Principle of shielded cable
The shielded wiring system originated from Europe. It is a metal shielding layer added to the outside of the ordinary unshielded wiring system. The reflection, absorption and skin effect of the metal shielding layer are used to prevent electromagnetic interference and electromagnetic radiation. The shielding system comprehensively utilizes The balance principle of twisted pair and the shielding effect of the shielding layer, so it has very good electromagnetic compatibility (EMC) characteristics.
Electromagnetic compatibility (EMC) means that electronic equipment or network systems have a certain ability to resist electromagnetic interference, and at the same time cannot generate excessive electromagnetic radiation. That is to say, it is required that the device or network system can work normally in a relatively harsh electromagnetic environment, and at the same time cannot radiate excessive electromagnetic waves to interfere with the normal operation of other surrounding devices and networks.