Crosstalk between two terminated lines (R_{T}=∞,R_{S}= Z_{0})
An active line1 and a passive line2 are terminated by R_{S} at near end, and are open at far end.
The voltages at both ends of active line are:
The voltages at both ends of passive line are:
where
An example waveform for a rising step input v_{01}(t) with rise time tr=τ/2:
The pulse induced on passive line is called backward crosstalk or nearend crosstalk (NEXT). Focusing on the first wave (n=1), the voltage on passive line is:
where ξ is the crosstalk coefficient and r_{s} is the normalized source resistance:
The amplitude of backward crosstalk saturates at the line lengh:

In the case of a parallel data transmission or a source synchronous clocking, transmission lines are identical. We will calculate the crosstalk between two identical lines.
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The voltages of line1,2 will be derived from the voltages of even and odd mode. (→Multiple reflection in terminated coupledlines)
where
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For simplicity, we assume the conditions below:
(1) The farend impedance is HiZ: R_{T}=∞ i.e. Γ_{T+}=Γ_{T}_{−}=1
(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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We will compute an waveform using these equations. For convenience, we express the reflection coefficients
with the crosstalk coefficient ξ and the normalized resistance r_{S}:
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:
The pulse induced on passive line is called backward crosstalk or nearend crosstalk (NEXT).
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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 identities
, 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:
Note that the amplitude v_{2}(l,t) is twice as large as v_{2}(0,t) because of the total reflection (Γ_{T+}=Γ_{T}_{−}=1).
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Noting Γ<1, the amplitude attenuates exponentially with time. Then we will focus on the first wave (n=1) 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.
Especially, when the source resistance matches the characteristic impedance:
, the first wave on passive line is:
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If the propagation time 2τ is smaller than the rising time tr, the amplitude of crosstalk becomes small.
Conversely, the amplitude of backward crosstalk saturates at the line length: