• Analysis of FM/FM Transmission Line Distortion

      Mohnkern, Gerald L.; N.A.S.A. (International Foundation for Telemetering, 1965-05)
      An IBM 1620 computer was programmed to evaluate the effects which the variation of propagation velocity and attenuation in coaxial cables has on a frequency modulated carrier. For a nine mile length of RG-8A/U the distortion of 70kc modulation on a 1 mc carrier was severe, while for a 10 mc carrier the distortion was negligible. A typical system using 4, 6, and 9 mc carriers on a single cable was evaluated.
    • Rocket Trajectory Analysis from Telemetered Acceleration and Attitude Data

      Cooper, Oscar L.; Research Foundation, Oklahoma State University (International Foundation for Telemetering, 1965-05)
      Double integration of the longitudinal acceleration of a sounding rocket is useful as a simple means of determining its trajectory. Reasonably accurate altitude calculations can be made by this method except when surface winds alter the launch angle of the rocket. Surface wind velocity corrections can be introduced to correct velocity and position information in the horizontal direction, but accurate wind correction data is difficult to obtain for all rockets. A special solar aspect sensor was designed to be used with a commercially available magnetic aspect sensor for rocket attitude determination. This attitude data allows the longitudinal acceleration to be broken more accurately into three vector components. A feasibility study of the aspect system was made using three Aerobee-150 rockets. A digital computer trajectory program was written to utilize aspect and acceleration data for trajectory analysis. It is evident that rocket attitude data is a useful supplement to the longitudinal acceleration data for trajectory determination. More accurate magnetic aspect data is necessary, however, to refine the longitudinal acceleration technique.
    • Telemetry for 250,000-G Gun Environment

      Finger, Daniel W.; Harry Diamond Laboratories (International Foundation for Telemetering, 1965-05)
      Techniques for packaging telemetry components and systems to withstand gun launch accelerations up to 250,000-g are discussed, and the necessary and sufficient conditions for survival are established. The principal requirements are that all voids be eliminated from the package and that encapsulating resins be adequately contained. The ultra-high-g projectiles used in hypervelocity research for which these telemeters were designed are briefly described. In addition, a brief description is given of high-g telemetry systems used in the gun-fired rockets and projectiles of project HARP.
    • An Advanced Integral Missile Evaluation System

      Mayo-Wells, Wilfrid J. (International Foundation for Telemetering, 1965-05)
    • A New Approach to Effective Digital Filter Design

      Duncan, P. H.; Douglas Aircraft Company (International Foundation for Telemetering, 1965-05)
      In this paper the effect of modifying digital filter weights derived on a least squares error basis through multiplication by certain weighting functions is investigated. It is shown that this approach amounts to adopting frequency resolution as a filter performance criterion, in a manner analogous to resolution in spectral estimates along the lines of Blackman and Tukey. Weight formulation using the method is very simple, and working transfer functions are easily estimated without computation. Simple, effective designs are presented for low, high and band-pass (or band-stop) filters of the "cosine" or in-phase type, for cosine "low low-pass" and "sampling" filters, and for "sine" or quadrature "sampling" filters, as well as differentiators.
    • Two-Way Telemetry for Hospital Use

      Johnston, E. B.; I.T.T. Federal Labs (International Foundation for Telemetering, 1965-05)
      A radio telemetry system for transmitting physiological data from a patient is used in a receiver complex to locate the patient. Methods of stimulating the patient for research or remedial control are discussed.
    • The Operational Pre-D for the Atlantis Missile Range

      Shollenberger, George D.; Defense Electronics, Inc. (International Foundation for Telemetering, 1965-05)
      This newly-developed receiving and predetection recording system currently being integrated into the Atlantic Missile Range should prove of considerable interest to the telemetry systems engineer. The system, designated TRKI-12, will become part of the familiar "Range Rehabilitation Program." The TRKI-12 is capable of handling up to twelve simultaneous telemetry signals of any known or projected telemetry format. Frequency-translation methods used enable recording and reproduction of high bit-rate PCM and other wide-bandwidth signals with minimum distortion. A wideband FM recording method gives true DC to 500-kc bandwidth recordings. The system incorporates a diversity reception and combining concept enabling optimum combination of telemetry data from diversity antenna systems without undesirable byproducts or need for special phase-correction. The description herein, which includes design constraints and limitations for a system of this type, should yield information of concern to the range user and should be especially useful in establishing efficient and economical range interfaces.
    • A Low Level Commutator with Field Effect Transistor Signal Gates

      Ely, William B.; General Devices, Inc. (International Foundation for Telemetering, 1965-05)
      A low level differential input commutator is described which uses field effect transistors for the signal gates. The commutator was built for airborne applications so that size, weight, and reliability were major considerations as well as electrical performance. Results are compared with commutators using other types of signal gates.
    • Application of a Telemetry System using DSB-AM Sub-Carriers

      Roche, A. O.; Dynatronics, Inc. (International Foundation for Telemetering, 1965-05)
      The advantages of the DSB-AM subcarrier for wideband telemetry requirements have been discussed in previous papers. The purpose of this paper is to consider the specific performance of an FM telemetry r-f link when modulated by a frequency multiplex of DSB subcarriers. The performance is evaluated by constructing an appropriate model of the subcarrier multiplex based on a predicted noise power spectrum at the r-f demodulator output. The model is used to specify the individual subcarrier amplitude values that constitute the baseband signal, which will modulate the FM transmitter. The carrier power required to produce a useful signal-to-noise ratio at the outputs of the individual subcarrier demodulators is considered in general. The relationship between the degree of transmitter deviation, receiver bandwidth and the carrier power is derived. The carrier power required for operation over typical test range distances is determined in terms of the appropriate variables. The performance of two specific examples is calculated to illustrate the use of the several formulae that are derived. The examples also serve to relate and compare the performance of the DSB system configurations to the more traditional applications. Finally, the advantage of using increased r-f bandwidth is discussed.
    • Conditioning and Recovery of Aircraft Position Signals Through an Existing Data Link

      Kashar, A.; Kearfott Division, General Precision Aerospace Group (International Foundation for Telemetering, 1965-05)
      A Signal Data Converter system records aircraft present po t on and altitude data on film and also displays this data in a ground shelter, allowing for real time surveillance by a ground observer. This is accomplished by adapting a unique digital data transmission system to an existing infrared video data link.
    • Matched Filter Systems in Rising Noise Spectrums

      Halpern, P.; Electro-Mechanical Research (International Foundation for Telemetering, 1965-05)
      It is common knowledge that the matched filters for signals in white noise have impulse responses whose time duration is exactly as long as that of the input signal. Nothing can be gained by extending the response of the matched filters to longer than one bit unless (1) the signal source is coded, or (2) the noise spectrum is rising or at least is other than white-Gaussian-ergodic. This paper discusses means of improving bit error rates without coding the source. There are essentially two ways of extending the integration time of the matched filters, each of which offers an improvement in signal-to-noise ratio. The first way is to extend the response directly to more than one bit but constrain the filter to give zero or some small pre-assigned intersymbol crosstalk. The second way is to build matched filters for multiple bits. Both techniques can be used simultaneously; i.e., matched filters can be constructed for bit patterns, and the responses can be extended to longer than the baud to which the filters are matched. Once again this extension is done under the constrain of zero or little crosstalk. In this paper, the matched filters for several examples are expanded in a rapidly converging series, each term of which is identifiable with a known network. For the cases where the shape of the noise is not known analytically, an experimental technique is given for determining sufficient statistics of the noise so that the optimum matched filters can be designed.
    • Receiver Noise Factor

      Hildner, Ernest G.; National Bureau of Standards (International Foundation for Telemetering, 1965-05)
      The Institute of Radio Engineers definition of receiver noise factor is reviewed and adopted for this paper. The definition’s implications are explored. CW-and dispersed-signal source measurement techniques are discussed and the mathematical base for each method is displayed. The quantities which must be measured in each method are pointed out with the respective advantages and disadvantages. It is concluded that the dispersed-signal source measurement technique is simpler than the CW-signal source techniques considered in this paper.
    • Five Basic Methods for the Generation of Binary Cyclic Codes

      Brothman, A.; Brothman, E. H.; Halpern, S. J.; Horowitz, L. M.; Miller, A. H. (International Foundation for Telemetering, 1965-05)
    • A Novel PMCM System for Geophysical Research

      Toney, P. A.; Walter, J. M.; Dynatronics, Inc. (International Foundation for Telemetering, 1965-05)
      The concepts leading to development of an inexpensive digital data acquisition system employing novel Pulse-Morse Code Modulation and providing accuracy comparable to that of PCM are discussed. The several system-level and circuit-level considerations permitting the complete elimination of separate signal conditioning equipment and receiving-site synchronization, recording and processing equipment are presented. Finally, there is a brief commentary on future applications of the device and suggestions for related work.
    • A Wideband UHF Transmitter for Space Applications

      Digiovanni, J. J.; Murphy, R. T.; Lockheed Missiles and Space Division (International Foundation for Telemetering, 1965-05)
      This paper describes the design and performance of a frequency-modulated 10watt S-band transmitter. Analogue frequency response is in excess of 7 Mc and digital signals at rates up to 10 megabits per second are transmitted satisfactorily. This extra wideband transmitter, ruggedized for space applications, utilizes a solid state exciter for signal generation, a traveling wave tube amplifier for power amplification, and a solid state traveling wave tube power supply that will withstand critical atmospheric pressures. A detailed analysis of rf bandwidth requirements and the state of the semiconductor art at the time of transmitter design resulted in the exciter taking the form of a 70 Mc voltage controlled oscillator whose output is amplified and converted to the S-band output frequency by means of broadband varactor harmonic generators. Production versions of this transmitter have consistently demonstrated satisfactory orbital operation. Laboratory data has indicated a minimum rf power output of 10 watts at base-plate temperatures ranging from -35° to +75° Centigrade. Baseband response is from 10 cycles to more than 7 Mc at ±6 Mc frequency deviation.
    • TELTRAC, A Telemetry Tracking Acquisition Aid System

      Knowlton, Orin H., Jr.; Canoga Electronics Corporation (International Foundation for Telemetering, 1965-05)
      TELTRAC, A Telemetry Tracking Acquisition Aid System, was manufactured by Canoga Electronics Corporation for the National Aeronautics and Space Administration to augment and update the Project Mercury systems for Project Gemini. In addition, many of the components of the TELTRAC System have been supplied to retrofit and upgrade the original Project Mercury systems. The features of the TELTRAC System that are new in comparison to previously existing Telemetry Trackers are the TELAR II Antenna and the Model 3403 Receiver, which employs both cross-correlation and phase-lock techniques. The TELTRAC System design criteria and a system error analysis, with particular emphasis on multipath errors, are discussed in this article. The detailed design of the TELTRAC System, as well as its subsystems, is also presented.
    • Design and Performance of a New S-Band Transmitter

      Swartley, Richard H.; Eitel-McCullough, Inc. (International Foundation for Telemetering, 1965-05)
      This paper describes a telemetry transmitter designed for the 2.2-2.3 Gc band. Design philosophy followed to achieve minimum size, wide deviation capability, high reliability and high efficiency are discussed in detail. The paper presents extensive measured data to indicate achievement of design goals set by IRIG 106-60 and ARTC-34. Construction details of the transmitter are illustrated.
    • Standards Re-evaluation for Wideband Magnetic Tape Recording

      Ratner, Vic A.; Defense Electronics, Inc. (International Foundation for Telemetering, 1965-05)
    • Frequency Spectrum of an FM/FM Signal

      Holt, J. C.; Douglas Aircraft Company (International Foundation for Telemetering, 1965-05)
      Several authors have attempted to derive a mathematical model that will describe the frequency spectrum of a FM/FM signal. However, to this author's knowledge, none of the mathematical models that have been published is valid when the carrier is modulated by more than one subcarrier. In this paper an expression for a FM/FM signal is derived that is valid when IRIG specifications are applied. Then this expression is manipulated into a form that will yield the frequency spectrum when the carrier is modulated by any number of subcarriers. Then an illustration of a two subcarrier frequency spectrum is presented.
    • Frequency Modulation Error Calculation

      Nyre, Donald L.; Douglas Aircraft Company (International Foundation for Telemetering, 1965-05)
      In a frequency modulation process, small amplitude sidebands near the deviation limits are sometimes distorted or lost. The problems and expense of preserving these lessor sidebands are often great, and spectrum space must be reserved for them. To date there appears to have been no clear statement of their importance in terms of data accuracy. This paper presents a numerical calculation of the errors accrued in a demodulated signal after truncation of the FM spectrum obtained with sinusoidal modulation. It is shown that the error increases for decreasing bandwidth. Error is evaluated for several bandwidths, and relationships to power outside the band are noted. Applications include specification of bandwidth for a given error in demodulated signal. The use of a limiter is assumed.