GE USM 36 Series Technical Reference And Operating Manual page 179

Distance-amplitude correction (DAC)
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.
USM 36 Issue 2 (12/2013)
5 Operation
5-103