There are often many unexpected situations in video surveillance, such as unclear images, ghosting, and jitters. In fact, its own security monitoring system is a very complex technical engineering project, and there are many reasons for the final result of interference. If the line connection is not very good or wrong, or the performance of the device is degraded, the parameters are not set well, etc. Here, we summarize some common faults and analysis in the video monitoring matrix.
1. A black bar or white bar appears on the monitor screen and scrolls up or down, which is the so-called 50 Hz power frequency interference. This kind of interference is caused by the potential difference loop caused by the improper grounding of the two devices at the front end and the control center. It may also be caused by the degradation of the power supply performance of the device itself.
2, the image has snow noise, this type of interference is mainly caused by signal attenuation on the transmission line and coupled with high frequency interference;
3, the video image has ghosting, or the image is whitish, the character is dithered, or a number of vertical bars with equal spacing are generated on the screen of the monitor. This is because the characteristic impedance between the video transmission line or the equipment is not 75Ω, resulting in impedance mismatch;
4, twill interference, beating interference, power interference. When this interference is slight, it does not overwhelm the normal image, but when it is severe, the image is distorted and cannot be viewed. The reasons for this are more and more complicated. For example, the quality of the video transmission line is not good, especially the shielding performance is poor, or the power supply system has clutter, or there may be a strong interference source near the system.
5, large area moire interference, also known as single-frequency interference. This phenomenon is mainly caused by the short circuit caused by the short-circuit of the video cable's core wire and the shield, or the failure caused by the open circuit, or due to the bad contact of the BNC connector.
6, equipment failure caused by power problems, there are the following possibilities: the power supply line or the supply voltage is not correct, the power is not enough (or a line power supply line enough, step-down, etc.), the power supply system transmission line appears Short circuit, open circuit, instantaneous overvoltage, etc.
1. A black bar or white bar appears on the monitor screen and scrolls up or down, which is the so-called 50 Hz power frequency interference. This kind of interference is caused by the potential difference loop caused by the improper grounding of the two devices at the front end and the control center. It may also be caused by the degradation of the power supply performance of the device itself.
2, the image has snow noise, this type of interference is mainly caused by signal attenuation on the transmission line and coupled with high frequency interference;
3, the video image has ghosting, or the image is whitish, the character is dithered, or a number of vertical bars with equal spacing are generated on the screen of the monitor. This is because the characteristic impedance between the video transmission line or the equipment is not 75Ω, resulting in impedance mismatch;
4, twill interference, beating interference, power interference. When this interference is slight, it does not overwhelm the normal image, but when it is severe, the image is distorted and cannot be viewed. The reasons for this are more and more complicated. For example, the quality of the video transmission line is not good, especially the shielding performance is poor, or the power supply system has clutter, or there may be a strong interference source near the system.
5, large area moire interference, also known as single-frequency interference. This phenomenon is mainly caused by the short circuit caused by the short-circuit of the video cable's core wire and the shield, or the failure caused by the open circuit, or due to the bad contact of the BNC connector.
6, equipment failure caused by power problems, there are the following possibilities: the power supply line or the supply voltage is not correct, the power is not enough (or a line power supply line enough, step-down, etc.), the power supply system transmission line appears Short circuit, open circuit, instantaneous overvoltage, etc.
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