B-K Medical Pro Focus 2202, User Manual

Page: 140 / 356

140 Chapter 9
Gain
You can adjust the gain of the Color mode image. The view must be scanning when
you do this.
To adjust Color mode gain:
•
Turn the
[
Color/Power Gain
]
dial.
or
•
Click Gain under Color on the left side of the screen and drag the slider (or
point at Gain and press
[
+/-
]
).
The current Color gain setting (a percentage) is displayed on the screen next to
Gain.
Range
You can vary the PRF (pulse repetition frequency) to select the range of Doppler
velocities (frequencies) that are color-coded and displayed. Restricting the range
allows you to see velocity differences (within the range) in more detail.
To adjust the velocity range:
•
Press
[
Scale
z
]
to step through the available ranges.
or
•
Click PRF under Color on the left side of the screen and select the value you
want (or point at PRF and press
[
+/-
]
).
The color bar is updated to correspond to the new range of velocities.
The current setting is displayed on the screen next to PRF.
Wall Filter
A wall filter is used to eliminate low-frequency artifacts such as Doppler shifts
arising from respiratory and cardiac motion or movement of blood vessel walls. The
wall filter cuts off all frequencies below the cutoff frequency. You can adjust the cut-
of frequency.
To set the cutoff frequency for the wall filter:
•
Click Wall Filter under Color on the left side of the screen and select the value
you want (or point at Wall Filter and press
[
+/-
]
).
or
•
Press
[
Filter
F
]
to step through the available values.
The current setting is displayed on the screen next to Wall Filter.