Terason t3000, Руководство пользователя

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Chapter 12 - System Safety and Maintenance Acoustic Output Indices
Terason t3000 / Echo Ultrasound System User Guide 275
The relative error in the spatial-peak derated temporal average intensity for
unscanned modes , defined as

SPTA.3-unsc.
, is approximately:
where the following is defined:
The relative error in estimating spatial-peak derated temporal average intensity for
scanned modes , defined as

SPTA.3-scan.
, is approximately:
where the following are defined:
The relative error in the peak derated rarefactional pressure , defined as

pr.3
, is
approximately:
The relative error in the Mechanical Index , defined as

MI
, is approximately:

lin
Relative error due to the effects of non-linearities in the
pressure waveform upon the hydrophone and integral
amplifier, estimated as 0% for this transducer set

PD
Relative error in estimate of pulse duration, estimated as 5%

prf
Relative error in prf estimation for operating condition giving
actual peak ISPTA.3-unsc., estimated as 1%

srf
Relative error in estimating srf (scan repetition frequency) for
operating condition giving actual peak I
SPTA.3-scan.
,
estimated as 1%

BOF
Relative error in estimating BOF (beam-overlap factor) for
operating conditions giving actual peak I
SPTA.3-scan.
,
estimated as 5%
Note: In accordance with Subsection 6.4.3 (Measurement of Precision of Peak
Rarefactional Pressure, p
r
) of the Standard for Real-Time Display of Thermal and
Mechanical Acoustic Output Indices on Diagnostic Ultrasound Equipment , a series
of ten independent measurements on the specified standard test transducer/driver
combination yielded a relative standard deviation of W of less than 1% for the
sample measurements.

SPTA.3-unsc.

2
SPPII.3
 
2
prf

1 2
/
11.3%
= + =

SPTA.3-scan.

2
SPII.3

2
srf

2
BOF
+ +
 
1 2
/
12.8%
= =

pr.3

1
2
---
 
 
SPPII.3
5.9%
= =