Accession Number : ADA189442

Title :   Reciprocity Calibration of an Underwater Transducer by the Delta-Z Method.

Descriptive Note : Master's thesis,

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s) : Bedard, Raynald

PDF Url : ADA189442

Report Date : Dec 1987

Pagination or Media Count : 65

Abstract : A method for determining the free-field open-circuit voltage sensitivity of a reversible underwater electroacoustic transducer from the difference in its input electrical impedance when loaded by water and air was investigated theoretically and experimentally. An equation for the sensitivity was derived using reciprocal two-port network theory. The theory takes into account the diffraction due to the finite size of the transducer, its finite mechanical impedance, and its free-field radiation impedance in water. An experiment to test the predictions of the theory was performed using a 6 in diameter, hollow, piezoelectric ceramic spherical transducer. The results of the experiment agreed within several dB with standard comparison calibration over the frequency range for which both the electrical impedance and comparison calibration data are considered reliable. The calibration method described, which has been termed the Delta-Z Method, may be useful for in-situ monitoring of transducer sensitivity in installations which can be flooded and purged.

Descriptors :   *ELECTRICAL IMPEDANCE, *ELECTROACOUSTIC TRANSDUCERS, *MECHANICAL IMPEDANCE, *MONITORING, *UNDERWATER EQUIPMENT, CALIBRATION, CIRCUITS, COMPARISON, EQUATIONS, FREE FIELD, FREQUENCY, IMPEDANCE, INPUT, PREDICTIONS, RADIATION, REVERSIBLE, SENSITIVITY, SIZES(DIMENSIONS), THEORY, TRANSDUCERS, UNDERWATER, VOLTAGE, WATER

Subject Categories : Electrical and Electronic Equipment
      Submarine Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE