Composite monitor
From Wikipedia, the free encyclopedia
A composite monitor is any analog video display that receives input in the form of an analog composite video signal through a single cable — in contrast to multiple-cable or multiple-wire video sources such as VGA cable. A monitor is different from a conventional TV set because it does not have an internal RF tuner or RF converter that can receive signals from an over-the-air broadcast TV station; however a user can install an external device that emulates a TV tuner (e.g. VCR, cable box, etc.) . A video display that is a "monitor-only" is useful for security cameras, some computers, and many other devices.
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[edit] Inputs
Composite monitors often have RCA jacks or BNC connectors for video input. Older (1970s) used UHF connectors.
Composite and S-Video are used in PAL and NTSC regions.
Composite monitors can be very high quality, with professional broadcast reference displays costing $10k-$15k (USD) as of the year 2000.
Note that all composite monitors imply the use of a CRT for display, and for color signals anyway, the composite signal must be "decoded" into its three components of red, green and blue to be fed to each gun of the CRT. A critical factor in the quality of this display is the type of "encoding" that is used in the TV camera to combine the signal together and the type of "decoding" that is used in the TV set to separate the signals back to RGB for display.
Comb filters are frequently used to improve the quality of a composite monitor, and devices using the Faroudja decoders are frequently considered the pinnacle of composite displays, at least for the NTSC market.
[edit] Early innovations of this technology
Originally, these monitors were used for commercial studios. Composite video first saw home use for dubbing tapes on VCRs. Also, one of the first stand-alone composite monitors for home use were on home computers. Notably, IBM PC compatibles, Apple II, Commodore VIC 20/64/128, Atari and other home computers of the 1980s had some composite monitors bundled with the systems; and some sold separately bearing the company nametags for the aforementioned computers. During that time period, home game consoles chose to stick with channel 3/4 outputs since many people had color televisions without composite video support. However, in 1985, the NES was released and was the first game console to feature direct composite outputs. As of today, some people still use stand-alone composite monitors with modern game consoles even with the advent of televisions with a tuner and composite inputs combined.
[edit] Problems to overcome
Nowadays, AV devices with advanced technology don't have Channel 3/4 outputs (e.g. DVD players, video game consoles, etc.). One major exception to this is a TiVo DVR. People often use RF modulators to overcome the problem of a TV set not having composite or S-Video inputs. Another method used by some game systems is a built-in RF converter, which eliminates the bulkiness of an RF modulator.
Sometimes, stand-alone composite monitors cannot be used with older-type game systems (e.g. Atari 2600, NES 2, etc.) that have only channel 3/4 outputs for conventional TVs, without modifying the systems themselves. A VCR can often be used to overcome that problem, since most VCRs have TV tuners built in.
These problems could explain why most composite monitors marketed to consumers also have TV-tuner capability.
[edit] Commercial use of composite monitors
Often, video studios will use stand-alone composite monitors since people there don't watch much TV. They can also be used when new AV devices are being tested. Stand-alone composite monitors are commonly used for video surveillance.
The monitors used in video surveillance often operate at the same frequencies as composite monitors but are not true composite monitors, as they use black and white graphics so the manufacture cost for the item will go down. Stand-alone composite monitors that are marketed as surveillance monitors are occasionally marketed for home use; The source by Circuit City is a notable retailer for that kind of scenario.
[edit] Common features
- Stereo sound
- TV tuner
- front AV inputs
- S-Video input
[edit] Examples of non-composites
Examples of non-composite video include
- RGB video (3 signals - Red, Green and Blue - on three wires typically from a computer)
- Component Video (3 signals - such as YUV or Y, B-Y, R-Y) that are used with professional video gear such as a Betacam VTR and some DVD players)
- S-Video (2 signals - which have all of the brightness information on one cable and all of the color information on another; however, almost all monitors with S-Video inputs also feature composite inputs)
- Digital Video (many different flavors)
