Spectral Doppler Mode
7.1.2.9 Baseline
The PW spectrum baseline shift enlarges the velocity range in one direction. The displayed velocities
(cm/s, m/s) or frequencies (kHz) on the upper and lower edge of the screen (scale, white borderline)
mark the maximum velocity (maximum measuring range) .
The baseline can be shifted up in 8 steps or down in 8 steps.
Remarks:
Adjusting the baseline is possible in write- and read mode.
7.1.2.10 WMF
A “Wall Motion Filter” is used to eliminate Doppler “noise” that is caused by vessel wall or cardiac
wall motion and that 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 : 60Hz, 100Hz, 160Hz, 230Hz, 280Hz, 400Hz, 600Hz
Use the
[
WMF
]
flip switch to select the wall motion filter desired.
Switch up to increase, switch down to decrease the filter.
Remarks:
* The Wall Motion Filter is user-selectable but the actual cutoff frequencies vary 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.
* Changing the WMF is only possible in write mode. It has no function in read mode.
* The suitable WMF-filter is automatically calculated and adjusted when the PRF is changed.
7.1.2.11
Velocity Range (PRF)
The velocity range on display is governed by the pulse repetition frequency (PRF).
The
[
PRF
]
control changes the displayed range. As the velocity range is increased by the
[
PRF
]
control, the PRF increases. As the display scale increases, the maximum Doppler shift
information that can be displayed without aliasing increases, too.
Use the
[
PRF
]
flip switch to adjust the velocity range desired.
Switch up for increasing the PRF, switch down to decrease the PRF.
Depending on the SV gate depth, the possible maximum sampling frequency will be automatically
adapted.
When exceeding this maximum by further increasing the PRF, the HPRF mode is switched on.
Voluson
®
730Pro - Basic User Manual
7-8
105831 Rev. 0
Summary of Contents for Voluson 730Pro
Page 1: ... B BA AS SI IC C U US SE ER R M MA AN NU UA AL L GE Medical Systems Kretztechnik GmbH Co OHG ...
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Page 23: ...General 1 General 1 2 Voluson 730Pro Basic User Manual 105831 Rev 0 1 1 ...
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Page 446: ...Connections 21 2 1 Main Module Voluson 730Pro Basic User Manual 21 4 105831 Rev 0 ...