Media Degradation
In general, media is susceptible to degradation. The sources of the degradation can be internal or external. When signals degrade over distance, it is called attenuation. Three internal factors can cause attenuation:
- Resistance: Opposition to the flow of electrons in a wire
- Inductance: Opposition to the changes of electrical current in the wire
- Capacitance: Opposition to voltage changes in the wire
When these internal opposition forces are combined and measured, the measure is called impedance.
Each type of cabling has its own impedance rating, which is part of its specification.