Six solutions easily deal with camera image problems

When the surveillance camera is installed and used, it often encounters some faults, such as no image, unclear image, focal length, etc. Some of these problems are caused by the camera itself, and some are caused by improper installation and use. This paper focuses on the surveillance camera. There are black map solutions for your reference.

1, camera status: bad line

Too many connectors or poor line contact, it is recommended to replace the line.

2, camera status: a number of vertical strip interference with equal spacing

Analysis of the cause: Since the characteristic impedance of the video transmission line is not 75Ω, it causes impedance mismatch. Or caused by the inconsistency of the characteristic impedance and distribution parameters of the video cable.

Solution: Generally, it is solved by the method of “starting series resistor” or “terminal paralleling resistor”.

3, the camera status: the appearance of wood-like interference

Analysis of the cause: The quality of the video transmission line is not good, especially the shielding performance is poor, and the line resistance is too large, thus causing a large attenuation of the signal. Or because the power supply of the power supply system is not "clean".

Solution: Change the video cable or add a sleeve. Power problems can be solved by simply using a clean power source or an online UPS for the entire system.

4, camera status: the line is too long

Cause analysis: The line is too long or the signal is attenuated

Solution: Due to the excessive loss of the high frequency end of the image signal, the signal at a frequency above 3 MHz is basically lost. In this case, the transmission distance is too far, and there is no amplification compensation device in the middle; or because the distributed capacitance of the video transmission cable is too large; or because of the concentrated distribution of the equivalent capacitance between the core wire and the shield wire of the transmission line in the transmission link As a result, a signal amplifier should be installed.

5, camera status: transformer failure

The power supply is unstable and the noise is too large. It is recommended to replace the transformer.

6, camera status: a black bar or white bar appears on the monitor screen

Analysis of the cause: The most common fault phenomenon is the 50-week power frequency interference. This phenomenon is mostly caused by the system loop that was generated by the system and the 50-week power frequency interference (AC interference). It is because the common end of the signal transmission line is grounded at both ends to cause repeated grounding; it may also be that the common end of the signal line is short-circuited with the zero line of the 220V power supply; or the common end of a device in the system is short-circuited with the 220V AC power supply; It is also possible that the signal line is generated by a strong magnetic field generated by the AC power source (if the two sides are too close together).

Solution: The solution is to connect the transformer into a longitudinal choke (also called a neutral transformer) or to use a “longitudinal choke” on the transmission line to better eliminate such interference.

If the camera has the above image problem, you can solve it by following the instructions in the small series. However, it is reminded that these solutions are not all image faults of surveillance cameras. If the problem is serious, experts need to deal with them.