April 13, 2023
With development of security monitoring, many departments, communities, shopping malls and other places are equipped with closed-loop monitoring systems. The closed loop monitoring system can give people most direct visual and auditory experience, and visibility, real-time and objectivity of monitored object, which is convenient for us to check and collect evidence later.
But we can always hear news like this: mall has been stolen and surveillance is only obscure; White clothes!
Why closed monitoring remains unclear and how to support it in everyday life?
Causes of fuzzy CCTV images
1. Improper grounding of two devices at front panel and at control center causes a potential difference that forms a loop and enters system, causing a black or white line to appear on monitor screen and scroll up or down. .
2. Signal attenuation and high frequency coupling in transmission line will cause snowflake noise in monitor image.
3. The characteristic impedance between video transmission lines or devices is not 75 ohms, resulting in an impedance mismatch, causing video images to be doubled, images to be white, characters to tremble, or appear on monitor screen. several vertical stripes with same spacing.
4. The main wire of video cable and shield network are shorted or disconnected, which will cause single frequency interference.
5. Camera and lens resolution are incompatible
6. Focus is fuzzy
7. During installation, fingerprints and other contaminants were left on the lens
If you want precise control, following points are very important!
1. It is very important to choose a high resolution camera!
2. When choosing a plan, it should be as broad as possible. Horizontal use of five or more categories to enable data and voice exchange. Vertical use of optical fiber to increase logarithmic cables. For some buildings with a large number of points, fiber optics should be used for data backup instead of cables.
3. When monitoring wiring, low current must pass well through its own low current to reduce possibility of electromagnetic interference. Distribute as many points as possible, use a panel with two holes (one for voice, one for data), interact well with electricity, and place power points near data points.
4. When laying DG pipes, use pipes of a larger diameter and leave a margin. When laying optical cables, pay special attention to turning radius, if turning radius is too small, connection will be seriously lost.
5. Daily maintenance is very important Clean camera lens regularly with a lens cleaner. The company develops appropriate maintenance programs and creates maintenance funds.