency. Quantitative results are presented as a function of the percentage bandwidth of the signal and the ratio of the sample pulse duration to the period of the center frequency of the signal. The results of the analyses are interpreted as design constraints.
    • A Long Term Remote Intragastric pH, Temperature, Motility and Electrical Activity Monitoring System

      Wise, Leslie; Jones, Paul W.; Womack, G. J.; Ballinger, Walter F.; Washington University School of Medicine; McDonnel Douglas Astronautics Company (International Foundation for Telemetering, 1970-10)
      The system under development can monitor intragastric physiological changes over time periods exceeding fourteen days. Prior to this development, long term intragastric measurements were impossible in freely mobile subjects. The electronic instrumentation includes a tethered sensor capsule, automatic titration unit, telemetry system, and data display. The system requires minimal maintenance during the prolonged monitoring period. The sensor capsule utilizes a pH sensitive glass electrode with wet reference, a thermistor, a solid state pressure sensitive transducer, and impedance matching electronics which develop the physically related electrical signals. Signal acquisition is via tether hardline to the multichannel telemetry unit and subsequent RF transmission to a central data receiving system for display and storage. Automatic titration functions, a myograph to record voluntary muscle movement, and the measurement of skin resistance as an indicator of stress, may also be included in the telemetry data. Capsule system tests in vitro indicate these accuracies: ± 0.2 pH units over a range of 1 to 10 pH; ± 0.2°C over a temperature range of 25°C to 45°C; and ± 10% over a pressure range of 0 to 15 inches of water. Life tests of the capsule in vitro show useful life times of the order of 30 days. Preliminary human in vivo experiments have confirmed the capsule sensitivity and stability.
    • Use of an Error Model and a Simulation Program to Support Technical Management

      Brown, L. O.; Baum, R. F.; TRW Systems (International Foundation for Telemetering, 1970-10)
      This paper contains a discussion of various computer programs and their interconnection with an "error model" which have been developed and are being used by TRW, to form a very useful tool for technical management of a missile development and testing program. General aspects and requirements of the simulation and of some subroutines are outlined. A review of possible error sources is made emphasizing their effect on the frequency tracking performance of a typical instrumentation system such as the FPQ-6 radar operating with a radar transponder installed on the target.
    • A Computerized Data Management Methodology for the Minuteman Instrumentation System

      Foust, L. D.; TRW Systems (International Foundation for Telemetering, 1970-10)
      The tasks associated with Development Management of complex instrumentation systems, from initial concept to production, involves the utilization of very large quantities of data. It is impossible to acquire, process, and analyze this data entirely by manual means, therefore, automated data management systems have been conceived to solve this type of problem. The computerized data system developed by SAMSO MINUTEMAN Instrumentation System Engineering Management is described and is further illustrated by presenting some of the specific applications of the system.
    • Synchronization of Pseudo Noise Sequences for PCM Testing

      McClellan, Wade C.; Nichols, M. H.; White Sands Missile Range; Duke University (International Foundation for Telemetering, 1970-10)
      Coherent and noncoherent methods of synchronizing PN sequences for testing PCM telemetry receiving stations are compared. Test results are given for each method using a typical range S-band receiver, bit synchronizer and tape recorder. Effects of time-base-error from the tape are calculated and checked by test results. The laboratory tests indicated that for bit-error probabilities less than 0.01, the noncoherent synchronizer functioned satisfactorily.
    • Telemetry and Communications to Apollo Flight Controllers

      Glines, Alan; Lazzaro, Joseph A.; NASA Manned Spacecraft Center (International Foundation for Telemetering, 1970-10)
      The focus of this paper is on the use of telemetry and communications as essential tools in Apollo flight operations. The operational capabilities of the spacecraft and ground systems are described briefly to provide a background for detailing the management of the Apollo data system. The Mission Control Center is the central point of the operations and the recipient of all real-time Apollo data. Therefore, the operational structure within the mission operations control room is outlined briefly, with emphasis on the flight controllers who are the prime users and manipulators of telemetry data. The Instrumentation and Communications Officer (INCO) and the Operations and Procedures Officer (PROCEDURES) in the mission operations control room are responsible for the compatibility control of both the spacecraft and ground telemetry and communications systems. Their mission duties in four areas are detailed: (1) space-vehicle/ground communications compatibility, (2) telemetry subcarrier and bit-rate control, (3) spacecraft antenna management, and (4) data retrieval. The INCO and the PROCEDURES, through effective management of the many communications-systems modes of operation, maximize the amount of preferred real-time and playback data being transmitted to the Mission Control Center. The importance of the data is illustrated by specific mission events from the Apollo 11, 12, and 13 missions.
    • Digital FM Discriminator System

      Breikss, Ivars P.; Honeywell, Inc. (International Foundation for Telemetering, 1970-10)
      The Digital FM Discriminator described in this paper is used to demodulate FM signals with a high percentage (±40%) deviations. When contrasted to the conventional constant pulse width or the phase locked loop discriminators, the digital system has advantages of improved linearity and distortion performance. Additionally, because of the digital nature of the circuit, it requires no adjustment during setup or manufacture. The digital discriminator can be operated at any center frequency within the range of the integrated circuits used, provided that the proper ratio of the FM carrier center frequency and the clock frequency of the discriminator is maintained. In other words, the center frequency of the discriminator can be altered by altering the clock frequency. The digital discriminator provides an analog output which is a step-by-step reconstruction of the original modulating signal. In addition a digital word for each cycle of the FM carrier is generated corresponding to the amplitude of the modulating signal at that instant. The digital output is available in parallel as well as serial format.
    • A New Comcept for Equalization of Magnetic Tape Reproduce Systems

      Byers, Robert A.; Bell & Howell Company (International Foundation for Telemetering, 1970-10)
      A new approach to the problem of equalizing direct reproduce channels of instrumentation tape recorders has been developed. The technique employed utilizes active circuits and signal processing to develop the required transfer function. The principal advantage of the approach is that it requires only one operational adjustment to obtain the equalization characteristics. This allows a significant reduction in operator setup time and an increase in reliability by the reduction in the number of variable circuit elements. This is achieved by a slight increase in overall circuit complexity, the effect of which is minimized by the repetitive use of simple, functional circuits. The overall system approach is suitable for hybrid or monolithic technology.
    • Telemetering in Thermobiology: A Study of Mammalian Hair

      Davis, Stanley D.; Case Western Reserve University (International Foundation for Telemetering, 1970-10)
      An evaluation of the effectiveness of hair as insulation in a cold environment was performed using radio telemetry. Two adult male rats, telemetered for deep body temperature, were placed in an 18°C environment. After five days of monitoring temperature, food intake and body weight, each animal was shaved of all hair and observed an additional five days. Following shaving, both rats increased food intake, lost weight and showed lowered mean daily body temperatures, though in only one was the latter significantly lower. The increased metabolism after shaving was estimated to be between 25.2% and 51.1% greater than the preshave value in one animal, and between 23.4% and 32.9% in the other. The lowest increases were recorded in the rat tolerating the lower mean temperature. On the basis of food intake alone, metabolic demands of the shaven rats at 18°C were shown to be equal that of normal rats at 12°C. The advantages of using telemetry and continuous monitoring of temperature is discussed with regard to the results of this experiment.
    • International Telemetering Conference Proceedings, Volume 06 (1970)

      International Foundation for Telemetering, 1970-10
    • Quartz Crystals Units for High G Environments

      Bernstein, M.; U.S. Army Electronics Command (International Foundation for Telemetering, 1970-10)
      Quartz crystal units are commonly used to achieve frequency accuracy of the order of 100 parts per million or better. The usual crystal mechanical environments are quite benign compared with those encountered In high g telemetry, however, and the normal shock tests are only 100 g's. The preliminary, design of a ruggedized high frequency crystal unit is shown as well as test date on the behavior of these units when subjected to 15,000 g's of impact shock. A crystal resonator is quite fragile since at 20 MHz an AT resonator is only 3 thousandths of an inch in thickness. Higher frequency units appear to have a g limit only slightly in excess of 20,000 g's. At lower frequencies, the resonator is not the limiting element but the supports and bonds become unreliable. A trade-off must be made between a very stiff support, which will increase the acceptable g level, and the concomitant frequency instability due to changes in mechanical stress on the quartz resonator. These stress changes can be caused both by differential thermal expansion of the mount and quartz as well as by shock Induced effects.
    • Format and Address Equation Generation by Computer

      Leighou, R. O.; Hill, K. H.; Martin Marietta Corporation (International Foundation for Telemetering, 1970-10)
      Addressable remote multiplexed time division telemetry systems are being used more and more. Most of these systems operate with serial addresses generated by a central unit where each data source has a unique address. Thus the address sequence determines the particular format. In one type of system, the address sequence is determined by transfer logic between a counter and an address shift register. It takes several man-weeks of effort to develop a format and the logic equations to implement the address sequence for that format. To avoid this effort, an algorithm and computer program that generates the formats and the logic equations has been developed and is described. The program data inputs are: the basic format configuration of addresses (channels or data sources) per frame and the frames per master frame; and the number and types of channels at each samples per master frame (S/MF) rate. The program outputs are: address assignments by program ID, telemetry formats sequences with program ID, and the set equations for the address output shift register. Several checks are made during the program and if program restrictions are violated or format generation is impossible, error messages are printed and the program may be halted.
    • Manned Space Flight Network Telemetry System

      Underwood, Thomas C., Jr.; Goddard Space Flight Center (International Foundation for Telemetering, 1970-10)
      This paper discusses the Manned Space Flight Network (MSFN) Telemetry System as it has been developed through the Mercury, Gemini, and Apollo programs and is now being modified to meet Skylab, Earth Resources Technology Satellite (ERTS), and Apollo "J" mission (Apollo 16 and subsequent lunar missions) requirements. The existing telemetry system must be modified to meet the requirements of these future programs. This modification will consist of the implementation of automated configuration switching, centralized control of telemetry subsystems, tunable FM and PSK modulators/ demodulators, high frequency PCM signal conditioners, and the upgrading of both the wide band instrumentation magnetic tape recorders and the PCM decommutation capability. The resulting telemetry system, which will be capable of supporting various manned and unmanned space missions, is described here. Data flow diagrams are delineated and equipment electrical characteristics are discussed.
    • Disc Recording: Signal Acquisition and Reduction

      Calfee, R. W.; Data Disc, Incorporated (International Foundation for Telemetering, 1970-10)
      During the last several years, magnetic recording on plated discs has been developed and now can be applied to instrumentation recording. The disc recorder is available in a fixed head configuration for multichannel parallel recording and in a moving head configuration for one or two event parallel recording with extended time. The disc recorder can capture transient analog signals with bandwidth from DC to 6MHz or more for periods of time from microseconds to 20 seconds or more. The analog signal is stored on the disc after being processed through a proprietary period modulator. The disc recorder allows the user a natural base from which to reduce the analog data to computer understood words. Data reduction equivalent to 100 megabit conversion is possible at data rates compatible with the data device. Thus the disc recorder can capture transient analog signals and will allow simple data reduction.
    • Field Testing of Telemetry Systems

      Pickett, R. B.; Vandenberg Air Force Base (International Foundation for Telemetering, 1970-10)
      Tests have been developed and implemented at the Western Test Range for calibration of telemetry receiving systems. The tests serve an additional function as diagnostic aids.