Esquema de transmisión de señal de pantalla LED a larga distancia

I am a technical engineer of LEGIDATECHE LED display screen.

Today, I will explain the long-distance transmission scheme of LED display screen signals, mainly focusing on Nova’s photoelectric conversion equipment and Novastar’s control system.

And how to arrange system equipment and signal lines in different application scenarios.

The signals of the LED display screen control system are generally transmitted through network cables.

Due to the large venue and many devices, large venues are placed in a designated position, and the distance between the controller and the receiving card will be relatively far.

The transmission distance of a general network cable is about 80 meters.

If this transmission method is used, due to the attenuation or reflection of the signal during transmission, black screen, flashing screen and other faults may occur during playback.

In addition, the long distance between the video source and the controller or video processor is also a problem that needs to be solved.

The maximum transmission distance of ordinary DVI line is only 5m, and the transmission distance of HDMI line is about 30m.

When it exceeds this range, the signal will attenuate during transmission, causing the screen to flash screen, flash point and other faults during playback.

To sum up, in the large-scale event site, to solve the long-distance transmission problem, it is necessary to solve the signal attenuation problem caused by the two types of wires, that is, the network cable and the video cable are too long.

The usual treatment in the industry is as follows.

 Photoelectric converter, also known as fiber optic transceiver, the common photoelectric converter architecture is shown in Figure 1-1.

The controller converts the image content to be displayed into an electrical signal, which is then transmitted to the photoelectric converter via a network cable.

The photoelectric converter converts the electrical signal into an optical signal, which is then transmitted over long distances via optical fiber.

Finally, the optical signal is transmitted to the receiving card via another photoelectric converter, and the image is finally displayed on the LED display.

1-1

The use of optical fiber video transmission to complete the long-distance transmission of video signals

The common fiber-optic video transmission architecture is shown in Figure 2-1.

Taking DVI signal transmission as an example, the video processor transmits the DVI signal to the DVI to fiber device, as shown in Figure 2-1.

After conversion, the DVI signal is converted into an optical signal and transmitted over long distances through optical fiber.

After that, the optical signal is converted into a DVI signal at the other end and transmitted to the controller.

After the controller processes the signal, it is transmitted to the receiving card, and finally the image is displayed on the LED display.

2-1

Optical fiber is used for long-distance transmission. The signal can be stably transmitted to the corresponding terminal by taking advantage of the strong anti-interference ability and long transmission distance of optical fiber during the transmission process.

Thereby meeting the scenario where the large screen is too far away from the device or signal source.

In addition, the characteristics of optical fiber transmission, such as wide bandwidth, large communication capacity and strong confidentiality, also enable the above two transmission schemes to be used in special environments.

as the application field of LED display continues to expand and the project is getting bigger and bigger, long-distance transmission has become

an essential part of the LED display control system, the industry has a variety of common optical fiber solutions and supporting equipment.

These devices are easy to obtain and have a wide range of applications, effectively solving the problems of most projects of general size.

However, for some important occasions or major projects, in order to avoid uncertainties such as equipment compatibility and reduce potential risks brought by different manufacturers and different hardware platforms.

In many cases, a complete set of solutions is needed, including long-distance transmission solutions.

Therefore, in addition to supporting common optical fiber equipment, various manufacturers in the industry will also develop their own special equipment.

In order to solve the long-distance transmission problem, Nova Nebula has designed a series of optical fiber transmission equipment to adapt to different application scenarios, such as photoelectric converter CVT310/CVT320, CVT-Rack310/CVT-Rack320, CVT10, CVT4K, etc.

In addition, some high-end LED sending cards are integrated with optical fiber interfaces, which can directly output optical fiber signals, such as MCTRLAK and H series products.

There are also some LED controllers with photoelectric conversion mode, which can freely switch the working mode between the controller and the photoelectric converter.

One machine is dual-purpose, which reduces the cost for end users, especially rental users, such as MCTRL660 PRO, K16, etc.

Depending on the transmission rate of the fiber optic interface, the photoelectric converter can be divided into a variety of different specifications, the common ones are 1 to 1, 1 to 8, 1 to 10, etc.

When the transmission rate is 1.25Gbits, the photoelectric converter is 1-to -1 type, I .e. one optical fiber interface transmits data of one network port correspondingly.

When the transmission rate is 9.9Gbits (also called 10G optical fiber), the photoelectric converter is 1-to -8 type, I .e. one optical fiber interface transmits data of 8 network ports correspondingly.

When the transmission rate is 11.3Gbit/s, the photoelectric converter is 1-to -10 type, that is, one optical fiber interface transmits data of 10 network ports.

Take CVT310/CVT320 as an example. CVT310/CVT320 is a 1-to -1 photoelectric converter.

There is only one network port and one optical fiber interface in its panel, which can convert one optical fiber into one network cable or one network cable into one optical fiber.

It is suitable for scenes with a small number of network cables and a long distance. Using such equipment in a slightly larger project would overcomplicate the system.

For example, a project uses K16 with LED display screen. If all the 16 output network ports of K16 are transmitted, 16 pairs of 32 sets are required.

CVT310/CVT320,CVT310/CVT320 system architecture as shown in Figure 3-1. This solution requires too many devices, which will lead to an increase in the number of nodes that may cause problems.

When installed on site, the number of equipment and network cables is large, which will also lead to bloated system architecture.

3-1

For large event venues, this type of solution is obviously not the best choice.

In order to simplify the long-distance wiring of large venues and solve the problem of bloated system architecture, you can choose a model with a higher transmission rate.

For example, choose CVT10 and other models.

This is a 1 to 10 photoelectric converter, which can not only be used as a traditional photoelectric converter to meet the photoelectric conversion needs of 10 network ports, but also can be directly used with the sending card with integrated fiber optic interface.

The optical signal output by the sending card is directly converted into an electrical signal. The number of output network ports after conversion is determined according to the number of network ports corresponding to each fiber optic interface of the sending card.

The CVT10 dual-device architecture is shown in Figure 3-2, and the CVT10 single-device architecture is shown in Figure 4-57.

Taking K16 as an example, because each optical fiber interface of K16 corresponds to 8 network ports, after CVT10 and K16 are connected through optical fibers, CvT10 becomes an output device with 8 network ports.

3-1

3-2

For large LED display important projects, you can also choose a more professional product:

CVT4K. It not only supports 4 optical fiber interfaces, each optical fiber can transmit 8 network ports, but also supports 2 Main and 2 standby between 4 network ports, which is more convenient for on-site wiring and setting up backup.

In addition, some controllers also integrate fiber interface backup functions, such as MCTRL1600, MCTRL4K, K16, etc. The fiber backup architecture is shown in Figure 3-3.

3-3

In addition to the Nova Nebula, various control system manufacturers have also developed related photoelectric conversion equipment.

For example, the photoelectric conversion scheme of Lingxingyu mainly uses SC801/mc801. This type of product is single-port conversion, and the system architecture is similar to that of Nova Nebula CVT310/cvt320.

Carlet’s photoelectric conversion scheme mainly uses photoelectric converters H2F, H16F, H10FN.

H2F is similar to Nova Nebula CVT10.

You can use two devices to cooperate with the sending card, first convert the electrical signal output by the sending card into an optical signal for transmission, and then convert the optical signal into an electrical signal and output it to the receiving card.

Or you can directly receive the optical signal output by the sending card, convert it into an electrical signal and output it to the receiving card.

H16F is similar to the Nova Nebula CVT320 scheme, and H10FN is similar to CVT10.

when the distance between the LED display and the control system is more than 80 meters, we need to use the photoelectric conversion equipment to avoid the attenuation of the LED display signal.