Interference parameter

Parameters for interference variables are:

  • Rise time: as a measurement of the duration of the interference

  • Rate of change du/dt, di/dt: as a measurement of the intensity of the interference

  • Peak value: as a measurement of the energy of the interference

Causes of effective interference

NOTE: Causes of effective interference are exclusively amplitude variations in electrical parameters per time unit. The duration of the interference is identical to the duration of the change in the source of interference.

Frequency influence

The frequency spectrum of a disturbance variable is important because the inductive resistance and the capacitive resistance on a conductor depend on the frequency. The higher the frequency of the interference, the higher the interfering signal. Frequent interference signals cause a voltage drop on the inductive resistance of conductors which shows up as interference voltage. This causes a carrier flow on the line capacity that shows up as interference current.

Frequency spectrum of an interference pulse

To simplify matters, an interference pulse can be considered as a rectangular pulse form. This can be calculated as a sum of sinus functions. To recreate this pulse more precisely, i.e. the more slope that is defined for a pulse edge, the more frequent the required voltages must be.