Advantages of VGA Video Extenders in Systems Engin
2021-04-13
With the project, home theaters use more and more large screens (plasma, rear projection, etc.), huge screens require higher definition, ordinary TV signals have not met the requirements, and the popularity of the network makes it easier to obtain good movie resources. Combined with the high definition of computer VGA video, many people propose to use the large screen of the home theater to play the movies downloaded from the computer, and use the high-definition video of the computer VGA to watch blockbuster movies. Various surveillance, information release and other projects also put forward the requirements of VGA video transmission. The standard transmission distance of VGA video often restricts this idea.
In order to solve the VGA transmission problem above the project, VGA signal amplifier began to appear, which adopts the principle of amplification, and uses VGA video cable as the transmission medium, which can transmit the VGA video signal of the computer for hundreds of meters. But then people found its defects, the long-distance VGA wire is thick and hard, not easy to find, needs to be customized in the factory, the wiring is extremely inconvenient, and the VGA head is also very prone to problems when welding. With the increase of distance, some interference that is not very strong also becomes strong in the long-distance cable, and some amplifiers amplify the interference signal together, resulting in some test environments can be successful but the actual engineering is not applied at all, resulting in a huge loss of rework. In order to solve these transmission problems, new technologies and ideas have emerged, and a VGA video extender using ordinary network cable (twisted pair) as the transmission medium has become the upstart of VGA video transmission technology.
The transmitter re-encodes the VGA video signal and transmits it on the network cable with differential signal technology, and decodes and restores it to the remote receiver into VGA. Due to the high frequency attenuation of the cable characteristics of the network cable, the restoration compensation technology of the back-end receiver is very important. If the technology is not handled well, there will be problems such as poor color reproduction effect and tail ghosting. Many products use graded and segmented DIP switches to adjust (many products in Taiwan and mainland China are using similar technology), this design idea is very good, but when actually used, it is often due to the different quality of the network cable used by the engineering company, the site environment is different, this method can not complete the purpose of accurate adjustment, and the user is also very troublesome when using it.
VGA video extender It uses differential technology with strong anti-interference performance, plus some technical processing, the anti-interference performance has been greatly improved. It can be used to transmit VGA video over long distances in even the harshest power plant environments with strong electrical and magnetic fields. Anti-interference is an important indicator to ensure the quality of the project, how to ensure the anti-interference of the product shows the level of R&D personnel who design circuits. The anti-interference effect of different products is different, and it is best for users with conditions to do interference testing when choosing products, and users without conditions are best tested on the spot or worse than the site before finalizing and purchasing. In this way, we can ensure that the quality of the project is recognized by Party A and that the cooperation between the two sides is pleasant.
The technology of twisted pair transmission of VGA video is to use 3 pairs of wires in the network cable to transmit the RGB signal of VGA video, and mix the HV two signal codes into RGB for transmission. It not only solves the internal crosstalk problem in long-distance transmission by using the characteristics of network cables, but also saves a pair of wires to transmit other signals, so that twisted pair transmission equipment has more functions and a wider range of applications. For example, our company's JD-1VGA mouse and keyboard extender uses the remaining pair of wires to transmit mouse and keyboard signals to realize real-time operation of remote customers. It can also be used to transmit audio signals or control signals. Of course, the simultaneous transmission of mouse, keyboard, VGA, and these three signals is more technically difficult and requires stronger anti-interference. The company has the patented technology of twisted pair cable transmission of various interface signals of computer peripherals and has been maintaining a leading position in this regard, providing better and more comprehensive products for engineering users.
The network cable is used as the wire material is cheap, the crystal head is easy to make, and the wiring is also convenient. At present, the price difference between VGA video extender and VGA signal amplifier is not large, the farther the distance, the lower the cost of the cable, and the better the anti-interference effect. It can be said that it is already a trend for VGA video extenders with distances of more than 30 meters to replace VGA signal amplifiers.
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