Crosstalk between two terminated lines (R_{S}=R_{T}=Z_{g})
Active line1 and passive line2 are terminated by a common resistance R at both ends.
The voltages at both ends of active line are:
The voltages at both ends of passive line are:
where
Especially if R is equal to the geometric average of Z_{+} and Z_{−}:
then the voltages at both ends of active line are:
and the voltages at both ends of passive line are:
Therefore no crosstalk pulse induced at near end of active line and at far end of passive line. An example waveform for a rising step input v_{01}(t) with rise time tr=τ/2:
Focusing on the first wave (n=0), the voltage on passive line is:
where ξ is the crosstalk coefficient:

We will calculate the crosstalk between two identical lines, terminated by a common resistance R at both ends.
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The boundary conditions are:
(1) The termination resistances are equal at both ends : Γ_{S+}=Γ_{T+}=Γ_{+ , }Γ_{S}_{−}=Γ_{T}_{−}=Γ_{−}
(2) The propagation speeds are equal between even and odd mode : τ_{+}=τ_{−}=τ (TEM mode)
Then the voltages on line1,2 results in more simple form.
Active line:
Passive line:
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Here we assume the special condition that R is equal to the geometric average of Z_{+} and Z_{−}:
This means that the reflection coefficients Γ_{+} and Γ_{−} are equal in magnitude but opposite in sign:
Note that Γ_{+} can never be equal to Γ_{−} because Z_{−} is always larger than Z_{+} i.e. Γ_{+}<Γ_{−}.
Substituting Γ_{+}=−Γ_{−} into the equations above:
Active line:
Passive line:
Therefore no crosstalk pulse induced at near end of active line and at far end of passive line.
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We will compute an waveform using these equations. For convenience, we express the reflection coefficient
with the crosstalk coefficient ξ and the normalized resistance r:
Reminding that the R is chosen to equal to the geometric average of Z_{+} and Z_{−}:
Substituting this resistance, we obtain the reflection coefficients:
Assuming the input voltage v_{01}(t) is a rising step with rise time tr=τ/2, and r_{S}=1, ξ=0.4, the waveform is:
Note that no crosstalk pulse induced at near end of active line and at far end of passive line.
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For more intuitive understanding, we will simplify the equation above. We assume that the input voltage v_{01}(t) is a rising step.
Using the identity
, the voltages on line1,2 can be expressed in terms of the amplitude in nτ< t <mτ: v_{01}(tnτ)v_{01}(tmτ),
Active line:
Passive line:
or, explicitly
Active line:
Passive line:
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Noting Γ<1, the amplitude attenuates exponentially with time. Then we will focus on the first wave (n=0) on passive line:
Noting 0≦ξ＜1, its polarity is the same as the input voltage. And the amplitude is almost proportional to the crosstalk coefficient ξ.