• BUBBLE MEMORY INSTRUMENTATION PACKAGE REPLACES DATA LINK IN PARACHUTE TEST SYSTEM AT NWC

      Rieger, James L.; Naval Weapons Center (International Foundation for Telemetering, 1982-09)
      A bubble-memory recorder for data taken from a parachute-measurement system is used to replace UHF telemetry using FM subcarriers. Significant savings in manpower for the test results, along with greater data quality and simpler, more repeatable data playback. New devices and a ground-based playback decommutator provide greater utility and normally end the requirement for a ground station.
    • INVESTIGATION OF FOUR-LEVEL PCM/FM FOR SPECTRUM CONSERVATION

      Cox, Timothy F.; Nichols, Myron H.; Naval Weapons Center (International Foundation for Telemetering, 1982-09)
      Four-level PCM/FM is investigated for reduced spectrum occupancy relative to binary PCM/FM. The spectrum occupancy can be reduced to 65% of binary PCM/FM at a carrier power cost of 4dB, to 58% at a carrier power cost of 7.6dB and to 50% at a carrier power cost of 10.2dB. This performance was achieved using a range type telemetry receiver. Spectra, waveforms, circuit details and BER characteristics are given.