The monitor has a grainy disturbance that does not overwhelm the normal image when it is light, and it can't be viewed (and even destroy synchronization) when it is severe. The cause of this kind of failure phenomenon is more and more complicated. There are roughly the following reasons:
1. The quality of the video transmission line is not good, especially the shielding performance is poor (the shielding network is not a good quality copper network, or the shielding network is too thin to be used for shielding). At the same time, the line resistance of such video lines is too large, which causes the signal to have a large attenuation is also aggravating the cause of the failure. In addition, the characteristic impedance of such a video line is not 75 Ω and one of the causes of the malfunction is that the parameter is out of specification. Since the above-mentioned interference phenomenon is not necessarily a fault caused by a defective video line, the reason for this failure should be accurate and careful when judging. Only from the point of view of the video line can be considered when other possibilities are excluded. If it is really a cable quality problem, the best way is of course to replace all of these cables and replace them with cables that meet the requirements. This is the best way to completely solve the problem.
2, due to the power supply system is not "clean" and caused. The power source referred to here is not "clean" and means that an interference signal is superimposed on a normal power source (a 50-cycle sine wave). This type of interference signal on the power supply mostly comes from devices that use thyristors in the power grid. In particular, high-current, high-voltage thyristor devices have a very serious pollution to the power grid, which leads to the fact that the power supply in the same power grid is not "clean." For example, in this power grid, there are high-power thyristor frequency modulation speed control devices, thyristor rectifier devices, thyristor AC-DC converter devices, and so on, all of which will cause pollution to the power supply. The solution to this situation is relatively simple, as long as the entire system is powered by a clean power supply or an online UPS.
3. There is a strong source of interference near the system. This can be judged through investigation and understanding. If this is the reason, the solution is to strengthen the shielding of the camera, as well as to ground the pipeline of the video cable.
Main business: TCL monitor , integrated camera , infrared waterproof camera , high-speed ball, video server
From Shenzhen Wei'ao Vision Technology Co., Ltd.