•
The Wall Motion Filter is user-selectable but the actual cutoff frequencies vary depending
on the [PRF] control setting.
•
The WMF-filter is calculated automatically and adjusted when the PRF is changed.
8.7.23.1 WMF for PW
A Wall Motion Filter is used to eliminate Doppler “noise” that is caused by vessel wall or
cardiac wall motion which is low in frequency but high in intensity. Use a wall filter that is high
enough to remove the audible thumping of the cardiac walls, but that is sensitive enough to
retain grayscale spectral information near the base line. The WMF control is used to change
the wall motion filter. The settings are: 70Hz, 120Hz, 155Hz, 190Hz, 230Hz, 300Hz and
500Hz.
Use the [WMF] control to select the wall motion filter desired. Press up to increase; press
down to decrease the filter.
Remarks:
•
The Wall Motion Filter is user-selectable but the actual cutoff frequency varies depending
on the [PRF] control setting. The lowest wall motion filter cutoff frequencies cannot be
used with the higher velocity range (PRF) setting. Likewise, the highest wall motion filter
cutoff frequencies cannot be used with lower velocity range (PRF) setting.
•
The suitable WMF-filter is automatically calculated and adjusted when the PRF is
changed.
Doppler Modes
8-42
Voluson® S6/S8 Basic User Manual
5433669-100 Revision 4
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