Security monitoring industry how to use transmission equipment is a very important part. Here we analyze the advantages and disadvantages of optical fiber, optical transceivers and other equipment, and guide users how to choose the right transmission equipment.
Monitoring system analysis
In general, a standard video surveillance system consists of five major components: a video acquisition system, a video transmission system, a video switching management system, a video display system, and a video recording system. The video acquisition system mainly completes the acquisition of the front-end image signal; the video transmission control system completes the transmission and control communication of the front-end image signal; the video switching management system completes the switching control and resource allocation of the image signal; the video display system completes the front-end image The output of the terminal equipment of the signal; the video recording system completes the long delay storage and playback of the front-end image signal.
In system engineering, good video transmission design is a very important part of the monitoring system. If a good system is built, the selected camera, lens, monitor, and video recorder are all high-index, high-cage-quality. However, if there is no good transmission system, the image that will eventually be seen on the monitor will not be able to make people. satisfaction. Because according to the "law of barrels", the final image quality will depend on the worst link in the entire system, and the worst link is often the transmission system. Therefore, the system design and installation personnel must select the appropriate transmission methods, high-quality transmission cables, special connectors and equipment according to actual needs, and install them according to professional standards in order to achieve the desired transmission effect.
Transmission system analysis
At present, there are two types of front-end cameras in the security surveillance industry: traditional analog cameras and network cameras. However, there are many media used to transmit image signals, mainly coaxial cables, twisted pairs, and optical fibers. The corresponding transmission devices are Coaxial video amplifiers, twisted pair video transmission equipment and optical transceivers. Let's analyze the performance advantages of the three most widely used transmission media in the current surveillance system.
Coaxial cable transmission
Coaxial cable is used earlier and is the most traditional video transmission method, but coaxial cable is only suitable for video transmission distance of several hundred meters, and its anti-interference ability is not strong, generally used for simulation in small factories or schools Camera monitoring, the use of coaxial cable transmission is relatively low cost.
Twisted pair transmission
Twisted pair transmission is far more than coaxial cable transmission distance, the maximum can reach 2400 meters, its cheap and easy access, anti-interference ability is not bad, using PoE power supply can also reduce the amount of integrated wiring tasks. However, due to the limitations of the twisted pair material itself, it is not resistant to aging and cannot be transported in places with relatively poor conditions, such as the field or chemical plants, and it can only transmit one image at a time, so it is not suitable for large and medium-sized monitoring and transmission at the same time. Distance is also limited. Twisted-pair transmission is more suitable for video surveillance of network cameras in environments where the short-distance distance and the camera position are relatively dispersed and not many or in close proximity but relatively concentrated, such as banks, hotel chains, supermarkets, or university campuses.
Optical fiber transmission
Using optical fiber to transmit image signals is the best way to solve long-distance transmission. Optical fiber transmission can reach tens or even more than 100 kilometers at the longest. It transfers video and control signals into optical signals for transmission in optical fibers. Its advantages are: long transmission distance, high speed, large bandwidth, low attenuation, and anti-jamming. The best performance, suitable for long-distance and large-scale video transmission, such as road intersection monitoring. The optical fiber transmission equipment mainly includes video optical transceivers and optical fiber transceivers. The video optical transceivers are mainly used in analog camera signal transmission. It has low signal loss, small noise and distortion, and high transmission quality, and is suitable for long-distance transmission. At present, the monitoring optical transceiver can transmit signals such as images, data, and voice without relay for 100 kilometers. Secondly, it has strong anti-interference ability. It is not affected by lightning and electromagnetic radiation. This is not available for coaxial cable transmission and twisted pair transmission. of.
Transmission bandwidth, theoretical up to 3 billion megahertz, large communication capacity, very suitable for video signal transmission. A video optical transceiver can simultaneously access multiple sets of analog video signals. It is suitable for multiplexing transmission. Currently, the monitoring optical transceiver can simultaneously transmit 128 channels of real-time uncompressed broadcast-level images on a single optical fiber, and the video optical transceiver can not only transmit video. Signals can also transmit audio signals. Fiber optic transceivers are suitable for network camera signal transmission. It also has the advantages of long distance, low loss and strong anti-interference ability of video optical transceivers. But compared to a single video transceiver, the volume of a single fiber transceiver is much smaller. The mini-sized fiber optic transceivers introduced by Keyi Corporation are only 88×50×25 (mm) in size, and can even be placed inside the camera housing. In the case of multiplexing, fiber switches are used, and PoE technology can also be used as front-end cameras. Power supply, reduce the amount of tasks of integrated wiring.
Project case analysis
Figure 1 shows a large factory monitoring system topology
It is divided into the plant's periphery monitoring and plant's internal workshop and warehouse monitoring. Because the plant area is relatively large, if the coaxial cable or twisted pair transmission is adopted, the transmission distance may not be reached. Therefore, only optical fiber transmission may be used. Because it is only for internal real-time monitoring and viewing, it does not need to purchase high-priced network cameras. It only needs to use analog cameras. Therefore, the Voptix series of digital video optical transceivers introduced by the company can meet this kind of requirements. Requirements, the series 1/2/4/8 video digital optical transceivers are non-network management and network management two types of products. Among them, for non-network management optical transceivers, the transmitter and receiver are all designed for miniaturization. They can be installed independently, and can be densely installed and centralized in a 19-inch 3U rack, and are tailor-made for the security monitoring market. Miniaturized 1- to 8-channel video, audio, data, Ethernet and other multi-service signal optical fiber transmission products, featuring high cost performance, strong environmental adaptability, stable operation, and easy installation.
Figure 2 shows a traffic intersection monitoring connection
A city needs to install cameras at each crossroads and collect data in real time to facilitate real-time viewing and monitoring at the city's traffic control center. It can promptly handle road congestion and traffic congestion problems; it can also monitor and record traffic violation vehicles. Provide effective evidence for subsequent processing. The use of the company's LS5300 series PoE fiber switches will not only solve the problem of long-distance traffic and large traffic (road monitoring generally uses high-definition cameras, and the flow of one camera will reach 10M or more), and will pass through the field. The long-distance PoE power supply technology, the maximum power supply distance can reach 150 meters, also solves the front camera power supply problem, reducing the number of integrated wiring processes, greatly reducing costs.
Conclusion
Because of the different conditions at each site of the project, there may be a large gap between the various construction processes that may be adopted and the materials and equipment required. This requires the vast number of engineering companies to choose products that are more suitable for their own products according to different environments.
Cement grinding aid is a kind of chemical additives can improve cement grinding effect and performance, can significantly improve the cement production, every period cement strength, were to improve its liquidity.Cement grinding aid can greatly reduce the grinding ball phenomenon formed in the process of electrostatic adsorption package, and can reduce the grinding of ultrafine particles in the process of coalescence trend again.Cement grinding aid can significantly improve the liquidity of cement and improve the mill grinding effect and efficiency of classifier choose powder, so as to reduce the energy consumption of grinding.Using grinding agent in the production of cement with a low compaction trend of coalescence, which benefits the loading and unloading of cement, and can reduce the phenomenon of wall hanging cement silo.As a kind of chemical additives, grinding agent can improve the cement particle distribution and hydration, so as to improve the early strength cement and later strength.
Cement Grinding Aids,Grinding Aid,Grinding Aid For Cement Mill,Grinding Aid For Cement Production
NINGBO LUCKY CHEMICAL INDUSTRY CO. LTD , https://www.nbluckychemical.com