VGA: what is this cable, driver, graphics adapter? Pass me that picture! We study current interfaces for connecting monitors and televisions.

The resolution of digital and analog devices is exactly the same, but there are some differences in its definition. In analog devices, the image is built using so-called TV lines; this has been determined since the birth of television. IN digital equipment The image is constructed in a different way - using square pixels.

Resolution NTSC and PAL.
There are two standards in analogue television - NTSC and PAL. NTSC (National Television System Committee) standard television standards) is distributed mainly in North America and Japan, PAL (Phase Alternating Line - line-by-line phase change), on the contrary, is used in Europe and many Asian and African countries. NTSC has a resolution of 480 lines, and the picture refresh rate is 60 interlaced fields or 30 frames per second. New designation for the 480i60 standard defines the number of lines and refresh rate, and the letter "i" indicates interlace scanning. The PAL standard provides a resolution of 576 lines and a refresh rate of 50 fields or 25 full frames per second, and the new standard designation is 576i50. Both standards transmit exactly the same amount of information per second. When digitizing analog video information, the calculation maximum quantity pixels is based on the number of television lines, so there is a strictly defined maximum size digitized video material which is defined as D1 or 4CIF.

If we talk about purely digital and not digitized resolution, then everything is more flexible, and these types of resolution take their foundations in the computer environment, and have now become world standards. There are no restrictions on NTSC and PAL in this resolution. VGA (Video Graphics Array) is an IBM development designed specifically for displaying graphics on a PC. VGA resolution is 640x480 pixels. All computer monitors support this resolution and its analogues.

With all-digital network camera systems, you can achieve the added flexibility of a resolution that originated in the computing environment and is accepted standard all over the world. The limitations of NTSC and PAL standards no longer matter. VGA (Video Graphics Array) is a PC graphics display system developed by IBM. Its resolution is 640x480 pixels, a format usually used in non-megapixel network cameras. VGA resolution is generally more suitable for network cameras because VGA-based video uses square pixels that match those of computer monitors. Computer monitors support VGA resolution or its equivalent. This type resolutions are closer to network video surveillance systems.

Megapixel resolutions.
Modern video surveillance systems have come far ahead and are already significantly superior to analogue ones in image quality. Modern network cameras are capable of megapixel resolution, which means that their image sensor contains a million, and sometimes even more, pixels. Megapixel cameras show more detailed picture, you can easily see people’s faces or small objects on them. The ability to operate at megapixel resolution is one of the ways in which network cameras are superior to analog cameras. The maximum possible resolution of an analog camera after digitization by a DVR is D1 or 720x576. This corresponds to approximately 0.4 megapixels. Compared to megapixel format, standard definition here 1280x1024, which corresponds to 1.3 megapixels. This resolution exceeds analog cameras by more than three times, but this is not the limit because there are cameras operating in two and even three megapixel resolution. In addition to everything, megapixel resolution has another significant advantage. At this resolution, an image with different aspect ratios (the ratio of the width and height of the image) is formed. Regular TV works in 4:3 format, and some of the megapixel network cameras are capable of working in 16:9 format. The advantage of this format is that unnecessary video information is trimmed at the top and bottom, which can significantly reduce bandwidth and storage space requirements.

HDTV resolution.
This permission almost five times superior to standard analog systems, and in addition to this, HDTV has increased color clarity and, of course, has the ability to use the 16:9 format.
There are two main HDTV standards defined by the SMPE (Society of Motion Picture and Television Engineers):
SMPTE 296M (HDTV 720P) - this resolution is standardized as 1280x720 pixels in high definition color reproduction and 16:9 format with progressive scan 25/30 Hz. This corresponds to approximately 25-30 frames per second, depending on different countries and 50/60 Hz corresponding to 50-60 frames per second, respectively.
SMPTE 274M (HDTV 1080) is defined as a higher resolution of 1920x1080 pixels with high definition color, 16:9 aspect ratio, 25/30 Hz and 50/60 Hz interlaced progressive scan.
Video cameras operating in such standards provide high HDTV image quality, high resolution, clear color reproduction and high frame rates. This resolution is based on square pixels, just like computer monitors. If you use a progressive scan HDTV, there is no need to deinterlace the video image.

Our generation lives in the era of the scientific and technological revolution, but since we are “inside the process,” we do not notice the rapid change of generations around us technical devices. If earlier household appliances could serve for decades, but now in two or three years it becomes hopelessly outdated - new ideas, new technologies and materials appear that allow these ideas to be implemented.

Since the creation of the first spark transmitters radio-electronic equipment was analog. However, after World War II, when bipolar and field effect transistor, the first were developed integrated circuits, digital technologies have begun to gain their place in the sun. From a circuit design point of view, digital equipment is more complex than analog equipment, but its functionality is much wider, and some of them are fundamentally unattainable with analog signal processing. Despite this, in the field of modern television technologies, analog video signals are used very widely and are not going to become a thing of the past.

The problem with the digital representation of a video signal is that the width of its spectrum is many times greater than the width of the spectrum of the same video signal, but in analog form. Modern systems digital television, which are gradually being adopted throughout the world, are not capable of working with an uncompressed signal. It has to be encoded using the MPEG algorithm, which is known to be a lossy algorithm. So it turns out that despite the development and improvement of digital technologies, it is easier and cheaper to transmit a video signal to long distances use analog video formats: the signal spectrum width is quite acceptable, the equipment fleet is extensive, and the technologies have been developed to perfection.

Digital interfaces DVI and its development HDMI are, in general, interfaces of the near future, but they are intended to solve other problems.

Analog video signal used in modern television systems, can be composite and component.

Composite CV(composite video) – this is simplest form analog video signal, in which information about brightness, color and timing is transmitted in a mixed form. In the early stages of the development of video technology, it was the composite signal that was transmitted over a coaxial cable that connected VCRs or video players to televisions.

A more advanced version of the composite signal is the signal S-Video. This type of analog video signal provides separate transmission of the luminance (Y) signal and two combined chrominance (C) signals via independent cables, which is why this signal is also called YC. Because luma and chrominance signals are transmitted separately, S-Video occupies significantly more bandwidth than composite. Compared to a composite video signal, S-Video provides a noticeable gain in image clarity and stability, and to a lesser extent in color rendition. S-Video is widely used in semi-professional equipment, broadcast studios, and also when recording on 8 mm film in the Hi-8 standard from Sony.

For high definition television and computer video these interfaces are not suitable because they do not provide necessary permission images.

Component video signals

To achieve maximum image quality and create video effects in professional equipment, the video signal is divided into several channels. For example, in an RGB system, the video signal is divided into red, blue and green components, as well as a sync signal. This signal is also called the RGBS signal; it is most widespread in Europe.

Depending on the method of transmitting synchronization signals, the RGB signal has several varieties. If clock pulses are transmitted in a green channel, then the signal is called RGsB, and if the synchronization signal is transmitted in all color channels, then RsGsBs.

To connect the RGBS signal, use cables with four BNC connectors or a SCART connector.

RGBS video cable with BNC connectors.

SCART connector

Table 1. SCART connector pin assignments

Contact	Description
1.	Audio output, right
2.	Audio input, right
3.	Audio output, left + mono
4.	Audio Ground
5.	Ground for RGB Blue
6.	Audio input, left + mono
7.	RGB Blue input
8.	Input, switching TV mode, depending on the type of TV - Audio/RGB/16:9, sometimes turning on AUX (old TVs)
9.	Ground for RGB Green
10.	Data 2: Clockpulse Out, only in older VCRs
11.	RGB Green input
12.	Data 1 Data output
13.	Ground for RGB Red
14.	Land for Data, remote control, only in old VCRs
15.	RGB Red input or Channel C input
16.	Blanking Signal input, TV mode switching (composite/RGB), “fast” signal (new TVs)
17.	The land of composite video
18	Ground Blanking Signal (for pins 8 or 16)
19.	Composite video output
20.	Composite video input or Y (luminance) channel
21.	Protective screen(frame)

The YUV system, which has become widespread in the United States, uses a different set of components: mixed luminance and synchronization signals, as well as red and blue color difference signals. Each component system requires a different type of equipment, and each has its own advantages and disadvantages. To connect devices of different video formats, special interface blocks are required. The connectors at the ends of the cables are usually RCA or BNC.

YUV component signal

RGBHV format component signal

The way a video signal is formed is as follows: the image is decomposed into signals of three primary colors: red (Red - R), green (Green - G) and blue (Blue - B) - hence the name “RGB”, to which horizontal and vertical synchronization signals are added ( HV), and then turns into an RGB signal with sync pulses in the green channel (RGsB), which is further converted into: a component (color difference) signal YUV, where Y=0.299R+0.5876G+0.114V; U=R–Y; V= B-Y, which is then converted into S-Video and composite video. The composite video signal is converted into an RF signal that combines audio and video signals. It is then modulated by a carrier frequency and turned into a broadcast television signal.

At the receiving side, the radio frequency signal is converted as a result of demodulation into a composite video signal, from which, in turn, as a result of a series of transformations, RGB and HV components are obtained.

The YPbPr component signal is converted to RGB + HV, bypassing many video circuits. Separation of color difference signals Pb and Pr by individual channels significantly improves the phase accuracy of the color subcarrier, and color tone adjustment is not required.

High definition television signals (HDTV) 720p and 1080i are always transmitted in component format, HDTV in composite or s-video formats does not exist.

When was it born DVD format, it was decided that when digitizing material for recording on DVD, it was the component signal that would be converted into digital form and then processed using the MPEG-2 video data compression algorithm. The RGB signal output from a DVD player is derived from the YUV component signal.

It is important to note the difference between the ratio of color components in RGB and the component signal of the YUV format (YPbPr). In the RGB color space, the relative content (weight) of each color component is the same, whereas in YPbPr it takes into account the spectral sensitivity of the human eye.

Ratio of components in RGB color space

Component ratio in YPbPr color space

Limitations on the transmission distance of component types of video signals from signal sources to receivers are summarized in Table 2 (for comparison, some digital interfaces are also shown).

Signal type	Bandwidth, MHz	Cable type	Distance, m
UXGA (component) HDTV/1080i (component)	170 70	Coaxial 75 Ohm	5 5-30
Component UXGA (amplified)	170	Coaxial 75 Ohm	50-70
Standard (digital SDI) HDTV (digital SDI)	270 1300	Coaxial 75 Ohm	50-300 50-80
DVI-D	1500	twisted pair	5
DVI-D (amplified)	1500	twisted pair	10
IEEE 1394 (Firewire)	400(800)	twisted pair	10

VGA video signals

One of the most common types of component signal is the VGA format.

The VGA (Video Graphics Array) format is a video signal format designed for output to computer monitors.

By resolution, VGA formats are usually classified in accordance with the resolution of personal computer video cards that generate the corresponding video signals:

• VGA (640x480);
• SVGA (800x600);
• XGA (1024x780);
• SXGA (1280x1024);
• UXGA (1600x1200).

In each pair of numbers, the first shows the number of pixels horizontally, and the second shows the number of pixels vertically in the image.

The higher the resolution, the smaller sizes luminous elements and a better image on the screen. This should always be the goal, but as resolution increases, the cost of video cards and display devices increases.

Video technology is developing rapidly, and some computer formats, such as MDA, CGA and EGA are a thing of the past. For example, the CGA format, which was considered the most common format for several years, provided an image with a resolution of only 320x200 with four colors!

The weakest video format currently in use, VGA, appeared in 1987. The number of gradations of each color in it is increased to 64, resulting in the number of possible colors being 643 = 262144, which for computer graphics is even more important than resolution.

The pin assignments of the VGA connector are shown in the table.

Contact	Signal	Description
1.	RED	Channel R (red) (75 ohms, 0.7 V)
2.	GREEN	Channel G (green) (75 ohms, 0.7 V)
3.	BLUE	Channel B (Blue) (75 Ohm, 0.7 V)
4.	ID2	ID bit 2
5.	GND	Earth
6.	RGND	R channel ground
7.	GGND	G channel ground
8.	BGND	Channel B ground
9.	KEY	No contact (key)
10.	SGND	Earth Sync
11.	ID0	ID bit 0
12.	ID1 or SDA	ID bit 1 or DDC data
13.	HSYNC or CSYNC	Lowercase H or composite sync
14.	VSYNC	Frame synchronization V
15.	ID3 or SCL	ID bit 3 or DDC clocks

In addition to the video signals themselves (R, G, B, H and V), the connector (according to the VESA specification) also provides some additional signals.

The DDC (Display Data Channel) channel is designed to transmit a detailed “dossier” of the display to the processor, which, having familiarized itself with it, produces an optimal signal for this display with the required resolution and screen proportions. This dossier, called EDID (Extended Display Identification Data, or detailed display identification data), is a block of data with the following sections: brand name, model identification number, serial number, release date, screen size, supported resolutions and native resolution screen.

Thus, the table shows that if you do not use the DDC channel, then the VGA format signal is, in fact, a component RGBHV signal.

In professional equipment, instead of a D-Sub cable with a DB-15 connector, a cable with five BNC connectors is usually used, which provides better transmission line performance. Such a cable is better impedance-matched to the receiver and transmitter of the signal, has less crosstalk between channels, and is therefore better suited for transmitting high-resolution video signals (broad signal spectrum) over long distances.

VGA cable with DB-15 connector

VGA cable with five BNC connectors

Currently, the most widely used display devices are 4:3 aspect ratios: 800x600, 1024x768 and 1400x1050, but there are formats with unusual aspect ratios: 1152x970 (about 6:5) and 1280x1024 (5:4).

The rise of flat panels is pushing the market toward increased use of 16:9 widescreen displays with resolutions of 852x480 (plasma), 1280x768 (LCD), 1366x768 and 920x1080 (plasma and LCD).

The required link bandwidth for transmitting a VGA or video amplifier signal is determined as the product of the number of horizontal pixels times the number of vertical lines times the frame rate. The result obtained should be multiplied by a safety factor of 1.5.

W [Hz] = H * V * Frame * 1.5

The horizontal scanning frequency is the product of the number of lines (or rows of pixels) and the frame rate.

Signal type	Occupied frequency spectrum, MHz	Recommended max. transmission distance, m
Analog video signal NTSC	4,25	100 (RG-6 cable)
VGA (640x480, 60 Hz)	27,6	50
SVGA (800x600, 60 Hz)	43	30
XGA (1027x768, 60Hz)	70	15
WXGA (1366x768, 60Hz)	94	12
UXGA (1600x1200, 60Hz)	173	5

Thus, a UXGA signal requires a bandwidth of 173 MHz. This is a huge strip: it extends from audio frequencies to the seventh television channel!

How to lengthen a component signal

In practice, there is often a need to transmit video signals over distances greater than those indicated in the above tables. A partial solution to the problem is to use coaxial cables high quality, with low ohmic resistance, well matched with the line, and having a low level of interference. Such cables are quite expensive and do not provide a complete solution to the problem.

If the signal receiver device is located at a considerable distance, you should use specialized equipment - so-called interface extenders. Devices of this class help eliminate the initial limitation on the length of the communication line between the computer and elements of the information network. VGA signal extenders operate at the hardware level, so they are free from any compatibility issues software, codec negotiation or format conversion.

If we consider a passive line (i.e. a line without active terminal equipment), then an RG-59 cable is capable of transmitting composite video without visible distortion on the screen, television signal PAL or NTSC standards only at 20-40 m (or up to 50-70 m via RG-11 cable). Specialized cables such as Belden 8281 or Belden 1694A will increase transmission range by approximately 50%.

For VGA, Super-VGA or XGA signals received from computer graphics cards, normal VGA cable provides image transmission with a resolution of 640x480 over a distance of 5-7 m (and with a resolution of 1024x768 and higher, such a cable should not be longer than 3 m). High quality industrial cables VGA/XGA provide a range of up to 10-15, rarely up to 30 m. In addition, the communication line will be subject to losses at high frequencies (High frequency loss), which manifests itself in a decrease in brightness until color completely disappears, deterioration of resolution and clarity.

To eliminate this problem, you can use a linear amplifier-corrector connected BEFORE the long cable. It uses a high-frequency loss compensation circuit called EQ (Cable Equalization) or HF (High Frequency) control. The EQ circuit provides frequency-dependent signal amplification to “straighten” the amplitude-frequency response (AFC). The general gain control allows you to counteract normal (ohmic) losses in the cable.

Such linear amplifiers allow (using cables of maximum quality) to transmit a signal with a resolution of up to 1600x1200 (60 Hz) over distances of up to 50-70 m (and more, with lower resolutions).

However, this is not always enough: sometimes long distances are needed, sometimes a long cable can induce interference that a linear amplifier cannot combat. In this case the usual coaxial cable VGA can be replaced with another, more suitable media. Today, an inexpensive and convenient twisted pair cable is most often used for this, installing special converters (transmitter and receiver) at the ends of the cable.

The transmitting device of such an extender converts video signals into a differential symmetrical format, most suitable for twisted pair cables. On the receiving side, the standard video format is restored.

Use a regular cable for local Ethernet networks, category 5 and above. For video signals, unshielded cable (UTP) is best. Due to the low cost of such a cable, the entire signal transmission path usually does not increase in cost, despite the need to install additional devices.

This VGA signal extension method works well at distances up to 300 m.

Similar methods can be used to extend component signals of other types (YUV, RGBS, s-Video); the industry produces corresponding types of devices.

Note that VGA signal devices are usually well suited for transmitting YUV component video (and this is specified in their descriptions), if you use their R, G, B channels to transmit Y, U and V channels (H and V synchronization channels can be omitted use). Usually, it is enough to use adapter cables to match the type of connectors.

The transmission medium in extenders can also be optical fiber and wireless radio. Compared to twisted pair cables, optical fiber will significantly increase the cost, and wireless communication will not provide sufficient noise immunity and reliability, and obtaining permission to use it is not easy.

The maximum image resolution that the video card can generate.

Resolution determines the number of horizontal and vertical pixels from which an image is formed. The higher the resolution, the more detailed and informative the picture on the monitor turns out.

A high resolution may be needed to connect a large diagonal monitor or for professional graphics work. Modern professional video cards provide maximum resolution - up to 3840x2400.

It should be noted that the maximum resolution for different video outputs may differ. For example, many modern video adapters at the DVI output can generate an image with highest resolution 2560x1600, and for D-Sub - 2048x1536.

Video card connectors

The choice of video card can also be influenced by the monitor you have or are planning to purchase. Or even monitors (plural). So, for modern LCD monitors with digital inputs, it is very desirable that the video card have a DVI, HDMI or DisplayPort connector. Fortunately, all modern solutions now have such ports, and often all together. Another subtlety is that if you require a resolution higher than 1920x1200 via the digital DVI output, then you must connect the video card to the monitor using a connector and cable that supports Dual-Link DVI. However, now there are no problems with this anymore. Let's look at the main connectors used to connect information display devices.

Analog D-Sub connector (also known as VGA output or DB-15F), shown in Figures 4.2.1 and 4.2.2

Rice. 4.2.1 VGA connector.

Rice. 4.2.2 VGA connector.

This is a long-known and familiar 15-pin connector for connecting analog monitors. The abbreviation VGA stands for video graphics array (pixel array) or video graphics adapter (video adapter).

DVI connector (variations: DVI-I and DVI-D), shown in Figures 4.2.3 and 4.2.4

Rice. 4.2.3 DVI connector.

Rice. 4.2.4 DVI connector.

DVI is the standard interface most often used to output digital video to all but the cheapest LCD monitors. Figure 6 shows a fairly old video card with three connectors: D-Sub, S-Video and DVI. There are three types of DVI connectors: DVI-D (digital), DVI-A (analog) and DVI-I (integrated - combined or universal):

HDMI connector

Recently, a new home interface- High Definition Multimedia Interface. This standard provides simultaneous transmission of visual and audio information over a single cable, it is designed for television and cinema, but PC users can also use it to output video data using the HDMI connector.

HDMI is the latest attempt to standardize a universal connection for digital audio and video applications. It immediately received strong support from the giants of the electronics industry (the group of companies involved in developing the standard includes companies such as Sony, Toshiba, Hitachi, Panasonic, Thomson, Philips and Silicon Image), and most modern high-resolution output devices have although There would be one such connector. HDMI allows you to transmit copy-protected audio and video in digital format over a single cable; the first version of the standard was based on a bandwidth of 5 Gbps, and HDMI 1.3 expanded this limit to 10.2 Gbps.

HDMI 1.3 is an updated standard specification with increased interface bandwidth, increased clock frequency to 340 MHz, which allows you to connect high-resolution displays that support more colors (formats with color depths up to 48 bits). The new version of the specification also defines support for new Dolby standards for transmitting compressed audio without loss in quality. In addition, other innovations appeared; specification 1.3 described a new mini-HDMI connector, smaller in size compared to the original, shown in Figure 4.2.5 Such connectors are also used on video cards.

Rice. 4.2.5 mini-HDMI connector.

HDMI 1.4b is the latest new version of this standard, published not so long ago. HDMI 1.4 introduced the following major innovations: support for stereo display format (also called "3D") with frame-by-frame transmission and active viewing glasses, support for Fast Ethernet connection HDMI Ethernet Channel for data transmission, audio return channel, which allows digital audio to be transmitted in the reverse direction , support for resolution formats 3840×2160 up to 30 Hz and 4096×2160 up to 24 Hz, support for new color spaces and the smallest micro-HDMI connector, shown in Figure 4.2.6

Rice. 4.2.6 micro-HDMI connector.

In HDMI 1.4a, stereo display support has been significantly improved, with new Side-by-Side and Top-and-Bottom modes in addition to the 1.4 specification modes. And finally, a very recent update to the HDMI 1.4b standard occurred just a few weeks ago, and the innovations of this version are still unknown to the general public, and there are no devices supporting it yet on the market.

DisplayPort connector

Gradually, in addition to the common video interfaces DVI and HDMI, solutions with the DisplayPort interface are appearing on the market. Single-Link DVI transmits a video signal with a resolution of up to 1920x1080 pixels, a frequency of 60 Hz and 8 bits per color component, Dual-Link allows transmission of 2560x1600 at a frequency of 60 Hz, but already 3840x2400 pixels under the same conditions for Dual-Link Link DVI not available. HDMI has almost the same limitations, version 1.3 supports signal transmission with a resolution of up to 2560x1600 pixels at 60 Hz and 8 bits per color component (at lower resolutions - 16 bits). Although DisplayPort's maximum capabilities are slightly higher than Dual-Link DVI's, only 2560x2048 pixels at 60 Hz and 8 bits per color channel, it does have support for 10-bit color per channel at 2560x1600 resolution, as well as 12 bit for 1080p format.

The first version of the DisplayPort digital video interface was adopted by VESA (Video Electronics Standards Association) in the spring of 2006. It defines a new universal digital interface, license-free and royalty-free, designed to connect computers and monitors, as well as other multimedia equipment. The VESA DisplayPort group promoting the standard includes large electronics manufacturers: AMD, NVIDIA, Dell, HP, Intel, Lenovo, Molex, Philips, Samsung.

DisplayPort's main rival is HDMI connector with support for HDCP write protection, although it is intended more for connecting household digital devices, like players and HDTV panels. Another competitor could previously be called Unified Display Interface - a less expensive alternative to HDMI and DVI connectors, but its main developer, Intel, refused to promote the standard in favor of DisplayPort.

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- Extension (format) is the characters at the end of the file after the last dot.
- The computer determines the file type by its extension.
- By Windows default does not show file name extensions.
- Some characters cannot be used in the file name and extension.
- Not all formats are related to the same program.
- Below are all the programs that can be used to open a VGA file.

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Most modern computer users mobile devices or television panels came across such a concept as VGA. What is it - a connector, video adapter, monitor, driver, cable or adapter? Unfortunately, many of us, as a rule, do not have a clear understanding of this issue. Therefore, it is worth dwelling on this standard in a little more detail.

VGA: what is it in a general sense?

First, a few words about the standard itself. In the broadest sense, VGA is not the individual components listed above, but an integral component-type video interface, originally developed by IBM for its computers.

Thus, the understanding of the entire technology for reproducing or transmitting images includes both hardware and software components, and the functioning of the interface consists of their interaction.

History of the standard

Now a few words about the emergence of the VGA video standard. What is it, we figured it out a little. The technology was first introduced by IBM in 1987 on PS/2 computers.

The VGA adapter, unlike its predecessors and successors, used (and still uses) for high-quality image transmission analog signal. But along the way, the question arises about why the introduction of a new standard was necessary. To fully understand this solution, you need to refer to the basic parameters of the devices themselves.

Main Features

Most experts cite the first and one of the main factors in the transition to this standard as the fact that initially it was necessary to reduce the number of wires in the main cable with the ability to connect system units via graphics adapter VGA to the corresponding monitors, which were capable of transmitting many more colors and shades than before. At the same time, a higher picture resolution was achieved.

Today it has a structure that includes the following elements:

• graphics controller for exchanging data between video memory and central processor based on bit operations with data;
• 256 KB DRAM video memory, divided into four color layers;
• serial converter of video memory data into bits for transferring attributes to the controller;
• an attribute controller for converting input data into palette-based color values;
• synchronizer for controlling switching layers and timing parameters of the graphics adapter;
• cathode ray tube controller to generate synchronization signals with the monitor.

Provided that the VGA driver is installed in the system, the maximum resolution is 640x480 pixels per inch with a color depth of up to 32 bits. Of course, at the time the standard appeared, it was truly a revolution. But today you can find much greater resolutions, which is achieved through the use of digital technologies. But as it turns out, even at the current stage of development computer equipment The VGA standard cannot be discounted. What does it mean? The only thing is that, as already mentioned, to transmit the image, an analog signal is used, which can be converted to any other. In addition, the size of the adapter itself is significantly reduced, and it can be integrated directly into the motherboard or additionally into the video card.

Here it is also worth paying attention to the fact that the digital signal has a wider bandwidth, and MPEG encoding technology is used to transmit such a signal. And this, in turn, leads to a loss of quality.

VGA monitors and TVs

Since the advent of the main standard, corresponding monitors have also begun to be actively used, and then television panels of this interface (for example, LCD devices).

Today, this abbreviation is used to denote all graphics modes, including monitors that are capable of supporting a resolution of 640x480 pixels, regardless of the hardware component. At the current stage of development, they are practically not used, although at one time they were very popular.

Graphics adapters

Almost all modern graphics accelerators (video cards), whether integrated or discrete, support the main modes of the described interface and are equipped with appropriate outputs (ports), which are sometimes also referred to as D-Sub.

In other words, a video card can have several video outputs. And a VGA connector is required. By the way, such connectors can be found on rear panels stationary system units and on the side walls of laptops.

Drivers

It goes without saying that no graphics accelerator will work unless the appropriate driver is installed for it (including the VGA driver).

But for modern video cards such control programs need to be installed not from databases operating systems, but from distribution kits of equipment manufacturers. In addition, today management or overclocking utilities supplied for the most popular NVIDIA cards and Radeon.

Many gamers can verify that the VGA driver works correctly by setting the video mode to 640x480 or its non-standard variations in the game settings. Actually, the same situation is observed when connecting a computer or laptop to a high-resolution TV panel if a VGA cable is used (and not only with the same type of connectors on both sides).

Types of cables and adapters

Since there are quite a lot of options for connecting to completely different video interfaces, it is worthwhile to dwell separately on cables with adapters that can be used to convert image transmission according to a scheme that will be recognized by both the receiving and transmitting devices.

As an example, consider a VGA cable with different options transitions. Among the main ones (besides the usual type) are the following:

• VGA-DVI (used on some video cards that do not have a VGA connector, although they support the corresponding operating modes);
• VGA-HDMI (can be used to connect older computers or laptops to modern TVs and projectors);
• VGA-RCA or VGA-tulip (used to connect modern computer systems, not equipped with VGA connectors, to old TVs or monitors with cathode ray tubes ELP);
• VGA-HDMI-RCA-mini-Jack (a variation of combining the two previous adapters for connection with audio transmission - sound is not transmitted through VGA);
• VGA-S-Video (a less popular option for connecting to TVs).

The main connector of the standard, also designated as DE15F, in any of the variants is a 15-pin connector on one side, which allows you to transmit a signal based on progressive scan technology, in which a change in voltage corresponds to a change in the brightness of the ELP (the intensity of the monitor gun beam or kinescope).

Brief summary and conclusions

That's it for understanding VGA. What is it? In fact, it is the interface, and not its individual components, necessary for correct functioning. And as you may have already noticed, it is present in most modern computer devices. Although the prospects for the development of such technologies look very vague, nevertheless, no one is going to abandon them yet.

It remains to add that this standard, despite the appearance of its followers in the form of the same Super VGA or XGA interface, still remains one of the most popular and in demand all over the world and on all types of devices, including computers, laptops, television panels or even mobile devices gadgets.