Relationship between electrical impedance of a transducer and its electroacoustic behavior: Measurement without primary source

Abstract

Forward and backward waves in a reflective medium that loads a piezoelectric transducer under electrical impedance test are usually considered as a perturbation for the measurement. However, substantial information about the transducer and the medium sample properties can be obtained from such electrical impedance measurements. This information is equivalent to that obtained from a pulse/echo experiment and it is shown that echo wave forms are easily deduced from such measurements. Furthermore, in the case of an electrical impedance deduced from a noise measurement, it is shown that echo wave forms can be obtained from a passive method without primary external source.