• BENEFITS AND TECHNIQUES FOR INCREASED POWER EFFICIENCY IN MODERN TELEMETRY TRANSMITTERS

      Bozarth, Don; Horcher, Greg; L-3 Communications (International Foundation for Telemetering, 2007-10)
      With recent developments in telemetry transmitter technologies, significantly greater DC to RF power efficiencies can be achieved. These new high efficiency transmitter designs may impact overall system design trade-offs by reducing the system size and weight requirements for batteries, heat sinks, and cabling. Furthermore, these fully DC isolated, next generation ARTM Tier 0, I and II enabled devices offer unique options to the platform designer in EMI/EMC control and system design. Advanced manufacturing techniques coupled with adaptive microprocessor control promises enhanced functionality, improved performance and reduced unit costs. The paper presents the performance of a new, high efficiency, telemetry transmitter topology and the possible system benefits involved with the application of this advanced transmitter technology within modern and legacy telemetry platforms. Specific sub-assembly circuit design techniques will be discussed and compared with prior design approaches.
    • ENHANCING THE PCM/FM LINK - WITHOUT THE MATH

      Fewer, Colm; Wilmot, Sinbad; ACRA CONTROL INC (International Foundation for Telemetering, 2007-10)
      Since the 1970s PCM/FM has been the dominant modulation scheme used for RF telemetry. However more stringent spectrum availability as well as increasing data rates means that more advanced transmission methods are required to keep pace with industry demands. ARTM Tier-I and Tier-II are examples of how the PCM/FM link can be enhanced. However these techniques require a significant increase in the complexity of the receiver/detector for optimal recovery. This paper focuses on a quantitative approach to improving the rate and quality of data using existing PCM/FM links. In particular ACRA CONTROL and BAE SYSTEMS set themselves the goal of revisiting the pre-modulation filter, diversity combiner and bit-sync. By implementing programmable adaptive hardware, it was possible to explore the various tradeoffs offered by modifying pulse shapes and spectral occupancy, inclusion of forward error correction and smart source selection. This papers looks at the improvements achieved at each phase of the evaluation.