This document – provides definitions for the transmitted field characteristics of focusing and nonfocusing transducers for applications in medical ultrasound; – UHODWHV WKHVH GHILQLWLRQV WR WKHRUHWLFDO GHVFULSWLRQV GHVLJQ DQG PHDVXUHPHQW RI WKH transmitted fields of focusing transducers; – gives measurement methods for obtaining defined field characteristics of focusing and nonfocusing transducers; – specifies beam axis alignment methods appropriate for focusing and nonfocusing transducers.