Functional checks
Vivid E80/E90/E95 – Service Manual 4-25
GC091052 Rev. 3
NOTE: Frequency and Frame rate settings may affect the Low
Velocity Reject.
• Adjust Power to obtain an acceptable image using the
lowest setting possible. This is particularly important in CW
mode, as the energy duty cycle is 100% (constant).
NOTE: The Doppler Power setting affects only Doppler operating
modes.
Adjust the following settings to further optimize the display of the
image.
• Use the Horizontal sweep to optimize the sweep speed.
• To view signal detail, adjust Scale to enlarge the vertical
spectral Doppler trace. Velocity range directly controls the
pulse repetition frequency, which is responsible for the
setting of the Nyquist limit (the ability to detect maximum
velocity without aliasing).
• Use Invert to reverse the vertical component of the spectral
Doppler area of the display.
• Use Quick angle and Angle correction to steer the
ultrasound beam to the blood flow to be measured (Not
typically required during cardiac studies).
• Adjust LPRF (PW Doppler mode only) to toggle between
high and low Pulse Repetition Frequency (PRF). When the
Doppler PRF is raised beyond a certain limit, more than one
Doppler gate is displayed on the screen.
• Press Auto on the Control panel to activate Automatic
Spectrum Optimization (ASO). ASO is used to automatically
adjust baseline and scale of the PW/CW spectrum to
optimize the spectral display. It will avoid the display of a
folded spectrum and stretch the spectrum vertically as large
as possible. ASO optimization is not continuous but
performed instantaneously each time Auto is pressed.
Tissue Velocity Imaging (TVI) Checks
Introduction
TVI calculates and color codes the velocities in tissue. The
tissue velocity information is acquired by sampling of tissue
Use all noise reduction controls with care. Excessive
application may obscure low level diagnostic information.
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