CoaxialCអាច ("coax" for short) has long been used to transmit data and video signals. It is one of the first media to support 10BASE2 and 10BASE5 Ethernet, which can achieve 10 Mb/s up to 185 meters or 500 meters, respectively. s transmission. The term "coaxial" means that the central conductor of the cអាច and its shield have the same axis or center point. Some coaxial cអាចs may have multiple shielding layers, such as a four-shielded coaxial cអាច, which contains two layers of shielding, and each layer of shielding is composed of aluminum foil wrapped with wire mesh. The shielding characteristics of coaxial cអាច make it have strong anti-electromagnetic interference ability and can transmit high-frequency signals over long distances.
Although we usually think that coaxial cអាច is only used in broadband video and cអាច television (CAទូរទស្សន៍) home applications, in the business enterprise environment, from closed circuit television (CCទូរទស្សន៍), audio and video to RF antennas, and even some network connections, you can find Its figure. Therefore, it is very necessary to understand this cអាច medium and how to test it.
There are many different types of coaxial cអាចs that support a wide range of professional applications, such as satellite communications, industrial, military, and marine applications. The three most common types of non-industrial Coaxial cអាចsគឺRG៦, RG11និងRG៥៩, ក្នុងចំនោមនោះRG៦ត្រូវបានប្រើជាទូទៅបំផុតCCទូរទស្សន៍ CអាចនិងCAទូរទស្សន៍ Cអាច in corporate environments. The center conductor of RG11 is thicker than RG៦, which means that its insertion loss is lower and the signal transmission distance is longer. However, thicker RG11 cអាចs are more costly and very difficult to bend, which makes them unsuitអាច for deployment in indoor applications, but more suitអាច for long-distance outdoor installations or straight backbone links. RG៥៩ is more flexible than RG៦, but its loss is higher. It is rarely used in other applications except for low-bandwidth, low-frequency analog video applications (rear-view cameras in automobiles) with short distances and limited wiring space.
សញ្ញាបញ្ជូនឌីជីថល 3 (DS3) ដែលត្រូវបានប្រើនៅក្នុងការិយាល័យកណ្តាល (ហៅម្យ៉ាងទៀតថា T3) សេវាបញ្ជូនក៏ប្រើផងដែរCoaxial cអាចsរួមទាំង ៧៥Ω 735 type and 734 type. The 735 type cអាច has a coverage distance of 69 meters, while the 734 type cអាច has a coverage distance of 137 meters. RG៦ cអាច can also be used to transmit DS3 signals, but the coverage distance is shorter.