Echo sounding technique

摘要

An ultrasonic echo sounding technique for reducing unwanted echoes from reflectors outside the focal line of a focused ultrasonic field is disclosed. In this technique at least two pulse-defined ultrasonic waves are successively transmitted. The amplitudes of the said waves are functions of an angle phi which is generated about the axis of the source of ultrasound. Echoes from the reflected waves are received from reflectors both on and outside the focal line and multiplied by an amplitude factor which is a function of the above mentioned angle phi . Echo signals associated with echoes having the same transit time are then added together.