COFDM mobile wireless monitoring equipment adopts a series of advanced COFDM multi-carrier communication technologies, modulation and demodulation technologies, channel coding and decoding technologies, error control technologies, and can be moved at high speeds in combination with multimedia network transmission technologies such as MPE-2 digital image compression. Real-time and synchronous transmission of high-definition video, voice, and other broadband multimedia services in the environment. The mobile wireless monitoring equipment has significant advantages such as wide coverage, high sensitivity, good mobility, strong anti-interference and anti-fading ability, high transmission data rate, outstanding stability and reliability, and the like.
Therefore, the wireless monitoring device is applied in non-visible and blocked environments, and has excellent "diffraction" and "penetrating" capabilities that make it suitable for real-time transmission of wireless images in urban areas, suburbs, and buildings. Ordinary wireless monitoring devices must establish the wireless link channel under visual conditions (where there must be no blocking between sending and receiving points). Therefore, the environment is more constrained by the environment. It is necessary to examine the application environment in advance and select and test the sending and receiving points. The direction of the antenna, the erection of the height of the antenna, etc., are very large and cumbersome. It not only directly limits the transmission and reception of audio and video, but also reduces the reliability and work efficiency of the system.
COFDM wireless monitoring equipment has completely changed this situation. Because of its multi-carrier and other technical characteristics, COFDM equipment has the advantages of "non-line-of-sight" and "diffractive" transmission. This setting can have a high probability in environments such as urban areas, mountains, and buildings that cannot be visible or blocked. Achieve stable transmission of images without being affected by the environment or by distance. The system adopts omnidirectional, can set up the wireless transmission link in the shortest time, the collecting end and the receiving end can also move at will, not being limited by the direction, the system is simple, reliable, application is flexible.
However, the transmission distance of COFDM mobile wireless monitoring equipment will still be affected by external factors. What are the major factors affecting the transmission distance of mobile wireless monitoring equipment? Here's a brief introduction:
1. Influence of Building Interior: The modern building is basically completed by a reinforced concrete structure. A large number of steel bars are embedded in the wall, the density of the steel bars is large, the diameter is thick, and the iron gates are used. Since the metal has the function of absorbing electromagnetic signals, the indoor transmission distance has no obvious outdoor transmission distance.
Outdoor: Each customer uses a different area of the environment, and the height and density of the surrounding house will also affect the transmission distance. If the houses are separated by a long distance and the building is high, relatively speaking, a better transmission distance will be obtained.
2. Installation height Because the earth is a curved principle, when the signal is transmitted for several kilometers or several tens of kilometers, the ground drop between launching and receiving is several meters to tens of meters. If the signal transmitted from the transmitting end is not in the receiving range, the receiving end of the LianTechnology is either receiving the signal wirelessly or the received signal is weak. Therefore, when transmitting over long distances, the more open the place where the antenna is placed, and the higher the antenna mounting, the more favorable the signal transmission distance.
3, antenna gain Transmitter and receiver antenna gain is high, the transmission distance will be more distant. The CPFDM low-frequency omnidirectional antenna gain is up to 8dbi and the directional antenna gain is 11dbi. When the Leroy technology system equipment is configured, the transmitter selects different antennas according to different use requirements, such as: two omnidirectional antennas or one omnidirectional pair Directional antenna.
4, equipment power in the same transmission environment and conditions, equipment transmission power, transmission distance.
5, signal modulation mode Channel modulation when the bandwidth of a variety of options, 2/4/6/8 four bandwidth settings, the smaller the bandwidth, transmission distance advantage is more obvious. From a clear point of view, the smaller the bandwidth is, the more certain the video resolution is. In fact, it is not affected by most of Lean's video surveillance. It is only when high-standard video transmission such as broadcasting and television signal transmission is selected that the high-frequency width can transmit higher-quality pictures.
6, electromagnetic environment interference COFDM is low-frequency work, in some places there may be other devices with the same frequency, Levin technology due to the same frequency interference, transmission distance will be affected. When using COFDM wireless monitoring equipment to set up a wireless video transmission system, we try to install the receiving base station at a relatively high position, so that its coverage is greatly improved, and it can transmit farther distances in the case of blockage. Specifically how to choose COFDM wireless monitoring equipment, please call Shenzhen Leian science and technology staff, according to your site environment for you to customize your wireless video transmission solutions and wireless monitoring equipment.
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