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Several misunderstandings and differences Of VGA, DVI, HDMI
Jan 05, 2018

Today we gonna  have a deeper understanding of VGA, DVI, HDMI their differences and characteristics.


1.Some misunderstandings about VGA, DVI, HDMI

    Misunderstanding 1: HDMI is high definition, VGA is not

These three are not the same relationship, HDMI and VGA are the signal transmission, and high definition is a video resolution. HDMI support HD, VGA also support. HDMI currently supports up to 3840 × 2160P HD format, VGA support from 640 * 480 up to 2560 * 1600 of various resolutions. However, VGA is very susceptible to other signals, so the HD resolution seems a bit virtual, in order to avoid the picture interference, in the 1920 * 1080P resolution below, you can use the VGA interface.

   Misunderstanding 2: HDMI high bandwidth, low VGA bandwidth. So HDMI is better than VGA.

HDMI bandwidth is the digital signal bandwidth, VGA is the analog signal bandwidth, which is the transmission of two different technologies. If you want to compare, you can compare the transmission of the same resolution, such as high definition, HDMI requires 1536kHz bandwidth, and VGA only needs 172MHz bandwidth. But the high bandwidth does not mean that HDMI transmits more video signals, just because of the different transmission technologies.

  Misunderstanding 3: HDMI signal does not require digital to analog conversion, no signal loss; VGA signal requires digital to analog conversion, signal loss. Although HDMI does not require digital-analog conversion, but still have to go through the number of digital conversion. No matter what kind of conversion process it is, what it is converted into is, after all, a description of the analogue electrical signal. Their relationship. Digital signal describes the signal is composed of a single point in the signal change is inconsistent, and the analog signal changes is a continuous curve, so the artificial reality of the analog signal is better.

When the digital signal is converted to an analog signal, there are also points (digital signal sampling points) that come out directly, and parts that are not described are automatically generated by the conversion program (similar to 3D anti-aliasing technology) to form a continuous Analog signal waveform. When converting an analog signal to a digital signal, the continuous analog signal is converted into a digital signal that describes each point and the signal becomes incomplete.

From this process, the digital signal is converted to an analog signal is enhanced rather than loss, and the analog signal is converted to digital signal loss. In the VGA transmission process, VGA to LVDS driver LCD panel signal loss can be ignored, because the front and back end of the digital sampling rate the same circumstances, the loss of the signal is already (the digital signal into an analog signal) Automatic The part to be filled is not the loss of the original signal of the digital signal source.

2. VGA, DVI, HDMI features


VGA (Video Graphics Array) There is also a name D-Sub. Is an analog signal, can only transmit video signals, a total of 15-pin VGA connector, divided into 3 rows, each row of 5 holes, is the most widely used graphics interface type, the vast majority of graphics cards are equipped with this interface. It transmits red, green and blue analog signals as well as sync signals (horizontal and vertical signals). VGA connection device, the cable length is best not to exceed 10 meters, but also pay attention to whether the connector is securely installed, otherwise it may cause virtual shadow in the image, the other VGA can only transmit VGA support at higher resolution of 640 × 480 Display 16 kinds of colors or 256 kinds of grayscale, at the same time in 320 × 240 resolution can display 256 colors at the same time.



1, is the analog signal transmission, with the resolution of the monitor the higher the picture will be more blurred. General analog signals in the case of more than 1280 × 1024 resolution will appear obvious error.

2, because it is analog information, the signal is extremely vulnerable to interference.

3, can not convey the audio.

4, generally do not add amplifier and converter at about 30 meters, plus amplifier and amplifier can be up to 150 meters.


DVI that digital video interface, is a high-speed digital signal transmission technology, no longer undergo digital-analog conversion. DVI interface has a variety of specifications, common DVI-A, DVI-D and DVI-I. DVI video transmission avoids the digital-analog conversion of the transmitting end (usually a graphics card) and the receiving end (usually an LCD display) during analog video signal transmission, and also avoids the noise interference during the transmission of analog signals Problem, so no image loss.



1, digital signal, to avoid the A / D conversion process, the signal is not decay, the color is more pure, realistic.

2, only send video signal, do not send audio signal.

3, supports a variety of formats, including 1920 * 1080 all HD formats.


High Definition Multimedia Interface (HDMI) is a digital video / audio interface technology, is a dedicated digital interface for video transmission, which can simultaneously transmit audio and video signals, the maximum data transfer speed of 18Gbps . There is no need to perform D / A or A / D conversions before signaling.



1, can send uncompressed audio signals and high-resolution video signals, digital signals, high quality.

2, improve up to 18Gbps data transmission bandwidth.

3, the maximum can support 4K video. 


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