| 监控安防工程中常用的几种线缆介绍 |
| 添加时间：2017/12/26 16:14:14 浏览次数： |
| 监控安防工程中使用最广泛的几种线缆包括同轴电缆，双绞线，以及光纤。下面是这些常用线缆各自的使用方法和功能作用，以及它们之间的区别等方面的知识要点。 The most widely used cables, including coaxial cables, twisted pair lines, and optical fibers, are the most widely used in monitoring and controlling security projects. The following are the knowledge points of the use and function of these common cables, as well as the differences between them. 1、同轴电缆 1. Coaxial cable 同轴电缆，是由一层层的绝缘线包裹着中央铜导体的电缆线。它的特点是抗干扰能力好，传输数据稳定，价格也便宜，同样被广泛使用，如闭路电视线等。同轴细电缆线一般市场售价几元一米，不算太贵。同轴电缆用来和BNC头相连，市场上卖的同轴电缆线一般都是已和BNC头连接好了的成品，大家可直接选用。 A coaxial cable is a cable that is covered with a central copper conductor by a layer of insulation. It is characterized by its good anti-interference ability, stable transmission of data, and cheap prices, which are also widely used, such as closed-circuit television. The common market price of coaxial cable is a few yuan a meter, not too expensive. The coaxial cable is used to connect with the BNC head. The coaxial cable sold on the market is generally the finished product which has been connected with the BNC head, and we can choose the coaxial cable directly. 在工程实际中，为了延长传输距离，要使用同轴放大器。同轴放大器对视频信号具有一定的放大，并且还能通过均衡调整对不同频率成分分别进行不同大小的补偿，以使接收端输出的视频信号失真尽量小。但是，同轴放大器并不能无限制级联，一般在一个点到点系统中同轴放大器最多只能级联2到3个，否则无法保证视频传输质量，并且调整起来也很困难。因此，在监控系统中使用同轴电缆时，为了保证有较好的图象质量，一般将传输距离范围限制在400-500米左右。 In engineering practice, in order to extend the transmission distance, a coaxial amplifier is used. The coaxial amplifier amplifies the video signal, and it can compensate the different frequency components with different sizes through equalization adjustment, so that the video signal at the receiving end is distorted as little as possible. However, coaxial amplifiers can not be cascaded without constraints. Generally, a coaxial amplifier can only cascade 2 to 3 points in a point-to-point system, otherwise, the quality of video transmission can not be guaranteed, and the adjustment is also very difficult. Therefore, when using coaxial cable in the monitoring system, in order to ensure better image quality, the range of transmission distance is generally limited to about 400-500 meters. 另外，同轴电缆在监控系统中传输图象信号还存在着一些缺点： In addition, there are some shortcomings in the transmission of image signals in the monitoring system of the coaxial cable. 1）同轴电缆本身受气候变化影响大，图象质量受到一定影响； 1) the coaxial cable itself is affected by the climate change, and the image quality is affected. 2）同轴电缆较粗，在密集监控应用时布线不太方便； 2) the coaxial cable is coarser, and the wiring is not very convenient in intensive monitoring and application. 3）同轴电缆一般只能传视频信号，如果系统中需要同时传输控制数据、音频等信号时，则需要另外布线； 3) the coaxial cable can only transmit video signal. If the system needs to transmit the control data, audio and other signals at the same time, it needs other wiring. 4）同轴电缆抗干扰能力有限，无法应用于强干扰环境； 4) the coaxial cable has limited anti-interference ability and can not be applied to the strong interference environment. 5）同轴放大器还存在着调整困难的缺点。 5) the disadvantages of the coaxial amplifier are also difficult to adjust. 2、双绞线 2, twisted pair 双绞线常见的有3类线，5类线和超5类线、6类线，以及7类线。前者线径细而后者线径粗，型号如下： There are 3 kinds of lines, 5 types of lines and ultra 5 lines, 6 lines, and 7 lines. The former has a fine line diameter and the latter line diameter is coarse, and the model is as follows: 1）一类线：主要用于传输语音（一类标准主要用于八十年代初之前的电话线缆），不同于数据传输。 1) a class of lines: mainly used for transmission of voice (a class of standards mainly used for telephone cables before the beginning of the 80s), different from data transmission. 2）二类线：传输频率为1MHZ，用于语音传输和最高传输速率4Mbps的数据传输，常见于使用4MBPS规范令牌传递协议的旧的令牌网。 2) two kinds of lines: the transmission frequency is 1MHZ, the data transmission is used for voice transmission and the highest transmission rate 4Mbps, which is commonly used in the old token network using 4MBPS specification token passing protocol. 3）三类线：在ANSI和EIA/TIA568标准中指定的电缆，该电缆的传输频率16MHz，用于语音传输及最高传输速率为10Mbps的数据传输主要用于10BASE--T。 3) three kinds of lines: the cables specified in the ANSI and EIA/TIA568 standards, the transmission frequency 16MHz of the cable, the data transmission for voice transmission and the highest transmission rate of 10Mbps is mainly used for 10BASE--T. 4）四类线：该类电缆的传输频率为20MHz，用于语音传输和最高传输速率16Mbps的数据传输主要用于基于令牌的局域网和 10BASE-T/100BASE-T。 4) four kinds of lines: the transmission frequency of this kind of cable is 20MHz, and the data transmission for voice transmission and maximum transmission rate 16Mbps is mainly used for token based LAN and 10BASE-T/100BASE-T. 5）五类线：该类电缆增加了绕线密度，外套一种高质量的绝缘材料，传输率为100MHz，用于语音传输和最高传输速率为100Mbps的数据传输，主要用于100BASE-T和10BASE-T网络。这是最常用的以太网电缆。 5) five kinds of lines: this kind of cable has increased the winding density, and has a high quality insulation material. The transmission rate is 100MHz, which is used for voice transmission and data transmission with the highest transmission rate of 100Mbps, mainly used for 100BASE-T and 10BASE-T network. This is the most commonly used Ethernet cable. 6）超五类线：超5类具有衰减小，串扰少，并且具有更高的衰减与串扰的比值（ACR)和信噪比（Structural Return Loss)、更小的时延误差，性能得到很大提高。超5类线的最大传输速率为250Mbps。 6) over five kinds of lines: over 5 classes, with less attenuation, less crosstalk, and higher ratio of attenuation to crosstalk (ACR) and Structural Return Loss, and smaller delay error. The performance is greatly improved. The maximum transmission rate of the ultra 5 line is 250Mbps. 7）六类线：该类电缆的传输频率为1MHz～250MHz，六类布线系统在200MHz时综合衰减串扰比（PS-ACR）应该有较大的余量，它提供2倍于超五类的带宽。六类布线的传输性能远远高于超五类标准，最适用于传输速率高于1Gbps的应用。 7) six kinds of lines: the transmission frequency of this kind of cable is 1MHz to 250MHz, and the six class cabling system should have a larger margin when the 200MHz is at 200MHz, and it provides 2 times the bandwidth of the super five class. The transmission performance of the six types of cabling is far higher than that of the super five standard, which is most suitable for the application with the transmission rate higher than the 1Gbps. 六类与超五类的一个重要的不同点在于：改善了在串扰以及回波损耗方面的性能，对于新一代全双工的高速网络应用而言，优良的回波损耗性能是极重要的。六类标准中取消了基本链路模型，布线标准采用星形的拓扑结构，要求的布线距离为：永久链路的长度不能超过90m，信道长度不能超过100m。 An important difference between the six and the super five categories is that it improves the performance in crosstalk and return loss. For the new generation of full duplex high-speed network applications, excellent return loss performance is very important. In the six category, the basic link model is cancelled. The star topology is adopted in the wiring standard. The routing distance is as follows: the length of the permanent link can not exceed 90m, and the channel length can not exceed 100m. 8）超六类线：超六类线是六类线的改进版，同样是ANSI/EIA/TIA-568B.2和ISO 6类/E级标准中规定的一种非屏蔽双绞线电缆，主要应用于千兆位网络中。在传输频率方面与六类线一样，也是200～250 MHz，最大传输速度也可达到1 000 Mbps，只是在串扰、衰减和信噪比等方面有较大改善。 8) over six lines: over six lines is an improved version of the six class lines. It is also a kind of unshielded twisted pair cable specified in the 6 class /E level of ANSI/EIA/TIA-568B.2 and ISO, which is mainly used in gigabit network. In terms of transmission frequency, it is also 200~250 MHz, and the maximum transmission speed can reach 1000 Mbps, just like six kinds of lines. It only improves in crosstalk, attenuation and signal-to-noise ratio. 9）七类线：该线是ISO 7类/F级标准中最新的一种双绞线，它主要为了适应万兆位以太网技术的应用和发展。但它不再是一种非屏蔽双绞线了，而是一种屏蔽双绞线，所以它的传输频率至少可达500 MHz，是六类线和超六类线的2倍以上，传输速率可达10 Gbps。 9) seven types of lines: the line is the latest one of the ISO 7 class /F standard twisted pair lines, which is mainly used to adapt to the application and development of ten thousand megabit Ethernet technology. But it is no longer an unshielded twisted pair, but a shielded twisted pair, so its transmission frequency is at least 500 MHz, which is more than 2 times of the six class line and the super six class line, and the transmission rate can reach 10 Gbps. 事实上，双绞线的使用由来已久，电话传输使用的就是双绞线，在很多工业控制系统中和干扰较大的场所以及远距离传输中都使用了双绞线，我们今天广泛使用的局域网也是使用双绞线对。双绞线之所以使用如此广泛，是因为它具有抗干扰能力强、传输距离远、布线容易、价格低廉等许多优点。由于双绞线对信号也存在着较大的衰减，所以传输距离远时，信号的频率不能太高，而高速信 In fact, the use of twisted pair has a long history. Telephone transmission is twisted pair. Many twisted pair lines are used in many industrial control systems and larger interference places, as well as long-distance transmission. The twisted pair is widely used in today's LANs. The reason why the twisted pair is so widely used is that it has many advantages, such as strong anti-interference ability, long transmission distance, easy wiring, low price and so on. Because the twisted pair also has a large attenuation to the signal, so the transmission distance is far away, the frequency of the signal can not be too high, and high speed signal. |
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