[Multimedia] What is the VGA Interface?

The information processed by the video card is eventually output to the display card. The output interface of the video card is a bridge between the computer and the display card. It is responsible for outputting the corresponding image signal to the display card. The CRT display can only accept analog signal input for design and manufacturing reasons, which requires the video card to be able to input analog signals. The VGA interface is the interface that outputs analog signals on the video card. The VGA (video graphics array) interface is also called the D-sub interface. Although the LCD can directly receive digital signals, many low-end products use the VGA interface to match the VGA Interface graphics card. VGA interface is a type D interface, which has 15 blank pins and is divided into three rows, five in each row. VGA interfaces are the most widely used interfaces on graphics cards. Most graphics cards use this interface. Some graphics cards with DVI interfaces without VGA interfaces can also be converted into VGA interfaces through a simple Adapter. Generally, graphics cards without VGA interfaces are attached with such adapters.

Common DVI to VGA connector

 

Currently, most computers and external display devices are connected through a simulated VGA interface. The computer displays image information in digital mode, the digital/analog converter in the video card is converted into three primary color signals (R, G, and B), line and field synchronous signals, and the signals are transmitted to the display device through cables. For analog display devices, such as analog CRT display, the signal is directly sent to the corresponding processing circuit, and the driver controls the picture tube to generate an image. For LCD, DLP, and other digital display devices, the corresponding A/D (analog/digital) converter must be configured in the display device to convert analog signals to digital signals. After D/A and A/D2 conversions, some image details are inevitably lost. VGA interface is applicable to CRT display, but it is used to connect LCD and other display devices, the loss of the image during the conversion process will slightly decrease the display effect.