• 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.
    • The Upper Bounds of the Confidence Intervals of Bit Error Probabilities Based on a Markov Chain Bit Error Model

      Mizuki, M.; Vandenberg Air Force Base (International Foundation for Telemetering, 1970-10)
      Confidence intervals for the bit error probability of an actual PCM telemetry data can be determined based on the analysis of received redundant bits. The procedure usually requires the assumption of independence of bit errors. However, bit errors may occur in clusters under various conditions of multipath, injection of nonthermal noise of long duration, and bit jitters. As a representation of bit errors in clusters, a Markov chain model is introduced. Some results on the confidence interval of bit error probability are obtained as functions of a Markovian parameter, which designates the degree of departure from the binomial model. The computations are quite laborious compared to the case of the binomial model. This paper gives step-by-step instructions for computing the probabilities that r error bits occur among mn received bits which can then be used for the derivation of the confidence interval.
    • 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.
    • VHF/UHF Antenna Calibration Using Radio Stars

      Taylor, Ralph E.; Stocklin, Frank J.; Goddard Space Flight Center (International Foundation for Telemetering, 1970-10)
      This paper describes a stellar calibration technique, using radio stars, that determines receiving system noise temperature, or antenna gain, at frequencies below 500 MHz. The overall system noise temperature is referenced to radio star flux densities known within several tenths of a decibel. An independent determination of antenna gain must be made before computing system noise temperature and several methods are suggested. The preferred method uses celestial and receiving system parameters to compute gain; whereas a less desirable method requires an accurately known output level from a standard signal generator. Field test data, obtained at 136 MHz and 400 MHz in the NASA space tracking and data acquisition network (STADAN), demonstrates that antenna gain and system noise temperature can be determined with an accuracy of 1 db. The radio stars Cassiopeia A and Cygnus A were used to calibrate 40-ft. diameter paraboloidal antennas, at 136 MHz and 400 MHz, and phase array antennas at 136 MHz. The radio star calibration technique, described herein, makes possible accurate station-to-station performance comparisons since a common farfield signal source is observed. This technique is also suitable for calibrating telemetry antennas operating in the IRIG 216-260 MHz frequency band.
    • Video Bandwidth, if Bandwidth and Peak Deviation in Notch Noise Testing

      Little, K. G.; Astro Communication Laboratory (International Foundation for Telemetering, 1970-10)
      This paper presents guidelines for conducting notch noise testing of telemetry transmitter-receiver systems. An understanding of the type of FM-FM modulation format which random white noise accurately simulates leads to certain convenient relations between spectral power density, video bandwidth, peak deviation and IF bandwidth. Notch noise measurements were made on video noise in a video limiter to determine the dynamic range required of a system which transmits random white noise faithfully. These measurements were of significant importance because they show that a great deal of excess IF bandwidth is required to transmit random noise spectra. Specifically, it was found that to achieve a 50 db notch noise measurement the system dynamic range may be as much as 10 times greater than the RMS value of the composite signals.