The annual output value of weak current cables in China has accounted for 30% of the total output value of the industry

In 2013, the annual output value of weak current cables in China exceeded 400 billion, accounting for 30%
of the total output value of the entire industry.
In 2013, the output value of China's wire and cable industry exceeded 1.
3 trillion, and the output value of the weak current cable industry exceeded one-third of the wire and cable industry, that is, the annual output value of weak current cable exceeded 400 billion
.

Weak current cables interact with video surveillance

The wire and cable industry is the "blood vessel" and "nerve" of the national economy, where there is electricity, there is kinetic energy, such as power grid, real estate, communications, automobiles, electronic appliances and other fields need wires and cables, especially in the security industry
.
In security products, whether it is video surveillance products, access control, building intercom products or anti-theft alarm products, their installation and use are inseparable from the connection of weak current cables, especially video surveillance products, due to a set of video surveillance equipment components more, it is more dependent on
cables.
At present, video surveillance products have a high degree of popularity in China, and it has become the main application field
of weak current cables.
It can be said that the development trend of weak current cables is largely determined by the development of
the video surveillance industry.
Rao Rangli, manager of the market development department of Foshan Lianxun Cable Industrial Co.
, Ltd.
, said that in the security industry, the development of weak current cables closely follows the pace of development in the field of video surveillance
.

On the other hand, the quality and selection of weak current cables will also have a great impact
on the effect of video surveillance products.
A set of installation, debugging, construction of a good video security system is selected are able to produce or process high-quality pictures of cameras, lenses, monitors, video recorders, but without a good transmission system, the final image seen on the monitor will not be satisfactory to reach the most ideal state
of the equipment.
According to the "barrel rule", the final image quality will depend on the worst link in the entire system; The worst part of this is often the data transmission system
.
The designers and installers of the system must choose the appropriate transmission method, high-quality transmission cables and equipment, and install according to professional standards according to actual needs in order to achieve the ideal transmission effect
.

Development status of weak current cables

At present, in the field of weak current cables, there are two cables with the most applications, namely coaxial cables and data cables
.
Tang Daibin made a detailed analysis of these two cables, pointing out that generally in a small-scale monitoring system, due to the close transmission distance, the use of coaxial cable to directly transmit monitoring images has little damage to the image quality, which can meet the actual requirements
.
However, according to the analysis of the characteristics of the coaxial cable itself, when the signal is transmitted within the coaxial cable, its attenuation is related
to the transmission distance and the frequency of the signal itself.
Generally speaking, the higher the signal frequency, the greater
the attenuation.
The bandwidth of the video signal is very large, reaching 5.
8MHz, and the color part of the image is modulated at the high end of the frequency, so that when the video signal is transmitted in the coaxial cable, not only the overall amplitude of the signal is attenuated, but also the attenuation of each frequency component varies greatly, especially the color part is the largest
attenuation.
Therefore, coaxial cable is only suitable for short-distance transmission of image signals, when the transmission distance reaches about 220 meters, the image quality will be significantly reduced, especially the color becomes dull, there is a sense of
distortion.

The use of data cables has been around for a long time, telephone transmission is twisted pair, in many industrial control systems and large interference places and long-distance transmission are used twisted pair, our widely used LAN today is also the use of twisted pair.

The reason why twisted pair is so widely used is because it has many advantages
such as strong anti-interference ability, long transmission distance, easy wiring, and low price.
Since the data line also has a large attenuation of the signal, the frequency of the signal cannot be too high when the transmission distance is long, and the high-speed signal such as Ethernet can only be limited to 110m
.
For video signals, the bandwidth reaches 6MHz, if it is transmitted directly in the data line, it will also be attenuated greatly, so the video signal must be amplified and compensated for long-distance transmission on the twisted pair, and the data line video transmission equipment is to complete this function
.
With the addition of a pair of twisted pair video transceiver devices, images can be transmitted to within
two kilometers.