GE Vivid 7 Service Manual page 315

GE H
EALTHCARE
D FC091194, R
IRECTION EVISION
4-3-9-3 Check Horizontal Sweep, Velocity Range, Baseline and Low Velocity Reject
Table 4-19
Step
1.
2.
3.
4.
11
Doppler Mode Controls Checks
Task
Adjust HORIZONTAL SWEEP
Adjust VELOCITY RANGE
Move BASELINE
Adjust Low Velocity Reject (LV REJ.)
Chapter 4 - Functional Checks
V
Expected Result(s)
Adjusts the horizontal refresh rate of the Doppler area
of the display.
Horizontal sweep is available in live and cine replay.
Enables the vertical scale of the Doppler spectrum and
the maximal detectable velocity to be modified.
Velocity range directly controls the pulse repetition
frequency, which is responsible for the setting of the
Nyquist limit (the ability to detect maximal velocity
without aliasing).
Enables the Doppler baseline to be shifted up and
down.
The default Doppler baseline is set at the center of the
vertical aspect of the Doppler display, dividing evenly
the flow toward and away from the probe.
By adjusting the baseline a larger portion of the analysis
is assigned to the flow direction present.
Baseline is available in live and cine replay.
Enables the low velocity portions of the spectrum to be
filtered, since the Doppler spectrum and audio may
contain strong wall-motion signals.
The amount of LV Rej. is indicated by the green vertical
bar at the right end of the baseline.
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IVID ERVICE ANUAL
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