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Testcard
A test card, also known as a test pattern or start-up/closedown test, is a television test signal, typically broadcast at times when the transmitter is active but no program is being broadcast (often at sign-on and sign-off). Used since the earliest TV broadcasts, test cards were originally physical cards at which a television camera was pointed, allowing for simple adjustments of picture quality. Such cards are still often used for calibration, alignment, and matching of cameras and camcorders. From the 1950s, test card images were built into monoscope tubes which freed up the use of TV cameras which would otherwise have to be rotated to continuously broadcast physical test cards during downtime hours. Electronically generated test patterns, used for calibrating or troubleshooting the downstream signal path, were introduced in the late-1960s. These are generated by test signal generators, which do not depend on the correct configuration (and presence) of a camera, and can also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philips PM5544
The Philips PM5544 is a television pattern generator, most commonly used to provide a television station with a complex test card commonly referred to as a Philips Pattern or PTV Circle pattern. The content and layout of the pattern was designed by Danish engineer Finn Hendil ( da; 1939–2011) in the Philips TV & Test Equipment laboratory in Brøndby Municipality near Copenhagen under supervision of chief engineer Erik Helmer Nielsen in 1966–67. The equipment, the PM5544 Test Pattern Generator, which generates the pattern, was made by engineer Finn Hendil and his group in 1968–69. The same team would also develop the Spanish TVE colour test card in 1973. Since the widespread introduction of the PM5544 from the early-1970s, the Philips Pattern has become one of the most commonly used test cards, with only the SMPTE and EBU colour bars as well as the BBC's Test Card F coming close to its usage. The Philips PM5544 pattern was later incorporated into other test pattern generato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sign-on And Sign-off
A sign-on (or start-up in Commonwealth countries except Canada) is the beginning of operations for a radio or television station, generally at the start of each day. It is the opposite of a sign-off (or closedown in Commonwealth countries except Canada), which is the sequence of operations involved when a radio or television station shuts down its transmitters and goes off the air for a predetermined period; generally, this occurs during the overnight hours although a broadcaster's digital specialty or sub-channels may sign-on and sign-off at significantly different times as its main channels. Like other television programming, sign-on and sign-off sequences can be initiated by a broadcast automation system, and automatic transmission systems can turn the carrier signal and transmitter on/off by remote control. Sign-on and sign-off sequences have become less common due to the increasing prevalence of 24-hour-a-day, seven-day-a-week broadcasting. However, some national broadca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SMPTE Color Bars
SMPTE color bars are a television test pattern used where the NTSC video standard is utilized, including countries in North America. The Society of Motion Picture and Television Engineers (SMPTE) refers to the pattern as Engineering Guideline (EG) 1-1990. Its components are a known standard, and created by test pattern generators. Comparing it as received to the known standard gives video engineers an indication of how an NTSC video signal has been altered by recording or transmission and what adjustments must be made to bring it back to specification. It is also used for setting a television monitor or receiver to reproduce NTSC chrominance and luminance information correctly. A precursor to the SMPTE test pattern was conceived by Norbert D. Larky (1927–2018) and David D. Holmes (1926–2006) of RCA Laboratories and first published in RCA Licensee Bulletin LB-819 on February 7, 1951. U.S. patent 2,742,525 Color Test Pattern Generator (now expired) was awarded on April 17, 195 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Popular Music
Popular music is music with wide appeal that is typically distributed to large audiences through the music industry. These forms and styles can be enjoyed and performed by people with little or no musical training.Popular Music. (2015). ''Funk & Wagnalls New World Encyclopedia'' It stands in contrast to both art music and traditional or "folk" music. Art music was historically disseminated through the performances of written music, although since the beginning of the recording industry, it is also disseminated through recordings. Traditional music forms such as early blues songs or hymns were passed along orally, or to smaller, local audiences. The original application of the term is to music of the 1880s Tin Pan Alley period in the United States. Although popular music sometimes is known as "pop music", the two terms are not interchangeable. Popular music is a generic term for a wide variety of genres of music that appeal to the tastes of a large segment of the population, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indian Head Test Pattern With Labels
Indian or Indians may refer to: Peoples South Asia * Indian people, people of Indian nationality, or people who have an Indian ancestor ** Non-resident Indian, a citizen of India who has temporarily emigrated to another country * South Asian ethnic groups, referring to people of the Indian subcontinent, as well as the greater South Asia region prior to the 1947 partition of India * Anglo-Indians, people with mixed Indian and British ancestry, or people of British descent born or living in the Indian subcontinent * East Indians, a Christian community in India Europe * British Indians, British people of Indian origin The Americas * Indo-Canadians, Canadian people of Indian origin * Indian Americans, American people of Indian origin * Indigenous peoples of the Americas, the pre-Columbian inhabitants of the Americas and their descendants ** Plains Indians, the common name for the Native Americans who lived on the Great Plains of North America ** Native Americans in the U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Display Resolution
The display resolution or display modes of a digital television, computer monitor or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by different factors in cathode ray tube (CRT) displays, flat-panel displays (including liquid-crystal displays) and projection displays using fixed picture-element (pixel) arrays. It is usually quoted as ', with the units in pixels: for example, ' means the width is 1024 pixels and the height is 768 pixels. This example would normally be spoken as "ten twenty-four by seven sixty-eight" or "ten twenty-four by seven six eight". One use of the term ''display resolution'' applies to fixed-pixel-array displays such as plasma display panels (PDP), liquid-crystal displays (LCD), Digital Light Processing (DLP) projectors, OLED displays, and similar technologies, and is simply the physical number of columns and rows of pixels creating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overscan
Overscan is a behaviour in certain television sets, in which part of the input picture is shown outside of the visible bounds of the screen. It exists because cathode-ray tube (CRT) television sets from the 1930s through to the early 2000s were highly variable in how the video image was positioned within the borders of the screen. It then became common practice to have video signals with black edges around the picture, which the television was meant to discard in this way. Origins Early analog televisions varied in the displayed image because of manufacturing tolerance problems. There were also effects from the early design limitations of power supplies, whose DC voltage was not regulated as well as in later power supplies. This could cause the image size to change with normal variations in the AC line voltage, as well as a process called blooming, where the image size increased slightly when a brighter overall picture was displayed due to the increased electron beam current caus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Display Aspect Ratio
The aspect ratio of a display device is the proportional relationship between the width and the height of the display. It is expressed as two numbers separated by a colon (''x'':''y''), where ''x'' corresponds to the width and ''y'' to the height. Common aspect ratios for displays, past and present, include 5:4, 4:3, 16:10 and 16:9. Computer displays As of 2016, most computer monitors use widescreen displays with an aspect ratio of 16:9, although some portable PCs use narrower aspect ratios like 3:2 and 16:10 while some high-end desktop monitors have adopted ultrawide displays. The following table summarises the different aspect ratios that have been used in computer displays: † The resolution doesn't match the aspect ratio exactly, but is commonly marketed or described as such. History 4:3, 5:4 and 16:10 Until about 2003, most computer monitors used an aspect ratio of 4:3, and in some cases 5:4. For cathode ray tubes (CRT)s 4:3 was most common even in resolution ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colorburst
Colorburst is an analog video, composite video signal generated by a video-signal generator used to keep the chrominance subcarrier synchronized in a color television signal. By synchronizing an oscillator with the colorburst at the back porch (beginning) of each scan line, a television receiver is able to restore the suppressed carrier of the chrominance (color) signals, and in turn decode the color information. The most common use of colorburst is to genlock equipment together as a common reference with a vision mixer in a television studio using a multi-camera setup. Explanation In NTSC, its frequency is exactly 315/88 = 3.579 MHz with a phase of 180°. PAL uses a frequency of exactly 4.43361875 MHz, with its phase alternating between 135° and 225° from line to line. Since the colorburst signal has a known amplitude, it is sometimes used as a reference level when compensating for amplitude variations in the overall signal. SECAM is unique in not having ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IRE (unit)
The IRE unit is used in the measurement of composite video signals. Its name is derived from the initials of the Institute of Radio Engineers. A value of 100 IRE is defined to be +714 mV in an analog NTSC video signal. A value of 0 IRE corresponds to the voltage value of 0 mV, the signal value during the blanking period. The sync pulse is normally 40 IRE below this 0 IRE value, so the total range covered from peak to trough of an all white signal would be 140 IRE. Video signals use the "IRE" unit instead of DC voltages to describe levels and amplitudes. Based on a standard 1 Vpp NTSC composite-video signal that swings from -286 mV (sync tip) to +714 mV (peak video), a 140 IRE peak-to-peak convention is established. Thus, one NTSC IRE unit is 7.143 mV ( V or mV), where -40 IRE is equivalent to -285.7 mV, and +100 IRE is equivalent to +714.3 mV. 0 IRE is equivalent to 0 V. The black level is equivalent to 53.57 mV (7.5 IRE). The PAL video signal is slightly different in that it s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Video Projector
A video projector is an image projector that receives a video signalling (telecommunication), signal and projects the corresponding image on a projection screen using a lens (optics), lens system. Video projectors use a very bright ultra-high-performance lamp (a special mercury arc lamp), Xenon arc lamp, LED or solid state blue, RB, RGB or remote fiber optic RGB lasers to provide the illumination required to project the image, and most modern ones can correct any curves, blurriness, and other inconsistencies through manual settings. If a blue laser is used, a phosphor wheel is used to turn blue light into white light, which is also the case with white LEDs. (White LEDs do not use lasers.) A wheel is used in order to prolong the lifespan of the phosphor, as it is degraded by the heat generated by the laser diode. Remote fiber optic RGB laser racks can be placed far away from the projector, and several racks can be housed in a single, central room. Each projector can use up to two ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LED Display
A LED display is a flat panel display that uses an array of light-emitting diodes as pixels for a video display. Their brightness allows them to be used outdoors where they are visible in the sun for store signs and billboards. In recent years, they have also become commonly used in destination signs on public transport vehicles, as well as variable-message signs on highways. LED displays are capable of providing general illumination in addition to visual display, as when used for stage lighting or other decorative (as opposed to informational) purposes. LED displays can offer higher contrast ratios than a projector and are thus an alternative to traditional projection screens, and they can be used for large, uninterrupted (without a visible grid arising from the bezels of individual displays) video walls. microLED displays are LED displays with smaller LEDs, which poses significant development challenges. History Light-emitting diodes (LEDs) came into existence in 1962 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
