With the development of image sensor technology, low-cost high-pixel sensors are increasingly used in security surveillance cameras, thus 720P, 1080P HD video camera is no longer unattainable luxury. With the development of digital technology, one million HD monitoring system has matured, it has developed to monitor the whole industry has played a great role, and HD monitoring system has become an inevitable trend. However, the current extensive use of high-definition products are based on network transmission technology, direct transmission in the HD era is almost extinct. But still it based on TCP / IP protocol network model, and such systems and the need to address the transmission delay, network congestion, support and maintenance of large problems. Because the network transport protocol is sent to the file system and developed, a small amount of data, real-time demanding, but the terminal device (computer) requirements, transmission and attach many conditions, resulting in the current network camera applications The actual situation. Thus, high-definition video signal transmission problems, then jammed his neck direct transmission of high-definition applications.
Video surveillance systems require the scene of the image signal is transmitted to the rear end of the control system, which covers a transmission distance of tens of meters to a few kilometers to a few hundred meters to a maximum transmission distance. The many features and data transmission technology is frequency-dependent, because the electrical signals transmitted on the signal line, and the frequency of the signal will be relevant, the higher the frequency, the faster the decay, the shorter the transmission distance; and signal information carried and and frequency, the greater the amount of information needed for the wider band, and the cost of transport is also more expensive. Therefore, look for a match with the actual application of technology to meet the costs as low as possible for the application to monitor the transmission mode is particularly critical.
Due to limitations transmission technology, making HD application has been greatly restricted, technology development need to find an efficient transport mode that reduces the original non-compressed video signal transmitted to the terminal, with the back-end video card or embedded DVR compression process, effectiveness, cost, stability, ease of construction and all standard definition analog video coaxial cable transmission system the same. Only in this way can poke HD clouds, get a lot of practical application.
Is well known, is a high quality coaxial cable transmission line, which can be used over a wide frequency band with low loss of electrical signal transmission, which is particularly suitable for transferring video signals. Coaxial cable + power cable is the most widely used video transmission medium, generally used for short-distance transmission of video signals. Electrical characteristics of coaxial cable makes it ideal for transferring video cameras to monitor the entire signal (CCTV cable video signal is generated by a very wide distribution of low-frequency signal and high frequency signal component). When transmitting low-frequency signals (20Hz to several thousand Hz), you can use almost any type of wire. But to be transmitted in a frequency range between 20Hz to 6MHz video signal, but does not want any attenuation, we need to use special coaxial cable. Thus, the coaxial cable is a high quality video signal transmission line video monitoring system is normally used.