Carlon Structured Cable Management Systems Handbook - Low Res - Manual (Page 39)

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COUPLING PATHS
The coupling path is the route the EMI takes to get
from the source to the victim. Four important coupling
paths are:
Conducted Interference: The source and victim are
electrically connected by power, signal or ground wires.
Radiated Interference: The source generates elec-
tromagnetic waves (usually radio waves) which travel
through space and affect the victim. Noisy, powerful
electronic sources can be strong generators of elec-
tronic interference.
Inductive Interference: The wiring of the source and
the victim are close enough together to create coupling
due to mutual inductance. Inductive interference is
often associated with overlapping loops of wire.
Capacitive Interference: The wiring of the source
and the victim are close enough together to create
coupling due to mutual capacitance. Capacitive inter-
ference is often associated with wires or metal surfaces
which are very close, say, less than an inch apart.
EMI TROUBLESHOOTING AND FIXES
At this point in EMI problem solving, have a good idea
of where the noise is coming from (source), which
piece of equipment is being affected (victim), and
what path the noise is traveling to get from source to
victim. Now the job is to do something to reduce or
eliminate the problem. Trying some of the different
approaches listed below and testing the results is a
straightforward method of troubleshooting. Trained
technicians can use more advanced troubleshooting
methods which require special instruments. This may
be necessary for particularly troublesome situations.
As is usually the case, it is best to eliminate problems
at the source.
The easiest thing to do is to eliminate the source itself.
Is it still really required or desired? Can the source be
moved farther away, or transferred to a different,
separate circuit? Does the source need to be repaired,
replaced or fitted with design improvements or
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