GE M
EDICAL
S
YSTEMS
D
IRECTION
2392751-100, R
EVISION
3
V
IVID
™ 4 S
ERVICE
M
ANUAL
4-18
Section 4-4 - Image Testing: 2D/M/CFM/Doppler
4-4-1-11
CW Noise Test
4-4-2
7S Probe Image Quality Tests
4-4-2-1
2D Center Noise Test
NOTE:
This test should be performed in a dark room.
Table 4-28 CW Noise Test (3S)
Step
Task
Expected Result(s)
1
With a 3S probe in the air, select a Cardiac
preset and activate CW-Mode.
2
Set the Audio Gain to the minimal level at
which the audio noise is just visible.
Check that the Doppler audio and display noise are homogenous
and constant.
3
Move the cursor angle multiple times from one
half of the screen to the other.
Check that the noise level does not increase after the cursor angle
is changed.
Table 4-29 2D Noise Center Test (7S)
Step
Task
Expected Result(s)
1
With a 7S probe in the air, select a Pediatrics
preset.
2
Reduce the 2D Gain until the background
noise disappears.
3
Increase the Gain until “flashlight” noise is
displayed in the center of the screen, as
shown opposite, and write down the Gain
value.
4
Increase the Gain until the background noise
is displayed, and write down the Gain value.
Ensure that the Gain difference is not higher than 2.
