Countermeasures for Crosstalk

Crosstalk noise is induced by capacitive or inductive coupling between two adjacent transmission lines that run in parallel (called an aggressor and a victim). Regarding crosstalk, care should be exercised as to rapidly rising or falling signals. When such a signal travels through a transmission line, crosstalk noise is induced in an adjacent line (victim) and propagates in both directions: in the same direction as for the aggressor signal and in the direction opposite to it.
Since the speed of crosstalk propagation is equal to that of the aggressor signal, the crosstalk noise that travels in the same direction as the aggressor signal (called far-end crosstalk) appears as pulse-like noise.
On the other hand, the crosstalk noise that travels in the opposite direction (called near-end crosstalk) maintains a constant level while the aggressor signal propagates along the line.
Crosstalk noise also propagates along the aggressor line and then returns to the victim line.
Generally, you can prevent crosstalk as follows.

The below figure shows a typical level of crosstalk noise traveling along 30-cm traces.
This example shows near-end crosstalk. When the near end of the victim trace is the receiving end, it is susceptible to the effect of crosstalk.