Estimation of Echo Amplitude Through Interface Between Two Liquids of Different Sound Velocity

We have derived simple mathematical expressions for echo signal from wave equation for inhomogeneous medium. These relations have been applied successfully for the analysis of echo signal scattered by random medium, simple regular objects, and inclined plane. In these analysis it is assumed that an ultrasonic transducer and the scatterer lie in the same medium (one medium case).The transducer is often immersed in a different medium and the wave has passed through the interface twice during the measurement. In this paper the relation for echo signal is modified to the two media case. The amplitude of echo signal scattered by a simple object placed at the focal point of the transducer is estimated for the spherical and plane interface and compared that with experimentally obtained echo amplitude. With no adjustable parameters, rather good agreement between these two echo amplitude is observed.