Crosstalk is a disturbance caused by the electric or magnetic fields of one telecommunication signal affecting a signal in an adjacent circuit.
The generation of wire crosstalk is mainly caused by electromagnetic coupling, and the main influencing factors include:
coupling length
Far end crosstalk (FEXT) is proportional to the coupling length, while near end crosstalk (NEXT) increases with length when the coupling length is less than the saturation length, and tends to stabilize when it exceeds the saturation length.
Line spacing
The smaller the line spacing, the greater the crosstalk. When the line spacing is ≥ 3 times the line width, crosstalk is significantly reduced.
Signal edge velocity
The faster the rising/falling edge of the signal (i.e., the higher the frequency), the greater the crosstalk.
Medium characteristics
The thickness and dielectric constant of insulating materials can affect the propagation characteristics of electric and magnetic fields, thereby affecting crosstalk.
Load Matching
Mismatched load impedance will reflect signal energy and increase near end crosstalk
