
Operation Manual
4-28
Tips!
Important Information for Real Time Automatic Doppler Trace!
The Doppler spectrum trace and measurement results may not be accurate if: -
1. aliasing occurs because the PRF is too low compared to the speed of the region examined or the
spectrum is over-shifted to the baseline because the PRF is too high;
2. the peak is unclear or irregular, such as for the spectrum of veins;
3. meaningful identification of spectrum is difficult because the Doppler Gain Setting is too high or
too low;
4. attempting to read the Index Display during the transitional period immediately after relocating
the sample volume with the trackball;
5. major spectrum signals are cut off because the Doppler Wall Filter Setting is too high;
6. the peak trace suffers interference due to abnormal Doppler noise or Artifacts;
7. the heart rate is about 140 bpm or higher; or
8. Auto Calc is performed using inaccurate values.
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