Coaxial cable standard coaxial cable working princ

2022-07-22
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The coaxial cable takes hard copper wire as the core and is wrapped with a layer of insulating material. This layer of insulating material is surrounded by closely woven mesh conductors, and a layer of protective material is covered outside the mesh

coaxial cable is also one of the most common transmission media in LAN. The pair of conductors used to transmit information is selected according to the structure that a cylindrical outer conductor is sleeved outside the inner conductor (a thin core), and the two conductors are isolated from each other with insulating materials. The center of the outer conductor and the central axis core are on the same axis, so it is called coaxial cable. The reason why coaxial cable is designed in this way is also to prevent external electromagnetic waves from interfering with the transmission of abnormal signals. Next, I will introduce the coaxial cable standard and the working principle of coaxial cable

coaxial cable standard

coaxial cable adopts gb/t14864-1993 national standard. Video coaxial cable is a cable composed of two coaxial and mutually insulated cylindrical metal conductors to form a basic unit (coaxial pair), and then a single or multiple coaxial pairs. Coaxial cable is divided into four layers from inside to outside: central copper wire, plastic insulator, mesh conductive layer and wire sheath. The central copper wire and the mesh conductive layer form a current loop. It is named for the coaxial relationship between the central copper wire and the reticular conductive layer

working principle of coaxial cable

coaxial cable is divided into four layers from inside to outside: central copper wire (single strand solid wire or multi strand stranded wire), plastic insulator, mesh conductive layer and wire sheath. The central copper wire and the mesh conductive layer form a current loop. It is named for the coaxial relationship between the central copper wire and the reticular conductive layer. Coaxial cables conduct alternating current rather than direct current, which means that the direction of current is reversed several times per second. If ordinary wires are used to transmit high-frequency current, this kind of wire will be equivalent to an antenna transmitting radio outward. This effect consumes the power of the signal and reduces the strength of the received signal. Coaxial cable is designed to solve this problem. The radio emitted by the central wire is isolated by the mesh conductive layer, which can control the emitted radio by grounding. There is also a problem with coaxial cable, that is, if a certain section of the cable is greatly squeezed or twisted, the distance between the central wire and the mesh conductive layer is not consistent, which will cause the internal radio waves to be reflected back to the signal transmission source. This effect reduces the acceptable signal power. In order to overcome this problem, a layer of plastic insulator is added between the central wire and the mesh conductive layer to ensure the consistent distance between them. This also causes the cable to be relatively rigid and not easy to bend

advantages and disadvantages of coaxial cable

the advantages of coaxial cable are that it can support high bandwidth communication on relatively long lines without repeaters, and its disadvantages are also obvious: first, it is large, and the diameter of the thin cable is 3/8 inch thick, which takes up a lot of space in the cable duct; Second, it cannot bear entanglement, pressure and serious bending, which will damage the cable structure and prevent the transmission of signals; Finally, the cost is high, and all these shortcomings can be overcome by twisted pair. Therefore, in the current LAN environment, it has been basically replaced by the Ethernet physical layer specification based on twisted pair

editor's summary: This is the introduction of the coaxial cable standard and the working principle of coaxial cable. I hope it will be helpful to you. If you want to know more about it, you can pay attention to the information

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