Thus, twisting reduces the noise voltage in a differential mode transmission line in proportion to the number of twists in the line. The differential receiver operates on the difference between the input from the two legs of the twisted pair. If electrical noise is present, this will not be complemented by the receiver circuit. Thus no output voltage will be present at the receiver output as a result of the noise voltage. This is the basis of differential mode transmission.
Crosstalk is made up of an electric field component and a magnetic field component.
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.