The Ins and Outs of a VGA Port: Everything You Need to Know
The Ins and Outs of a VGA Port: Everything You Need to Know - Table of contents:
VGA (Video Graphics Array) is a computer display standard proposed by IBM in 1987 using analog signals. The VGA port is a special interface for the computer to output data using the VGA standard.
The VGA port has a total of 15 pins, divided into 3 rows, with 5 holes in each row. It is the most widely used interface type on graphics cards, and most graphics cards have this type of interface. It transmits red, green, blue analog signals and sync signals (horizontal and vertical signals).
What is a VGA port?
VGA (Video Graphics Array) is a video graphics array, which has the advantages of high resolution, fast display speed, and rich colors. VGA port is not only the standard interface of CRT display equipment, but also the standard interface of android monitor screen, and has a wide range of applications.
With the development of electronic industry and video image processing technology, VGA (Video Graphics Array) has been widely used in video and computer fields as a standard display interface. The high-resolution image is displayed on the monitor in real time.
Generally, the frequency of the crystal oscillator is required to be above 40MHz. Traditional electronic circuits are difficult to achieve this speed. If a special image processing chip is used, the design difficulty and high development cost become a bottleneck choice.
Causes of VGA port
Common interface color difference VGA interface (D-Sub interface)
When it comes to VGA interface, I believe that many friends are familiar with it, because this interface is the most important interface on computer monitors. Since the era of huge CRT monitors, VGA port has been used and has been used until now. Known as the D-Sub interface.
Many people think that only the HDMI interface can transmit high-definition signals, but this is a misunderstanding that everyone easily enters, because the connection through VGA can also display 1080P images, and even the resolution can reach higher, so use it to connect display devices Watching high-definition video is no problem, and although it is an analog interface, since VGA decomposes the video signal into R, G, B three primary colors and HV line and field signals for transmission, the loss in transmission is still quite small.
Reasons for the VGA interface: The information processed by the graphics card will eventually be output to the monitor. The output interface of the graphics card is the bridge between the computer and the monitor, and it is responsible for outputting the corresponding image signal to the monitor. CRT monitors can only accept analog signal input due to design and manufacturing reasons, which requires the graphics card to output analog signals.
The VGA port is the interface for outputting analog signals on the graphics card. The VGA (Video Graphics Array) interface is also called the D-Sub interface. Although LCD monitors can directly receive digital signals, many low-end products use VGA interfaces to match VGA interface graphics cards.
VGA port characteristics
The VGA interface is a D-type interface with a total of 15 pinholes, divided into three rows, five in each row. Among them, in addition to 2 NC (Not Connect) signals, 3 display data buses and 5 GND signals, the more important ones are 3 RGB color component signals and 2 scan synchronization signal HSYNC and VSYNC pins.
The color component in the VGA port adopts the RS343 level standard. The peak voltage of the RS343 level standard is 1V.
The VGA interface is the most widely used interface type on graphics cards, and most graphics cards have this type of interface. Some graphics cards without a VGA interface but with a DVI (Digital Visual Interface) interface can also convert the DVI interface to a VGA interface through a simple adapter. Usually, graphics cards without a VGA interface will come with such an adapter.
Most computers and external display devices are connected through an analog VGA port, and the display image information generated digitally inside the computer is converted into R, G, B three primary color signals and line and field by the digital/analog converter in the graphics card. Synchronous signal, the signal is transmitted to the display device through the cable. For analog display devices, such as analog CRT monitors, the signal is directly sent to the corresponding processing circuit to drive and control the picture tube to generate images.
For digital display devices such as LCD and DLP, a corresponding A/D (analog/digital) converter needs to be configured in the display device to convert the analog signal into a digital signal. After two conversions of D/A and A/D, some image details are inevitably lost.
There is nothing wrong with the application of VGA port to CRT monitors, but if it is used to connect display devices such as liquid crystals, the image loss in the conversion process will slightly reduce the display effect.
And you can judge from the interface whether the graphics card is a discrete display or an integrated graphics card. If the VGA interface is placed vertically, it means an integrated graphics card.
Features of VGA:
1. In theory, it can support 2048×1536 resolution screen transmission.
2. Since VGA is an analog signal transmission, it is susceptible to interference, and signal conversion is likely to cause signal loss.
3. Under 1080P resolution, the user can clearly feel the loss of the picture through the naked eye.
4. It is recommended to use monitors below 1080P resolution.