In the wiring selection of the monitoring system, we cannot simply say whether to use twisted pair or coaxial cable. This needs to be decided based on our monitoring environment and monitoring distance requirements. When wiring, we need to consider multiple aspects and choose the optimal solution, so that we can not only reduce cost investment, but also achieve good monitoring effects.
In the wiring selection of the monitoring system, we cannot simply say whether to use twisted pair or coaxial cable. This needs to be decided based on our monitoring environment and monitoring distance requirements. When wiring, we need to consider multiple aspects and choose the optimal solution, so that we can not only reduce cost investment, but also achieve good monitoring effects.
Specifically:
Coaxial cable: It has the advantages of being cheaper and easier to lay (compared to optical fiber). Therefore, in small-scale monitoring systems, due to the short transmission distance, coaxial cables are used to directly transmit monitoring images. There is little damage to the image quality and it 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, the attenuation it suffers 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 6MHz, and the color part of the image is modulated at the high end of the frequency. In this way, when the video signal is transmitted within the coaxial cable, not only the overall amplitude of the signal is attenuated, but also the attenuation of each frequency component is very different. , especially the color part attenuates the most. Therefore, coaxial cables are only suitable for transmitting image signals at short distances. When the transmission distance reaches about 200 meters, the image quality will decrease significantly, especially the colors will become dim and distorted. However, coaxial cable is relatively low-cost, so it is suitable for analog camera monitoring in small factories or schools.
Twisted pair: Compared with coaxial cable, the transmission distance of twisted pair is much longer, up to 2400 meters. It is cheap, easy to access, and has good anti-interference ability. PoE power supply can also reduce the workload of comprehensive wiring. . However, the twisted pair material is weak in anti-aging and can only transmit one image at a time. Therefore, it is more suitable for video surveillance of network cameras in environments with short to medium distances and where the camera points are not scattered relatively much or the points are close but concentrated, such as banks, hotel chains, supermarkets, or university campuses.
In addition, in the wiring selection of the monitoring system, optical fiber can also be selected according to specific circumstances. The advantages of optical fiber transmission are: long transmission distance, high speed, large bandwidth, small attenuation, and best anti-interference performance. It is suitable for long-distance and large-scale video transmission, such as road intersection monitoring. The longest distance can even reach tens of hundreds of kilometers. It converts video and control signals into optical signals and transmits them in optical fibers.
The equipment that uses optical fiber transmission is mainly video optical transceiver and optical fiber transceiver. Video optical transceiver is mainly used in signal transmission of analog cameras. It has small signal loss, small noise and distortion, high transmission quality, and is suitable for long-distance transmission. Optical fiber transceivers are suitable for signal transmission of network cameras. They also have the advantages of long transmission distance, low loss, and strong anti-interference ability of video optical transceivers. Using fiber optic switches, PoE technology can also be used to power front-end cameras, reducing the workload of integrated wiring. Therefore, optical fiber is the best way to solve long-distance transmission.
However, the use of optical fibers and optical transceivers requires certain professional knowledge and special equipment, which brings certain difficulties to engineering construction and user use. In addition, for short-distance, small-scale monitoring systems, the use of optical fiber transmission is not economical enough.