Problems related to shielding systems in Integrated Wiring
In the Integrated Wiring System, unshielded and unshielded systems are widely used. The shielding system comprehensively utilizes the balanced principle of twisted pair wires and the shielding effect of the shielding layer. It has good electromagnetic compatibility and can prevent electromagnetic interference and electromagnetic radiation.
The advantages of shielded cabling can help the rapid development of the Internet. Many large data centers use shielded cabling systems. Therefore, the use of shielded cabling systems is one of the main trends in future integrated cabling. There are still many questions about blocking the system.
1. What is EMC?
EMC is electromagnetic compatibility. It refers to the ability of electronic devices or network systems to resist electromagnetic interference and prevent excessive electromagnetic radiation. That is to say, the device or network system is required to work normally in a harsh electromagnetic environment, and there are electromagnetic waves that do not allow excessive radiation to interfere with the normal operation of other equipment and networks.
2. How to measure performance differences between shielded and unshielded systems?
The advantage of the FTP cable shielding system is to provide better EMC performance than the UTP cable, which is based on isolating the system from the external electromagnetic environment. Because the external electromagnetic environment will affect the data transmission of the entire wiring system. So far, there are no performance indicators or test methods to express or compare EMC performance.
3. The UTP cable is an ideal balanced transmission system. Why do FTP cables need to be used?
The UTP cable achieves EMC performance through a twisted pair of core wires, which means EMI is first received by the UTP cable and then offset. However, as the frequency increases, the EMC performance of UTP will decrease. After measurement, it is found that the cable twisted pair can only meet the EMC performance of up to 30 MHz, and there is nothing to do with higher electromagnetic interference twisted pair. So far, most actual network applications work at a frequency lower than 30 MHz.
The ideal balanced transmission system does not actually exist. The balanced characteristics of UTP cables are not only dependent on the quality of the components, but are affected by the surrounding environment. This is because the metal around UTP, concealed "Ground", pulling, bending, and other conditions will undermine its balanced characteristics, thus reducing EMC performance.
4. What is the principle of FTP cable shielding?
Different from the balanced offset principle of twisted pair wires, the FTP cable adds one or two layers of aluminum foil to the outer of four pairs of twisted pair wires, and uses the reflection, absorption, and skin effect of metal on electromagnetic waves, it effectively prevents external electromagnetic interference from entering the cable, and also prevents internal signal radiation from interfering with the work of other devices.