Emi Prevention/Abatement - GE Vivid E80 Service Manual

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EMI prevention/abatement

EMI RULE
Be aware of Radio
Frequency sources
Ground the
Ultrasound system
Replace all screws,
Radio Frequency
gaskets, covers,
cores
Replace broken
Radio Frequency
gaskets
Do not place labels
where Radio
Frequency gaskets
touch metal
Use GE specified
harnesses and
peripherals
Take care with
cellular phones
Properly route
peripheral cables
2-8
Table 2-4: EMI prevention/abatement
DETAILS
• Keep the Ultrasound system at least 5 meters (15 feet)
away from other EMI sources.
• Special shielding may be required to eliminate
interference problems caused by high frequency, high
powered radio or video broadcast signals.
Poor grounding is the most likely reason an Ultrasound
system will have noisy images. Check grounding of the
power cord and power outlet.
• After you finish repairing or updating the Ultrasound
system, replace all covers and tighten all screws.
• Any cable with an external connection requires a magnet
wrap at each end.
• Install all covers. Loose or missing covers or Radio
Frequency gaskets allow radio frequencies to interfere
with the ultrasound signals.
If more than 20% or a pair of the fingers on an Radio
Frequency gasket are broken, replace the gasket. Do not turn
on the Ultrasound system until any loose metallic part is
removed.
Where applicable, never place a label where Radio
Frequency gaskets meet the Ultrasound system. Otherwise,
the gap created will permit Radio Frequency leakage. Or, if a
label has been found in such a position, move the label.
The interconnect cables are grounded and require ferrite
beads and other shielding. Also, cable length, material, and
routing are all important; do not change from what is
specified.
Cellular phones may transmit a 5 V/m signal; that could
cause image artifacts.
Where applicable, do not allow cables to lie across the top of
the Card Rack or hang out of the peripheral bays. Loop the
excess length for peripheral cables inside the peripheral
bays. Attach the monitor cables to the frame.
–
Vivid E80/E90/E95
GC091052 Rev. 3
Service Manual