First, let’s analyze the breakdown and overhaul
The video signal is that after the video matrix is switched, the image displayed on the main monitor is overlapped with the shadow of another image. This is because another image signal is serialized into the signal. When the main image is displayed brighter, The shadow signal of another image stringed in by the signal amplitude of this channel is too large. The shadow is covered up, so it looks unbearable, but in fact it still exists. When the main screen image is relatively dark, it is stringed into another image. When the amplitude of the image signal of one channel is comparable to the amplitude of the main image signal displayed by the video matrix switching output, the overlapping shadow of the camera's image will look more obvious.
The main reasons for this failure are as follows:
1. The 75Ω coaxial cable or system is poorly grounded.
2. The isolation of the video matrix is too small and does not meet the technical requirements, so the replacement method should be used to quickly determine.
3. The video signal transmission line is not good, such as using low-quality cables, or the routing between the 75Ω coaxial cables of the signal being transmitted is extremely unreasonable, causing serious signal induction and crosstalk between the cables.
Fourth, the load impedance is seriously mismatched.
5. The wiring in the system is seriously unreasonable and crosstalk is selected.
6. In the high-frequency wired transmission mode and wireless transmission mode multimedia TV monitoring system, the system's crosstalk modulation and intermodulation are too large.
