NTSC , named National Television System Committee , is an analog color television system used in North America from 1954 and up to digital conversion, used in most parts of America (except Brazil, Argentina, Paraguay, Uruguay, and French Guiana); Myanmar; South Korea; Taiwan; Philippines, Japan; and some Pacific Island countries and territories (see map).
The first NTSC standard was developed in 1941 and has no provision for color. In 1953 the second NTSC standard was adopted, allowing for color television broadcasting compatible with the existing black-and-white receiver stock. NTSC is the first widely adopted broadcast color system and remained dominant until the 2000s, when it began to be replaced with different digital standards such as ATSC and others.
Most countries that use the NTSC standard, as well as those using other analog television standards, have switched to, or are in the process of switching to newer digital television standards, at least four different standards are used worldwide. North America, parts of Central America, and South Korea adopt or have adopted ATSC standards, while other countries (like Japan) adopt or have adopted other standards than ATSC. After almost 70 years, the majority of over-the-air NTSC transmissions in the United States ceased on January 1, 2010, and on August 31, 2011 in Canada and most other NTSC markets. The majority of NTSC transmissions end in Japan on July 24, 2011, with Japanese prefectures Iwate, Miyagi, and Fukushima ending next year. Following a pilot program in 2013, most of Mexico's most powerful analogue stations leave the air on ten dates by 2015, with some 500 low-power stations and repeaters allowed to remain analog until the end of 2016. Digital broadcasting allows for higher resolution televisions, but digital standard definition television continues to use the image frequency and number of resolution lines set by the analog NTSC standard.
Video NTSC
Histori
The National Television Systems Committee was established in 1940 by the United States Federal Communications Commission (FCC) to resolve conflicts made between companies during the introduction of the national analog television system in the United States. In March 1941, the committee issued technical standards for black and white television built on a 1936 recommendation made by the Radio Manufacturers Association (RMA). Technical advances in vestigial side band techniques allow the opportunity to improve image resolution. NTSC selected 525 scan lines as a compromise between standard 441-scan RCA lines (already used by NBC TV RCA networks) and Philco and DuMont's desire to increase the number of scan lines between 605 and 800. This standard recommends the frame rate of 30 frames per second , which consists of two interlaced fields per frame at 262.5 lines per field and 60 fields per second. Other standards in the final recommendation are the 4: 3 aspect ratio, and the frequency modulation (FM) for the sound signal (which is quite new at the time).
In January 1950, the committee was re-established to standardize color television. The FCC has briefly approved the color television standard in October 1950 developed by CBS. The CBS system is not compatible with existing black-and-white receivers. It uses a rotating color wheel, reduces the number of scan lines from 525 to 405, and increases the field rate from 60 to 144, but has an effective frame rate of only 24 frames per second. Legal action by RCA rivals continued to use commercial systems from the air until June 1951, and regular broadcasts lasted only a few months before the manufacture of all color television sets banned by the Office of Defense Mobilization in October, ostensibly because of the Korean War. CBS canceled its system in March 1953, and the FCC replaced it on December 17, 1953, with NTSC color standards, co-operatively developed by several companies, including RCA and Philco.
In December 1953, the FCC unanimously approved what is now called the NTSC color television standard (later defined as RS-170a). The compatible color standards retain full backward compatibility with existing black-and-white television sets. Color information is added to a black-and-white image by introducing a precise color subcarrier of 315/88 MHz (usually described as 3.579545 MHz or 3.58 MHz). The exact frequency is chosen so that the horizontal line rate modulation component of the chrominance signal falls right between the horizontal line tariff modulation components of the lumination signal, allowing the chrominance signal to be filtered out of the lumination signal by a small degradation of the lumination signal. Due to the limitations of the frequency-dividing circuit at the time when color standards are applied, the frequency of the color subcarrier is constructed as a composite frequency collected from small integers, in this case 5ÃÆ' â € "9/(8ÃÆ'â € 11) Ã, MHz. The horizontal line level is reduced to about 15,734 rows per second (3,579545ÃÆ' â € "2/455Ã, MHz = 9/572Ã, MHz) of 15,750 rows per second, and the frame rate is reduced to 30/1,001? 29,970 frames per second (horizontal line level divided by 525 lines/frames) of 30 frames per second. This change amounted to 0.1 percent and is easily tolerated by existing television receivers.
The first publicly announced network broadcast of a program using NTSC's "compatible color system" was an episode of NBC Kukla, Fran and Ollie on August 30, 1953, though it can only be seen in color alone in the network headquarters. The first national NTSC color display comes on January 1, along with the coast-to-coast broadcast of the Roses Parade Tournament, can be seen on color prototype receivers at special presentations across the country. The first color NTSC television camera was the RCA TK-40, which was used for experimental broadcasts in 1953; an improved version, TK-40A, introduced in March 1954, was the first commercially available color television camera. Later that year, the upgraded TK-41 became the standard camera used during the 1960s.
The NTSC standard has been adopted by other countries, including most of America and Japan.
With the advent of digital television, analog broadcasts are being removed. Most US NTSC broadcasters were requested by the FCC to turn off their analog transmitters in 2009. Low-power stations, Class A stations and translators are required to close by 2015.
Maps NTSC
Technical details
Row and refresh rate
The NTSC color coding is used with the System M television signal, which consists of 30 / 1,001 (about 29.97) Ã, interlaced video frames per second. Each frame consists of two fields, each consisting of 262.5 scan lines, with a total of 525 scan lines. The 483 scan line forms a visible raster. The rest (vertical blanking interval) allows for vertical sync and retrace. This discharge interval was originally designed to simply empty the receiver CRT to allow simple analog circuits and slow vertical retrace of early TV receivers. However, some of these lines can now contain other data such as closed captioning and vertical interval timecode (VITC). In a complete raster (ignoring half rows due to interlacing) even line scanning (even every other line even calculated in video signals, eg {2, 4, 6,..., 524}) is drawn in the first field, and odd numbered (each another line that would be strange if it is counted in the video signal, for example {1, 3, 5,..., 525}) is drawn in the second field, to generate flicker-free image at refresh field frequency 60 / 1,001 Ã, Hz (about 59.94 Hz). In comparison, 576i systems such as PAL-B/G and SECAM use 625 lines (576 visible), and have higher vertical resolution, but lower temporal resolution of 25 frames or 50 fields per second.
The refresh rate of the NTSC field in a black-and-white system initially matches exactly the 60 Hz frequency of the alternating current used in the United States. Matching the field refresh rate to a power source avoids intermodulation (also called beat ), which results in the scrolling bar on the screen. The refresh rate sync to power that accidentally helps the kinescope camera record early live television broadcasts, as it is very easy to synchronize the film camera to capture a video frame on every movie frame by using alternating current frequency to adjust the speed of the synchronous AC drive motor cameras. When the colors are added to the system, the refresh frequency shifts slightly down by 0.1% to about 59.94 Hz to remove the stationary point pattern in the frequency difference between the sound carrier and the color, as described below in "Color encoding". As the frame rate changes to accommodate the color, it's almost as easy to trigger the camera shutter from the video signal itself.
The actual number of 525 lines was chosen as a consequence of the limitations of vacuum tube-based technology on that day. In early TV systems, the main voltage-controlled oscillator is run at twice the horizontal line frequency, and this frequency is divided down by the number of lines used (in this case 525) to give the field frequency (60 Hz in this case). This frequency is then compared to the 60 Hz power line frequency and each difference is corrected by adjusting the parent oscillator frequency. For interlaced scanning, an odd number of lines per frame is required to create identical vertical retrace spacing for odd and even planes, which means the oscillator frequency of the master must be divided down by odd numbers. At that time, the only practical method of frequency division was the use of vacuum tube multivibrators chain, the overall division ratio being the mathematical product of the chain division ratio. Since all odd number factors must also be odd numbers, then all the dividers in the chain must also be divided by odd numbers, and this should be relatively small due to thermal deviation problems with a vacuum tube device.. The closest practical sequence to the 500 that satisfies this criterion is 3ÃÆ' â € "5ÃÆ' â €" 5ÃÆ' â € "7 = 525 . (For the same reason, 625-line PAL-B/G and SECAM use 5ÃÆ' â € "5ÃÆ' â €" 5ÃÆ' â € "5 , the old 405-line British system uses 3ÃÆ' â "3ÃÆ' â €" 3ÃÆ' â € "3ÃÆ' â €" 5 , the French 819 line system uses 3ÃÆ' â € "3ÃÆ' â €" 7ÃÆ' â € "13 etc.)
Colorimetry
The original NTSC 1953 color specification, still part of the United States Federal Regulatory Code, defines the colorimetric values ​​of the system as follows:
Early color TV receivers, such as the RCA CT-100, are loyal to this specification (which is based on applicable film standards), having a larger gamut than most of today's monitors. Low efficiency phosphors (especially in Red) are weak and long lasting, leaving traces after moving objects. Beginning in the late 1950s, the phosphor picture tube would sacrifice saturation for increased brightness; this deviation from the standard on receivers and broadcasters is a source of considerable color variations.
SMPTE C
To ensure a more uniform color reproduction, the receiver begins to incorporate a series of color corrections that alter the received signal - encoded for the colorimetric values ​​listed above - into signals encoded for the phosphor really used. in the monitor. Since such color correction can not be accurately applied to transmitted nonlinear gamma correction signals, adjustments can only be estimated, incorporating color errors and luminance for very saturated colors.
Similarly, at the broadcaster stage, in 1968-69 Conrac Corp., which works with RCA, defines a set of controlled phosphors for use in broadcast color video image monitors. This specification survives today as a phosphor specification SMPTE "C" :
As with home receivers, it is further recommended that studio monitors combine the same color correction circuit so that the broadcaster will send the encoded image to original colorimetric values ​​of 1953, in accordance with FCC standards.
In 1987, the Society of Motion Picture and Television Engineers (SMPTE) Committee on Television Technology, Working Group on Colorimetry Monitor Studio , adopted the SMPTE C (Conrac) phosphor for general use in the Recommended Practice 145, manufacturers modify their camera designs to directly encode for SMPTE "C" colorimetry without color correction, as approved in the SMPTE standard 170M, "Composite Analog Video Signal - NTSC for Studio Applications" (1994). As a result, the ATSC digital television standard states that for 480i signals, SMPTE "C" colorimetry should be assumed unless colorimetric data is included in the transport flow.
NTSC Japan never changed the introduction and whitepoint to SMPTE "C", continued to use 1959 NTSC primary and whitepoint. Both the PAL and SECAM systems used native 1953 NTSC cadmintry until 1970; unlike the NTSC, however, the European Broadcasting Union (EBU) rejected the color corrections in the recipients and studio monitors that year and instead explicitly called for all equipment to directly encode signals for colorimetric values ​​"EBU", further enhancing the colorfulness of the system.
Color coding
For backward compatibility with black-and-white televisions, the NTSC uses a chromium-illuminated coding system invented in 1938 by Valence Georges. The three color of the signal image is divided into Luminance (derived mathematically from three separate color signals (Red, Green and Blue)) that take the place of the original monochrome signal and Chrominance which only carries > color information. This process is applied to any color source by the Colorplexer itself, thus enabling compatible color sources to be managed as if it were a regular monochrome source. This allows the black-and-white receiver to display the NTSC color signal by simply ignoring the chrominance signal. Some black-and-white TVs sold in the US after the introduction of color broadcasting in 1953 were designed to filter chroma, but the initial set of B & W does not do this and chrominance can be seen as a 'dot pattern' in highly colored areas of the image.
In NTSC, chrominance is encoded using two color signals known as I (in phase) and Q (in quadrature) in a process called QAM. The two signals each amplitude modulate the 3.58 MHz carrier which is 90 degrees out of phase with each other and the results are added together but with the operator itself suppressed. The result can be seen as a single sine wave with varying phases relative to the reference carrier and with various amplitudes. The varying phases represent the color instantaneous captured by the TV camera, and the amplitudes represent the momentary color saturation . The 3.58 MHz subcarrier is then added to Luminance to form a 'composite color signal' that modulates the video signal carrier as in monochrome transmissions.
For color TVs to recover color information from subcarrier colors, it must have zero phase references to replace previously pressed operators. The NTSC signal includes a short sample of this reference signal, known as the colorburst, located on the 'back porch' of each horizontal sync pulse. Color bursts consist of a minimum of eight non-fixed color subcarrier cycles (fixed phase and amplitude). The TV receiver has a "local oscillator", synchronized with these color bursts. Combining these reference phase signals comes from color bursts with amplitude and phase chrominance signals allowing recovery of 'I' and 'Q' signals which when combined with Luminance information allows reconstruction of color images on the screen. Color TV has been said to really be the color of the TV because of the total separation of the brightness part of the image from the color portion. On CRT television, the NTSC signal is converted into three color signals called R ed, G reen and B lue, each controlling the color electron.. TV sets with digital circuits use sampling techniques to process the signal but the end result is the same. For analog and digital circuits processing analog NTSC signals, three original color signals (Red, Green and Blue) are transmitted using three discrete signals (Luminance, I and Q) and then recovered as three separate colors and combined as color images.
When the transmitter broadcasts the NTSC signal, it amplitude-modulates the radio frequency carrier with the NTSC signal just described, while the frequency-modulate the 4.5 MHz carrier is higher with the audio signal. If a non-linear distortion occurs on a broadcast signal, the 3.579545 MHz color carrier may defeat with a sound carrier to produce a dot pattern on the screen. To make the resulting pattern less noticeable, the designer adjusts the original 15.750 Hz scanline rate down by a factor of 1,001 (0.1%) to match the audio carrier frequency divided by a factor of 286, resulting in a field rate of about 59.94 Hz. This adjustment ensures that the difference between the sound carrier and the color subcarrier (the most problematic intermodulation product of the two operators) is an odd multiple of half the rate of the line, which is a necessary condition for the points on successive lines being the opposite of the phase, making them at least visible.
The rate of 59.94 comes from the following calculations. The designer chooses to make the chrominance subcarrier frequency as n 0.5 multiple of the line frequency to minimize the interference between the luminance signal and the chrominance signal. (Another way this is often stated is that the frequency of the color subcarrier is an odd multiple of half the frequency of the line.) They then choose to create an audio subcarrier frequency which is an integer multiple of the line frequency to minimize intermodulation between the audio signal and the chrominance signal. The original black-and-white standard, with a 15.750 Hz line frequency and a 4.5 MHz audio subcarrier, does not meet this requirement, so designers must increase the audio subcarrier frequency or decrease line frequency. Lifting the audio subcarrier frequency prevents the recipient (black and white) from setting properly in the audio signal. Lowering the frequency of the line is relatively harmless, since the horizontal and vertical synchronization information in the NTSC signal allows the receiver to tolerate a large number of variations in line frequency. So the engineers choose the frequency of the line to be changed to the color standard. In the black-and-white standard, the frequency ratio of the audio subcarrier to the line frequency is 4.5Ã, MHz / 15,750Ã, Hz Ã, = 285, 71. In the standard color, this becomes integer to 286, which means the standard color line is 4.5Ã, MHz / 286 Ã,? 15.734 Hz. Maintaining the same number of scan lines per field (and frame), lower line rates should result in lower field rates. Splitting the 4500000 / 286 line per second with 262.5 lines per field generates about 59.94 fields per second.
Transmission modulation method
The transmitted NTSC television channel occupies a total bandwidth of 6 MHz. The actual video signal, which is amplitude modulated, is transmitted between 500 kHz and 5.45 MHz above the lower boundary of the channel. The video carrier is 1.25 MHz above the lower boundary of the channel. Like most AM signals, the video operator generates two sidebands, one above the operator and one below. The sidebands are 4.2 MHz wide. The entire upper sideband is transmitted, but only 1.25 MHz from the lower sideband, known as the vestigial sideband, is transmitted. The color subcarrier, as mentioned above, is 3.579545 MHz above the video carrier, and is modulated by quadrature-amplitude with a suppressed carrier. Audio signals are frequency-modulated, such as audio signals broadcast by FM radio stations in the 88-108 MHz frequency band, but with a maximum frequency deviation of 25 kHz, compared to 75 kHz as used on the FM band, making analog television audio signals sound quieter than FM radio signal as received on a broadband receiver. The main audio carrier is 4.5 MHz above the video carrier, making it 250 kHz below the top of the channel. Sometimes a channel can contain an MTS signal, which offers more than one audio signal by adding one or two subcarriers to the audio signal, each synchronized to a multiple of the line frequency. This usually happens when stereo audio and/or second audio program signals are used. The same extension is used in ATSC, where the ATSC digital carrier is broadcasted at 0.31 MHz above the lower boundary of the channel.
"Settings" is the offset voltage of 54 mV (7.5 IRE) between "black" and "empty" levels. It's unique to NTSC. CVBS stands for Color, Video, Blanking, and Sync.
Frame rate conversion
There is a big difference in the frame rate between movies, which runs at 24.0 frames per second, and the NTSC standard, which runs at about 29.97 (10 MHz-63/88/455/525) frames per second. In areas that use 25-fps television and video standards, this difference can be overcome by speeding up.
For the 30-fps standard, a process called "3: 2 pulldown" is used. One frame of the film is transmitted for three video areas (hold 1Ã,½ video frame), and the next frame is transmitted for two video areas (hold 1 frame of video). Two frame films are thus transmitted in five video areas, for an average of 2Ã,½ video fields per frame of film. The average frame rate is thus 60 ÃÆ' Â · 2.5 = 24 frames per second, so the average film speed is nominally what it should be. (In fact, for an hour of real time, 215,827.2 of the video area is displayed, representing 86,330.88 film frames, while within an hour of the actual 24-fps film projection, exactly the 86,400 frames are displayed: thus, 29.97 - fps NTSC 24-fps movie transmission runs at 99.92% of the film's normal speed.) Still-framing on playback can display video frames with the fields of two different movie frames, so any distinction between frames will appear as fast back flicker-and -advanced. There can also be seen jitter/"stutter" during slow camera pans (telecine judder).
To avoid 3: 2 pulldown, films recorded specifically for NTSC television are often taken on frame 30/s.
To display 25-fps materials (such as European television series and some European films) on NTSC equipment, each fifth frame is duplicated and then the resulting stream is intertwined.
Film capture for NTSC television at 24 frames per second is traditionally accelerated by 1/24 (about 104.17% of normal speed) for transmission in areas that use 25-fps television standards. This image rate increase is traditionally accompanied by a similar increase in audio tone and tempo. Recently, frame-blending has been used to convert 24 FPS videos to 25 FPS without changing the speed.
Movies filmed for television in an area that uses 25-fps television standards can be handled in one of two ways:
- This movie can be recorded at 24 frames per second. In this case, when transmitted in its home region, the film can be accelerated to 25 fps according to the analog techniques described above, or stored at 24 fps by the digital techniques described above. When the same movie is transmitted in an area that uses the 30-fps nominal television standard, there is no real change in speed, tempo, and tone.
- This movie can be recorded at 25 frames per second. In this case, when it is transmitted in its home region, the movie is displayed at normal speed, without changing the soundtrack that accompanies it. When the same film is shown in an area that uses the 30-fps nominal television standard, every fifth frame is duplicated, and there is still no real change in speed, tempo, and tone.
Since both film speeds have been used in the 25-fps area, viewers can face confusion about the true speed of video and audio, and the tone of voice, sound effects, and musical performances, in television movies from these areas. For example, they may wonder whether Jeremy Brett's Sherlock Holmes, made in the 1980s and early 1990s, was shot at 24 fps and then transmitted at an artificial speed in the 25-fps area, or whether it was shot in 25 fps original and then slowed to 24 fps for NTSC exhibition.
This difference is not only in television broadcasts over the air and through cable, but also in the home-video market, both on tape and disk, including laser discs and DVDs.
In digital television and video, replacing their analog predecessors, a single standard that can accommodate a wider range of image frequencies still shows the limits of analog regional standards. The ATSC standard, for example, allows frame rates of 23,976, 24, 29.97, 30, 59.94, and 60 frames per second, but not 25 and 50.
Modulation for analog satellite transmissions
Because satellite power is so limited, analog video transmissions via satellite differ from terrestrial TV transmissions. AM is a linear modulation method, so the demodulated signal-to-noise (SNR) ratio requires an equally high SNR of RF. SNR video quality studio more than 50 dB, so AM will need very high power and/or large antenna.
Wideband FM is used instead of trading RF bandwidth to reduce power. Increasing channel bandwidth from 6 to 36 MHz allows SNR RF only 10 dB or less. Wider noise bandwidth reduces this 40 dB energy savings by 36 MHz/6 MHz = 8 dB for a substantial net reduction of 32 dB.
Sound is on the FM subcarrier as in terrestrial transmission, but frequencies above 4.5 MHz are used to reduce aural/visual disturbance. 6.8, 5.8 and 6.2 MHz are commonly used. Stereo can be an audio signal and multiplex, discrete, or unrelated data can be placed on an additional subcarrier.
A triangular 60 Hz energy dispersion wave is added to the composite baseband signal (video plus audio and subcarrier data) before modulation. This limits the satellite's downlink power spectral density if the video signal is lost. Otherwise, the satellite may transmit all its forces at one frequency, interrupting the terrestrial microwave connection in the same frequency band.
In half transponder mode, frequency deviations from composite baseband signals are reduced by up to 18 MHz to allow other signals in the other half of the 36-MHz transponder. This reduces the benefits of FM, and the restored SNR diminishes because combined signal strength must be "backward" to avoid intermodulation distortions in satellite transponders. Single FM signal is a constant amplitude, so it can saturate transponders without distortion.
Order of columns
An NTSC "order" consists of an "even" field followed by a "weird" field. As far as reception of analog signals is concerned, this is purely a matter of convention and, it makes no difference. It's a bit like a dashed line that runs in the middle of the road, no matter whether it's a line/space pair or a space/line pair; the effect on the driver is exactly the same.
The introduction of the digital television format has changed many things. Most digital TV formats store and transmit fields in pairs as a single digital frame. Digital formats that match the NTSC field level, including popular DVD formats, video recording with the first event field in the digital frame, while the field-level format of the 625 line system often records videos with frames strange first . This means that when reproducing many non-NTSC-based digital formats, it is necessary to reverse the order of the field, otherwise an unacceptable "comb" effect occurs on the moving object as shown in front of one field and then jump back in the next field.
This is also a danger in which non-NTSC progressive videos are transcoded into interlaced and vice versa. Systems that recover progressive frames or transcoding videos must ensure that "Field Order" is observed, otherwise the recovered frame will consist of the plane of one frame and the plane of the adjacent frame, resulting in a linked "combed" artifact. This can often be observed in PC-based video utilities if an imprecise choice of de-interlacing algorithms is made.
For decades of high-power NTSC broadcasts in the United States, switching between two cameras' views was made according to two standards, a choice between the two made by geography, East versus West. In one area, a switch is made between a strange field that completes a single frame and an even field that initiates the next frame; on the other hand, the switch is made after the plane is flat and before the field is odd. So, for example, home VHS recordings made from local television news broadcasts in the East, when paused, will only show the view from one camera (unless there is dissolution or other multicamera intended), while VHS playback from a sitcom is recorded and edited in Los Angeles and then nationally transmitted can be paused when switching between cameras with half the line representing the outgoing shot and the other half describing the incoming shot.
Variant
NTSC-M
Unlike PAL, with the various underlying television broadcast systems used worldwide, NTSC color coding is almost always used with the broadcast system M , giving NTSC-M.
NTSC-N/NTSC50
NTSC-N/NTSC50 is an unofficial system that incorporates 625-line video with NTSC 3.58 MHz color. The PAL software running on NTSC Atari ST is displayed using this system because it can not display PAL color. Television sets and monitors with V-Hold knobs can display this system after adjusting the vertical grip.
NTSC-J
Only slightly different Japanese "NTSC-J" variants: in Japan, black levels and signal discharge levels are identical (at 0 IRE), because they are in PAL, while in NTSC America, black levels are slightly higher (7.5 IRE) rather than an empty level. Because the difference is quite small, a little change of the brightness key is all that's required to display another "NTSC" variant on each set as it should; most observers may not even notice the difference in the first place. Channel coding on NTSC-J is slightly different from NTSC-M. Specifically, the Japanese VHF band runs from channel 1-12 (located at a direct frequency above the Japanese FM radio band 76-90 MHz) while North American VHF TV bands use 2-13 channels (54-72 MHz, 76-88 MHz and 174-216 MHz) with 88-108 MHz is allocated for FM radio broadcasts. Japanese UHF TV channels are numbered from 13 upwards and not 14 upwards, but instead use the same UHF broadcasting frequencies as in North America. PAL-M (Brasil)
The Brazil PAL-M system, introduced on 19 February 1972, uses the same line/field as NTSC (525/60), and nearly equal bandwidth and scanning frequencies (15.750 vs. 15.734 kHz). Prior to color recognition, Brazil was broadcast in a standard black-and-white NTSC. As a result, the PAL-M signal is almost identical to North American NTSC signals, except for color subcarrier encoding (3.575611 MHz for PAL-M and 3.579545 MHz for NTSC). As a consequence of this close specification, PAL-M will be displayed in monochrome by voice on the NTSC set and vice versa.
- The PAL-M (PAL = Phase Alternating Line) specification is:
- Transmission of UHF/VHF bands,
- Frame rate 30
- Line/field 525/60
- Horizontal frequency. 15,750 kHz
- Vertical frequency. 60 Hz
- Sub operator colors 3.575611 MHz
- 4.2 MHz video bandwidth
- 4.5 MHz sound carrier frequency
- 6 MHz channel bandwidth
- The NTSC (National Television System Committee) specification is:
- Transmission band UHF/VHF
- Line/field 525/60
- Horizontal frequency 15.734 kHz
- Vertical frequency 59,939 Hz
- Frequency subcarrier color 3.579545 MHz
- 4.2 MHz video bandwidth
- 4.5 MHz sound carrier frequency
PAL-N
It is used in Argentina, Paraguay, and Uruguay. This is very similar to PAL-M (used in Brazil).
The NTSC-M and NTSC-N similarities can be seen in the ITU identification scheme table, reproduced here:
As shown, in addition to the number of lines and frames per second, the system is identical. NTSC-N/PAL-N is compatible with sources such as game consoles, VHS/Betamax VCR, and DVD players. However, they are not compatible with baseband broadcasts (received via antennas), although some newer sets come with NTSC 3.58 baseband support (NTSC 3.58 being the frequency for color modulation in NTSC: 3.58 MHz).
NTSC 4.43
In what can be considered the opposite of PAL-60, NTSC 4.43 is a pseudo color system that transmits NTSC encoding (525/29.97) with a 4.43 MHz color subcarrier instead of 3.58 MHz. The resulting output can only be viewed by a TV that supports the resulting pseudo-system (usually a multi-standard TV). Using the original NTSC TV to decode the signal does not produce color, while using PAL TV to decode the system produces erratic colors (observed less red and flashing randomly). This format was used by USAF TV based in Germany during the Cold War. It was also found as an optional output on some LaserDisc players and some game consoles sold on the market where the PAL system was used.
The NTSC 4.43 system, although not a broadcast format, most often appears as a PAL VCR cassette format playback function, starting with the Sony U-Matic 3-M format and then following the Betamax and VHS formats.Because Hollywood has a claim to provide software cassette tapes (movies and television series) for VCRs for world viewers, and since not all tapes are available in PAL format, the NTSC format cassette playback is highly desirable.
Multi-standard video monitors are already in use in Europe to accommodate broadcast sources in PAL, SECAM, and NTSC video formats. The heterodyne color-down process of U-Matic, Betamax & amp; VHS lends itself to small modifications of the VCR player to accommodate NTSC format cassettes. The color format-under VHS uses a 629 kHz subcarrier while U-Matic & amp; Betamax uses a 688-kHz subcarrier to carry chroma amplitude modulated signal for both NTSC and PAL formats. Since the VCR is ready to play the color portion of the NTSC recording using the PAL color mode, the PAL scanner and roller speed must be adjusted from field level 50 Hz PAL to NTSC's 59.94 Hz field level, and faster linear tape speed.
Changes to VCR PAL are very small thanks to the existing VCR recording formats. The output of the VCR when playing NTSC cassette in NTSC 4.43 mode is 525 lines/29.97 frames per second with PAL heterodyned compatible color. The multi-standard receiver is set to support NTSC H & amp; V frequency; it only needs to be done when receiving PAL color.
The existence of this multi-standard receiver may be part of the drive for DVD region coding. Since the color signal is a component on the disk for all display formats, almost no change is required for the PAL DVD player to play NTSC discs (525/29.97) as long as the screen is compatible with frame-rate.
OSKM
In January 1960 (7 years before the adoption of a modified SECAM version), experimental TV studios in Moscow began broadcasting using the OSKM system. The OSKM stands for "Simultaneous system with quadrature modulation" (Russian language ??????????????????????????????????????????????????????????????????????????????????????????? ??????????????????????????????????????????????????????????????????? ?). This used a color coding scheme which is then used in PAL (U and V instead of I and Q), as it is based on standard monochrome D/K, 625/50.
The color subcarrier frequency is 4.4296875 MHz and the signal bandwidth U and V approaches 1.5 MHz. Only about 4,000 TV sets of 4 models (Raduga, Temp-22, Izumrud-201 and Izumrud-203) were produced to study the real quality of TV reception. This TV is not commercially available, although it is included in the catalog of goods for the Soviet Union trade network.
The broadcasting with this system lasted about 3 years and stopped well before the transmission of SECAM began in the Soviet Union. None of the current multi-standard TV receivers can support this TV system.
NTSC-movie
Konten film umumnya diambil pada 24 frame/s dapat dikonversi menjadi 30 frame/s melalui proses telecine untuk menggandakan frame yang diperlukan.
Mathematically for NTSC this is relatively simple because you only need to duplicate every 4th frame. Various techniques are used. NTSC with actual frame rate 24 / 1,001 (about 23,976) Ã, frame/s is often defined as NTSC-movie. A process known as pullup, also known as pulldown, produces a frame that is duplicated during playback. This method is common for H.262/MPEG-2 Part 2 digital video so that original content is preserved and played back on equipment that can display it or can be converted for equipment that can not. Canada Canadian/USA video game area
Sometimes NTSC-US or NTSC-U/C is used to describe video game areas in North America (U/C refers to US Canada), as regional locking usually restricts games released in a region to that region.
Comparative quality
The reception problem can decrease the NTSC image by changing the phase of the color signal (actually the distortion of the differential phase), so that the color balance of the image will be changed unless compensation is made at the receiver. The electronic vacuum tube used in television during the 1960s caused various technical problems. Among other things, the color rupture phase often drift when the channel is changed, which is why NTSC television comes with color control. PAL and SECAM televisions do not need it, and although still found in NTSC TVs, color shifts in general are no longer a problem for more modern circuits in the 1970s. Compared with PAL in particular, NTSC color accuracy and consistency are sometimes considered lower, leading to video professionals and television engineers jokingly referring to NTSC as Never The Same Color Never Twice the Same Color , or No Real Skin Color , while for the more expensive PAL system, you need Pay for Luxury Additions . PAL has also been referred to as Peace At Last , Perfection At Last or Pictures Always Lovely in the color war. This is mostly applied to vacuum tube-based TVs, however, and the next solid state set model using Vertical Interval Reference signals has less difference in quality between NTSC and PAL. This color phase, "tint", or "hue" control allows anyone skilled in the art to easily calibrate the monitor with the SMPTE color rod, even with a set that has floated in its color representation, allowing the right color to display. The old PAL television sets were not equipped with user-accessible "hue" controls (factory installed), which contributed to its reputation for reproducible colors.
The use of NTSC color codes in S-Video system completely eliminates phase distortion. As a result, the use of NTSC color coding provides the highest resolution image quality (on the horizontal axis & frame rate) of three color systems when used with this scheme. (NTSC resolution on the vertical axis is lower than the European standard, 525 lines against 625.) However, it uses too much bandwidth for over-the-air transmission. Atari 800 and Commodore 64 home computers produce S-video, but only when used with a specially designed monitor because there are no TVs at that time that support separate chromas and luma on standard RCA jacks. In 1987, a standard 4-pin mini-DIN socket was introduced for S-video input with the introduction of the S-VHS player, which was the first device manufactured to use a 4-pin plug. However, S-VHS has never become so popular. The video game console in the 1990s began offering S-video output as well.
Incompatibility between 30 frames of NTSC per second and 24 frame films is resolved by a process that capitalizes on the field rate of an interlaced NTSC signal, thus avoiding the playback of films used for 576i systems at 25 frames per second (which causes audio accompanying little increase, sometimes fixed with the use of pitch shifter) with the price of some jerkiness in the video. See Conversion frame rate above.
Vertical interval reference
Standard NTSC video images contain several lines (lines 1-21 of each field) that are not visible (this is known as Vertical Blanking Interval, or VBI); all are beyond the edges of the viewable image, but only lines 1-9 are used for vertical sync pulses and equalizations. Remaining lines deliberately emptied in the original NTSC specification to allow time for the CRT-based electron beam to return to the top of the screen.
VIRs (or Vertical interval references), which were widely adopted in the 1980s, attempted to fix some color problems with NTSC video by adding reference data that studio included for luminance and chrominance levels on channel 19. A well-equipped television set later can use this data to customize the display to get closer to the original studio image. The actual VIR signal contains three parts, the first having 70 percent luminance and the same chrominance with a burst color signal, and the other two having 50 percent and 7.5 percent luminance respectively.
The successor not used for VIR, GCR, also adds the ability of multipath interference.
The remaining vertical blanking interval lines are typically used for datacasting or additional data such as video editing timestamps (vertex timecode timecode or SMPTE timecode on lines 12-14), test data on lines 17-18, network source code on line 20 and closed captioning, XDS and V-chip data on line 21. Early teletext applications also use vertical blanket interval lines 14-18 and 20, but teletext via NTSC has never been widely adopted by viewers.
Many stations are sending TV Guide On Screen (TVGOS) data to electronic program guide on the VBI line. The main station in the market will broadcast 4 lines of data, and the backup station will broadcast 1 line. In most markets, PBS stations are the primary host. TVGOS data can occupy every line from 10-25, but in practice is limited to 11-18, 20 and line 22. Line 22 is only used for 2 broadcasts, DirecTV and CFPL-TV.
TiVo data is also transmitted to some advertising and advertising programs so that customers can autorecord the advertised program, and also be used in paid half-hour paid programs on Ion Television and Discovery Channel that highlight TiVo's promotions and advertisers.
Countries and regions that used or used NTSC
Under countries and territories currently using or using the NTSC system. Many of these have switched or are currently switching from NTSC to digital television standards such as ATSC (USA, Canada, Mexico, Suriname, South Korea), ISDB (Japan, Philippines and parts of South America), DVB-T (Taiwan, Panama, Colombia and Trinidad and Tobago) or DTMB (Cuba).
Experimenting
Brazil (Between 1962 and 1963, Rede Tupi and Rede Excelsior made the first unofficial transmission in color, in special programs in the city of Sao Paulo, before the official adoption of PAL- M by the Brazilian Government on 19 February 1972)Countries and territories that have stopped using NTSC
The following countries no longer use NTSC for terrestrial broadcasting.
See also
- Television broadcast system
- Standard of Advanced Television Systems Committee
- BTSC
- NTSC-J
- NTSC-C
- PAL
- RCA
- SECAM
- List of common resolutions - Television
- List of video connectors
- Move image format
- The oldest television station
- The frequency of television channels
- The frequency is very high
- The frequency is very high
- Knife edge effect
- Channel 1 (North American TV)
- Channel 37
- North American television broadcasting frequency
- North American cable television frequency
- Australasia TV frequency
- Safe-broadcast
- Transition of digital television in the United States
- Glossary of terms
Note
References
- The standard defines the NTSC system published by the International Telecommunication Union in 1998 under the title "ITU-R BT.470-7 Recommendation, Conventional Analog Television System". It is publicly available on the Internet at ITU-R BT.470-7 or can be purchased from ITU.
- Ed Reitan (1997). Color System of CBS Field Arrangement.
External links
- National Television System Committee
- the frequency of US television channels
- Commercial Television Frequency - on TVTower.com
- NTSC refresh rate representation on television and on DVD
- Why 59.94 vs 60 Hz
Source of the article : Wikipedia
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