Split signal and noise on the screen

Sometimes you need to display a picture on several sources (for example, TVs) and some interference may occur. So here is the information on how to divide the signal and correct the arising interference.

Signal separation.

There are times when you need to get from one video source to multiple receivers, for example, the output of a singal from a video-eye to the intercom (small TV) near the door and to the recorder (for recording).

If there are two receivers of signal power, usually there is enough a tee with F connectors or a connecting tee for the BNC connector.



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In extreme cases, the wires can be soldered.

If there are more than two receivers, then the problems begin. Connection options:

• First connect to the recording device, and from its output (everyone usually has it) connect the remaining two (if there are three devices).
• Use matching tools, but this may not always help.
• Use an amplifier with a splitter (amplifiers, splitters).

Amplifiers splitters

Last and consider more.

For example, SC & T's CD102A device distributes a video signal with a gain of 1 input to 2 outputs, a transmission distance of 1000 m using an RG-59 cable.

Video Amplifier 1 input / 2 output

broadband, 10 dB gain;
correction of high frequencies of the video signal;
adjustment of clarity and brightness, perfect for systems with DVRs;
provides signal transmission via coaxial cable (RG-59) up to 1000 m;
power supply: 12 V (DC.) / 24 V (AC);
power availability indicator;
power supply included.



There are similar devices with division into 8 CD408A channels and 16 CD816A channels, they have counterparts without CD408 and CD416 correction, respectively.

It can be found on 32 and 64 channels, but they are rarely used and usually expensive.

Screen noise correction

Lightning protection.

Lightning protection devices are used to protect the station (video recorders, monitors, amplifiers, etc.) and peripheral equipment (video cameras, amplifiers, rotators, etc.) from high voltage arising in cable lines due to:

1. lightning discharges,
2. industrial interference
3. welding work
4. works of powerful power plants

There is a single-channel lightning protection with different connectors to protect coaxial cable and twisted pair: BNC, F, UTP. There are multi-channel, for example, 16 channels SP016C.

Surge protection protects video surveillance circuits, local area networks (LANs), power supply and control circuits.

Insulators.

1. Insulators allow you to eliminate the distortion of the video image caused by parasitic current due to the potential difference of the earth.
2. The parasitic current arises due to the difference in ground potential (due to unbalanced operation of the power grid) at various points in the video surveillance system and flows through the cable, introducing distortion.
3. Insulators protect equipment from high voltage (up to 380V AC) that occurs between different ground points and caused by unstable power supply.
4. Insulators are designed to isolate the system’s circuits from the “ground” (from the circuits connected to the earth circuit).
5. Isolators should be used when the video signal is transmitted via cable between points with different “ground” potential.
6. Isolators can be easily installed into newly created systems, or added to existing ones.

An insulator for coaxial cable with built-in noise filter GB001 or similar for a twisted pair TGP001 (with a built-in transceiver) prevents “gaps”, “overlapping” of the image and flickering of frames caused by parasitic ground current.

Matching devices.

Matching devices, or they are also called transfilters, remove frame flashing or image “overlap”, image “split”, usually caused by a distortion or a low level of sync signal in a video signal. The reason for this is usually the “attenuation” of the video signal, when transmitting it over long distances, interference and poor matching of cable lines and video equipment. Matching devices and filters are intended to solve these problems.



The matching device for coaxial cable CB001VH is designed to eliminate interference caused by poor matching of the resistance of cable lines and cable lines to equipment; input / output: BNC-plug / BNC-socket; passive, does not require power; it is installed at the points where the coaxial cable lines are connected and where the cable lines are connected to the equipment; protects against interference caused by radio signals, other video signals, nearby power cables, telephone sets, fluorescent lamps, transformers, etc.

There is a matching device for the twisted pair TVB001, which is designed to eliminate interference caused by poor matching of the resistance of cable lines and cable lines to equipment; passive, does not require power; is installed at the twisted pair junction points for matching resistance; 4 connecting clips of AP007 (adhesive tape) are included in the package.

Filters.

High-frequency noise filter CHB001H, remove high-frequency noise. Transmits and receives video and audio signals via a single coaxial cable RG6 over a distance of 600 m via RG59 to 400 m, or over one twisted pair (UTP cable) up to 180 m. With gain control in CHB001RH. The kit includes: transmitter - CHB001TH, receiver - CHB001RH, two power supplies.

Examples of devices (filters).

PS All devices are listed by Taiwanese firm SC & T. More information about them can be found here. Many devices have Russian counterparts, the price does not differ much (Russian counterparts are 5-15% cheaper).