Acoustic Measurement Precision And Uncertainty - FujiFilm SonoSite M-Turbo User Manual

Table 44: Acoustic Output Terms and Definitions (Continued)
Term Definition
d (z) Equivalent beam diameter as a function of axial distance z, and is equal to
eq

function of z in centimeters.
fc Center frequency in MHz.
Dim. of A Active aperture dimensions for the azimuthal (x) and elevational (y) planes in
aprt
centimeters.
PD Pulse duration (microseconds) associated with the transmit pattern giving
rise to the reported value of MI.
PRF Pulse repetition frequency associated with the transmit pattern giving rise to
the reported value of MI in Hertz.
p @PII Peak rarefactional pressure at the point where the free-field, spatial-peak
r max
pulse intensity integral is a maximum in Megapascals.
d @PII Equivalent beam diameter at the point where the free-field, spatial-peak
eq max
pulse intensity integral is a maximum in centimeters.
FL Focal length, or azimuthal (x) and elevational (y) lengths, if different
measured in centimeters.

Acoustic measurement precision and uncertainty

All table entries have been obtained at the same operating conditions that give rise to the
maximum index value in the first column of the table. Measurement precision and uncertainty
for power, pressure, intensity, and other quantities that are used to derive the values in the
acoustic output table are shown in the table below. In accordance with Section 6.4 of the Output
Display Standard, the following measurement precision and uncertainty values are
determined by making repeat measurements and stating the standard deviation as a
percentage.
     Wo      z    
, where I
4 I
TA
(z) is the temporal-average intensity as a
TA
Chapter 6: Safety 165