GE USM 36 Series Technical Reference And Operating Manual page 186

5 Operation
Change in the probe delay
Generally, a change in the probe delay automatically
also affects the shape of the sound field. This means
that a new recording of the reference echo would be the-
oretically required. However, minor changes in the de-
lay line, typically occurring due to the wear of the delay
line, have no noticeable effect on the programmed dis-
tance laws.
A T T E N T I O N
A recorded DAC curve no longer applies if
the probe delay changes to a larger extent,
e.g. caused by adding or removing a delay
line after a DAC curve has been recorded.
The same applies to immersion testing: The
DAC curve must be recorded after setting up
the final water delay line.
Failure to do so may lead to evaluation er-
rors.
5-110
Distance-amplitude curve according to JIS Z3060-2002 (JISDAC)
Automatic variation of the measuring point in TOF
mode
An echo amplitude evaluation is normally carried out at
the echo peak of the signal under examination because
this is the only way of ensuring that the displayed echo
amplitude and the sound path (projection distance,
depth position) always belong to the highest echo in the
gate.
N o t e
The USM 36 checks the measuring point set-
ting in TOF mode before processing any ref-
erence amplitudes. If PEAK is not set as
measuring point, the instrument will automat-
ically switch to PEAK. In this case, a note is
displayed at the bottom edge of the display
screen.
Issue 2 (12/2013) USM 36