• A New Concept in Low Flutter High Environmental Recorders

      Hadady, R. E.; Bentley, R.; Kinelogic Corporation (International Foundation for Telemetering, 1967-10)
      To improve the performance of tape recorders operating under severe vibration, acceleration, and shock environments, two new flutter reduction design concepts have been developed: 1. Capstan servoing during the recording process to servo out flutter before it is recorded. 2. A new reel drive system in which the reels are coupled together to minimize tape tension variations and eliminate the possibility of throwing a tape loop. Test data on a prototype spaceborne recorder has proven the validity of the concept. The prototype has shown a capability to reduce flutter by factors ranging from 3 to 10 over conventional high-environrnent recorders. Typical flutter performance figures on the prototype (which accommodates 600 feet of 0.25" wide tape and operates at 30 ips) are: 0.36% p/p to 5000 Hz - on the bench 1.8% p/p to 5000 Hz - under environment (20 g rms random vibration) Time displacement errors (TDE) are ± 3 microseconds - on the bench ± 6 microseconds - under environment (20 g rms random vibration)
    • A Micropower Low Noise Integrated Operational Amplifier

      Pilling, D. J.; Wilson, G. H.; Fairchild Semiconductor (International Foundation for Telemetering, 1967-10)
      This paper describes a new integrated operational amplifier designed specifically for low standby power consumption. This amplifier is intended for use in portable instrument and telemetry equipment where low battery power drain is an important consideration. This high gain, low power, low noise operational amplifier is fabricated on a single silicon chip. Recent development of a low noise transistor process and a compatible high value resistor process led to its development. The highlights of its performance specifications are its high input impedance, low offset, low noise, and, for the first time in a commercially available operational amplifier, quiescent power consumption in the microwatt range. The circuit has excellent common mode and power supply rejection which, coupled with the high voltage process, insure operation over a supply voltage range of ±2.7 v to ±18 v. The amplifier, as shown in Figure 1, has a differential input and a single ended output. The general parameters of this amplifier are shown in Table 1.
    • Computer-Controlled Data Compression at 100 KC

      Schoen, Emil; Scientific Data Systems, Inc. (International Foundation for Telemetering, 1967-10)
      This paper describes a real-time computer-controlled telemetry system that can accommodate a 100 kc sample rate. The system's operating structure allows high-speed, asynchronous PCM data to be simultaneously decommutated, compressed, displayed, and merged. Data generated during test firings of the U. S. Navy's Poseidon missile will be reduced and processed by this system. Emphasis of the paper is on a description of the telemetry system's hardware and software.
    • Optimum Telemetry for a Meteorological Platform

      O'Bryant, Richard; Hoover, Wayne M.; Sharpe, John H.; Texas Instruments Incorporated (International Foundation for Telemetering, 1967-10)
      In order to predict the large-scale elements of the atmospheric circulation, measurements must be made on a global scale. One such method of measurement involves the telemetry of meteorological data from balloons floating at a constant level over the earth. The balloons are interrogated and their data relayed through a synchronous satellite to a central ground station. A study, funded by the Environmental Science Services Administration, has been made to determine the optimum electronics, in the sense of low cost, for the interrogation and telemetry systems within the constraints of minimum weight and power. This paper presents the problems of such a system, the approaches to the selection of an optimum system, the system selected, and a discussion of the implementation of the electronics of the selected system.
    • Single Side Band Translation Techniques for FM Data Acquisition Systems

      Roth, Allen R.; Lear Siegler, Inc. (International Foundation for Telemetering, 1967-10)
      A Single Side Band Data Translator has been developed and used successfully with any combination of reference and data frequencies from 100 Hz to 10 MHz. This translator, consisting of a computer calculated 90° phase difference network and field effect transistor multiplier circuits yielded undesired sideband signals which were at least 50 db below the desired sideband level over an input frequency range of ten to one. The translator was used to implement a system which recorded 75 time-correlated broadband data channels on a single track of a 5 MHz rotating head tape recorder. After de-translation, a signal to noise ratio of 60 db was measured with the recorder by-passed and a signal to noise ratio of 40 db was measured with all channels recorded. This paper presents the results of research carried out under Contract No. N123(60530)51701A sponsored by U. S. Navy.
    • A High Speed 10 Bit D/A Integrated Circuit

      Rudin, M. B.; O'Day, R. L.; Fairchild Semiconductor (International Foundation for Telemetering, 1967-10)
      A new high speed 10 Bit D/A integrated circuit is described as well as the basis for its design. Principal applications are given, notably a successive approximation A/D employing the circuit as its feedback D/A.
    • Delta-T Curves for Measuring Magnetic Tape Link Jitter

      Sos, J. Y.; Poland, W. B., Jr.; Cole, J. M.; Weiss, G.; Goddard Space Flight Center; U. S. Army, Electronics Command; Laboratory for Electronics Research, New York University (International Foundation for Telemetering, 1967-10)
      Magnetic instrumentation tape recording links are usually required to be substantially transparent data channels. One of the most important deviations from this requirement, both in FM and direct recording modes, occurs in the area of time delay error. A method for measuring the root-mean-square time delay error (Δ) between points on a record vs their separation in playback time (T) has been described in the literature (Refs. 1 and 2), but the implications and interpretation of this technique have not been fully developed. This paper derives the theoretical relationships between the Δ-T curve and the autocorrelation function of a pure sine wave recorded on the tape, and uses this correspondence to establish a connection between jitter spectra and Δ-T curves. A simple instrument for measuring these curves with high accuracy is described, and results of measurements made on a number of intermediate-band tape units in use at the Goddard Space Flight Center are presented. These measurements show that a low-mass tape unit may be superior to high mass units by more than an order of magnitude. The utility of the Δ-T measurement technique is discussed on the basis of its direct relationship to PCM and coherent recording applications, and its value as a standard means for evaluating time delay error in magnetic tape links is described. It is also shown that the technique can be used to determine FM modulation index.
    • Telemetry of Piston Parameters at Elevated Temperatures

      Slaffer, M.; Admiralty Engineering Laboratory (International Foundation for Telemetering, 1967-10)
      A system is described whereby piston information is continuously monitored using frequency modulation of carriers in the band 2 to 10 mc/s. The basic design of a miniaturised one channel transmit-ter for temperature measurement has been completed and practical details are given in the text. A thermistor was used as sensor. Trials with two operating channels have been carried out on a Lister engine over periods exceeding five hours without component replacement. The choice of high frequency band vras influenced by the desire to avoid the use of an iron cored sensor when the measurement of displacement was to be considered.
    • Data Collection Station for Automobile Safety Testing

      Goes, Ing F.; Hill, John J.; Volkswagen Works; Defense Electronics, Inc. (International Foundation for Telemetering, 1967-10)
      Increased emphasis on the incorporation of additional safety features in automobile designs has accelerated the adaptation of aerospace telemetry and datahandling techniques to the field of automotive performance testing. Described is a multiple link FM/FM telemetry ground station as used for acquisition of data from an automotive test track. System inputs adhere to aerospace telemetry standards, the output being a computer-compatible digital tape. Detailed attention is given to the high-speed sampling, data conversion, and digital tape formatting subsystem.
    • Ruggedized Quartz Oscillator Crystals for Gun-Launched Vehicles

      Liss, F. T.; Richardson, J. F.; Harry Diamond Laboratories (International Foundation for Telemetering, 1967-10)
      This paper describes a small hermetically sealed quartz oscillator crystal assembly capable of withstanding gun-launch accelerations of 30,000 g and some larger experimental units that have survived accelerations up to 70,000 g.
    • Carrier Synthesis from Perturbed DSB/SC Signals

      Simpson, R. S.; Tranter, W. H.; University of Alabama (International Foundation for Telemetering, 1967-10)
      In suppressed-carrier AM-baseband systems, the process of synthesizing carriers necessary for demodulation usually constitutes a difficult problem, especially when noise or recorder flutter is present. In this paper a particular scheme1, which synthesizes a demodulation carrier directly from a DSB/SC signal, is investigated for the purpose of determining the effect of noise and recorder flutter upon each of the various elements in the carrier synthesis loop. Curves are presented which illustrate the relationship between phase error in the demodulation carrier and various system parameters.
    • Automatic Real Time Data Quality Analysis

      Williard, Merwin W.; Symetrics Engineering (International Foundation for Telemetering, 1967-10)
      This paper deals with methods of detecting and displaying the quality of received telemetry data automatically and in real time. The most commonly used forms of telemetry multiplexing are considered in detail-with reference to application of the techniques to other similar forms of multiplexing. This paper is a result of a study -and hardware development which resulted in equipment now at Cape Kennedy and capable of detecting and displaying bit error rate on PCM telemetry, percentage of channel error on PAM and PDM telemetry and signal-to-noise ratio on FM/FM telemetry. The discussion -is oriented toward the theory of operation and techniques for automatic real time data quality analysis rather than toward the hardware. Methods of detecting and displaying the various data quality indicators is emphasized resulting in conclusions that in many instances relatively reliable data quality indications are possible in real time, but it must be realized that any indication of quality represents a review of conditions of the received signal over some finite averaging interval and thus no measurement can ever provide instantaneous quality indications.
    • UHF Telemetry System Development at White Sands Missile Range

      Chin, Ball; White Sands Missile Range (International Foundation for Telemetering, 1967-10)
      This paper describes UHF telemetry system development at White Sands Missile Range (WSMR), New Mexico, to achieve the telemetry operation change from VHF to UBF. Component and subsystem development is discussed. Results of the S-band equipment testing using the L-20 light aircraft, the F-100F jet fighter, POGO missile, and ATHENA re-entry vehicles are presented. Comparative analysis of missileborne telemetry data transmitted through both the standard VHF and the developmental S-band links are made.
    • Performance Standards for Eastern Test Range Telemetry Stations

      Harton, Paul L.; McRary, John W.; Pan American World Airways (International Foundation for Telemetering, 1967-10)
      An extensive engineering effort has been directed toward the rehabilitation of Eastern Test Range telemetry stations during the past five years. Initial planning began, at an earlier date) with studies of range user program plans. These studies have continued throughout the development period to assure a close agreement between range user needs for telemetry data and station capabilities. The plan to rehabilitate telemetry stations on the range has included airborne and shipborne systems, as well as the landbased stations. The stated needs of range users, and the projection of equipment trends formed the basis for specifying new telemetry systems for the Range. Design, production, initial tests, and installation followed in rapid sequence. An evaluation phase was then implemented to determine the operational readiness of the integrated systems and to establish the levels of performance at which each station should be assigned for support. Recent telemetry developments on the Eastern Test Range are briefly described, with emphasis on the launch area telemetry station, Tel 4. This general-purpose telemetry station must be operated in many different modes and configurations to accommodate the various signal structures that are used. Tests that have been used to estimate the station capabilities and limitations when it is configured to receive PAM/FM/FM and PCM/FM links are described as examples of the evaluation concept.
    • The Detection of PCM/FM

      Schilling, D. L.; Polytechnic Institute of Brooklyn (International Foundation for Telemetering, 1967-10)
      The calculation of the error rate resulting from the detection of PCM/FM is described. Emphasis is placed on characterizing the effect of the FM demodulator (FMD). The works of Schilling(l), Salz(2), and Klapper(3), are summarized and extended to yield error rate expressions when using an FM discriminator, Phase Locked Loop, or Frequency Demodulator Using Feedback (FCF). The "Integrate-and-Dump" and the Filter Detector are compared. The results indicate that in certain regions the error rate is due primarily to "smooth noise", and the FM demodulator followed by a PCM detector yields an error rate comparable to that obtained with a Matched-Filter (MF) detector. In other regions the error rate is shown to be due primarily to the spikes present at the FM demodulator output. The use of "Spike Detection and Correction" is discussed. It is shown that this technique results in reduced error rate in the "spike regions".
    • Double Sideband Suppressed Carrier Telemetry System

      Schmitt, F. J.; Lockheed Electronics Company (International Foundation for Telemetering, 1967-10)
      Vibration, shock, and acoustic data constitute one of the principal requirements for wideband telemetry. In order to permit a quantitative comparison of DSB/FM with the experimental results on constant bandwidth FM/FM for telemetry wideband noise-like data, a laboratory investigation has been conducted at WSMR. This paper reports experimental data on RF spectrum occupancy, intermodulation, performance against thermal noise, and some preliminary data on the effects of tape recording.
    • A Family of Linear Integrated Circuits for Telemetry

      Rudin, M. B.; O'Day, R. L.; Fairchild Semiconductor (International Foundation for Telemetering, 1967-10)
      Advances in monolithic circuit and process techniques are making available a steadily increasing number of linear integrated circuits especially applicable to telemetry systems. This paper reviews the principal types of telemetry systems--PCM, PAM, PDM, and FM/FM. It demonstrates that a compatible family of monolithic IC's in various stages of development at Fairchild can perform most of the circuit functions required by these systems--namely: (1) signal conditioning amplifiers, (2) multiplexer, (3) sample and hold, (4) unity gain A/D buffer amplifier, (5) A/D and PDM comparator, (6) D/A reference and switches, (7) D/A summing amplifier. In addition, future integration of functions not performed by the above circuits is discussed.
    • A Wide-Band Multichannel Transmission System for Use with 5 MHz Coaxial Land Lines

      McGarry, William P.; Data-Control Systems, Inc. (International Foundation for Telemetering, 1967-10)
      An increasing number of telemetry systems have considerable distance between receiving sites and main ground stations, resulting in a need for multichannel wide-band communications systems. An operational system is described which permits the wide-band DC to 120 kHz video or predetection IF 450 kHz ±150 kHz signals from six receivers to be transmitted over one land line to the remote ground station.
    • Possibilities of PCM-Encoding

      Hommel, Harr. R.; Liebelt, H.; Triendl, E.; Deutsche Versuchsanstalt fuer Luft- und Raumfahrt e.V. (International Foundation for Telemetering, 1967-10)
      This paper concerns with the various possibilities to encode space-signals for PCM-telemetry. It first reviews the logic design schemes to count binary events, to read out counted numbers, to compress data by floating point representation, and to convert analog signals with large dynamic ranges to binary numbers. Then, sane technical solutions, which are under development by DVL in cooperation with German industry, are described as examples. For these, heavy use of integrated circuits, monolythics, and hybrids was made.
    • Effects of Random Fluctuation Noise on FM and FDM/FM Reception

      Wachsman, R. H.; Baghdady, E. J.; ADCOM, Inc. (International Foundation for Telemetering, 1967-10)
      A tutorial review and analysis of the effects of random noise upon the output of a conventional FM demodulator is presented. The mechanism by which these effects are produced is conveniently brought out with the aid of phasor diagrams. Illustrative computations are given of the smooth and impulsive components of the output noise and of output signal-to-noise power ratios for various types of frequency modulation. Various types of thresholds are pointed out and the practical significance of threshold reduction as a system design optimization tool is discussed.