The former is directly proportional to the signal frequency, the capacitance unbalance and the characteristic impedance of the lines. The magnetic field component is proportional to the signal frequency and the mutual inductance coupling between the two circuits and inversely proportional to the characteristic impedance of the lines. The total crosstalk is the vector sum of these two components. There is a limit to the effectiveness of twisting in reducing crosstalk between adjacent circuits. Experiments have shown that beyond 30 MHz, twisting is ineffective in reducing crosstalk.
Crosstalk is most significant at the transmitter end.
Near End crosstalk is generally independent of length. At higher frequencies, Far End crosstalk becomes significant. Far End Crosstalk increases with length and frequency. When more than one circuit is involved in simultaneous signal transmission, power sum crosstalk becomes important. Power Sum crosstalk refers to the total crosstalk generated by adjacent circuits affecting one of the circuits, as a result of signals present on the adjacent pairs.