(XT) in the electronics industry refers to any
condition by which a signal transmitted on one
circuit or channel of a transmission system creates
an undesired effect in another circuit or channel.
Therefore crosstalk is also referred to as the
effect seen on a circuit from neighboring signals.
In integrated circuit design, crosstalk normally
refers to a signal affecting another nearby signal.
Usually the coupling is capacitive, and to the
nearest neighbor, but other forms of coupling
and effects on signal further away are sometimes
important, especially in analog designs.
are two types of crosstalk in a transmission:
Far-end crosstalk (FEXT) which is the noise a
channel hears from a neighboring channel. FEXT
is the noise on the opposite side of the circuit
or when reference this noise in relationship to
a connector it would be at the other end of the
The second type of crosstalk is Near-end crosstalk
(NEXT). NEXT is the effect a channel might experience
from a nearby channel on the same end of the circuit.
In relationship to connectors this would be on
the same side of the connector.
Many customer ask how we test for each
of these types of crosstalk?
We Inject a signal into a neighboring differential
pair (aggressor) and
listen to the effect it has on our focus differential
pair (victim). Our engineers then run this test
with each of the neighboring circuits and provide
the data. The data is to see how our focus signal
may be affected. In Summary, the test is to see
the effects the neighboring circuits have on a
certain circuit in the connector which is being
a rule of thumb, the crosstalk value is around
5%, If the value is larger for the crosstalk this
means the crosstalk is having a significant effect
on signal performance. Therefore engineers and
designers target crosstalk in the 5% range or
shielding of connectors and the plating has significant
influences on crosstalk and therefore these are
the tested carefully by our engineers. The plastic
housing material and design are analyzed as well
so Crosstalk has a minimal effect in regards to