DEVELOPMENT OF AN INDEX OF REFRACTION SENSOR FOR ATMOSPHERIC SOUNDING.
BENDIX CORP SOUTHFIELD MICH RESEARCH LABS DIV
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This report describes the development of a capacitor -type of index of refraction sensor for atmospheric sounding. The basic concept employed was that the variations of permittivity of the sample air flowing through a sensing capacitor produce changes in a stable oscillators operating frequency. Since the change in permittivity is related by a simple square root function to the index of refraction, the percent change in oscillator frequency is directly proportional to the percent change in the index of refraction. A stable, crystal-controlled reference oscillator is included in the sensor to provide a difference frequency suitable for modulating a telemetry transmitter. The entire sensor was packaged for dropsonde applications. The report describes all the aspects of development, design, and laboratory and environmental tests. Sonde field test data, not reduced and analyzed at the time of writing, will be presented in a subsequent report. Author