| angular measure of a transducer beam|
Note 1 to entry: The beamwidth is typically measured in the transducer far field.
Note 2 to entry: The beamwidth can be quantified by either the half-angle or full angle.
Note 3 to entry: The beamwidth can be described at any one of the following points relative to the maximum: −3 dB, −6 dB, or −10 dB. However, it is imperative that whichever metric is used to calculate beamwidth, the relative level that defines that angle shall be stated with that beamwidth.
Note 4 to entry: The beamwidth is typically measured relative to the maximum response angle, rather than the principal axis of the housing or mounting points of the transducer.
Note 5: The beamwidth is generally dependent on acoustic frequency.