• PROTOTYPE DUAL-BAND TRANSMITTER FOR AERONAUTICAL TELEMETRY APPLICATIONS

      Jensen, Michael A.; Jones, Charles H.; Brigham Young University; Edwards Air Force Base (International Foundation for Telemetering, 2002-10)
      Recent changes in spectrum availability as well as higher demands for spectrum have motivated the development of telemetry transmit systems capable of fully operating over both L and S telemetry bands. However, enabling operation within these two bands poses new problems in system design. This paper presents a prototype system capable of operating between 1.4 and 2.4 GHz, which supports continuous phase modulation (CPM) waveforms such as pulse code modulation (PCM), frequency modulation (FM), and shaped offset quadrature phase shift keying (SOQPSK). The system architecture is detailed, and the prototype performance is discussed.
    • SPACE-TIME CODING FOR WIRELESS COMMUNICATIONS

      Jensen, Michael A.; Rice, Michael D.; Brigham Young University (International Foundation for Telemetering, 2002-10)
      Signal fading and intersymbol interference created by multipath propagation have traditionally limited the throughput on wireless communications systems. However, recent research has demonstrated that by using multiple antennas on both transmit and receive ends of the link, the multipath channel can actually be exploited to achieve increased communication throughput over single-antenna systems. This paper provides an introductory description of such multi-antenna communications systems, focusing on basic explanations of how they achieve capacity gains. Computed and measured capacity results are used to demonstrate the potential of these systems.
    • TRANSMIT DIVERSITY SCHEME FOR DUAL-ANTENNA AERONAUTICAL TELEMETRY SYSTEMS

      Crummett, Ronald C.; Jensen, Michael A.; Rice, Michael D.; Brigham Young University (International Foundation for Telemetering, 2002-10)
      The use of two antennas on an aeronautical telemetry transmitter is a common practice for overcoming signal obstruction that can occur during air vehicle maneuvering. However, this practice also leads to interference nulls that can cause dramatic degradation in the average signal integrity. This paper discusses the application of a transmit diversity scheme capable of overcoming this interference problem. The development leads to symbol error probability expressions that can be applied to assess the performance of the scheme relative to that of traditional schemes. Representative computational examples demonstrate the potential of the method.