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91-453: A video floppy could store up to 25 frames either in the NTSC or PAL video standards, with each frame containing 2 fields of interlaced video . The video floppy also could store 50 frames of video, with each frame of video only containing one field of video information, recorded or played back in a " skip-field " fashion. Video floppies were first demonstrated by Sony and introduced under

182-500: A still-store system for stills & graphics for use in a television production, or for on-air slides used for station identification or during technical difficulties (such as a "Please Stand By" still). The video floppy was available as a data variant, which was sold as the Sony 2inch Data Disk PD-1 for use in its own PJ-100 "PRODUCE 100" word processor.The PRODUCE series began with the 100 and later included several other models, such as

273-540: A video camera , VCR , video capture card , or computer graphics output). Some VF recorders also had the feature of recording a couple of seconds of audio that accompanied each video frame. The recording media in a video floppy is a flexible magnetic disk 47 mm (1.9 in) in diameter and 40 μm (0.0016 in) thick. The disk is housed in a rectangular cartridge with one chamfered corner for orientation, measuring 60 mm × 54 mm × 3.6 mm (2.36 in × 2.13 in × 0.14 in);

364-537: A color subcarrier of precisely 315/88 MHz (usually described as 3.579545 MHz±10 Hz). The precise frequency was chosen so that horizontal line-rate modulation components of the chrominance signal fall exactly in between the horizontal line-rate modulation components of the luminance signal, such that the chrominance signal could easily be filtered out of the luminance signal on new television sets, and that it would be minimally visible in existing televisions. Due to limitations of frequency divider circuits at

455-457: A color image. When a transmitter broadcasts an NTSC signal, it amplitude-modulates a radio-frequency carrier with the NTSC signal just described, while it frequency-modulates a carrier 4.5 MHz higher with the audio signal. If non-linear distortion happens to the broadcast signal, the 3.579545 MHz color carrier may beat with the sound carrier to produce a dot pattern on the screen. To make

546-528: A consequence, the ATSC digital television standard states that for 480i signals, SMPTE C colorimetry should be assumed unless colorimetric data is included in the transport stream. Japanese NTSC never changed primaries and whitepoint to SMPTE C, continuing to use the 1953 NTSC primaries and whitepoint. Both the PAL and SECAM systems used the original 1953 NTSC colorimetry as well until 1970; unlike NTSC, however,

637-400: A doctor or a surgeon . A patient may be fully conscious or anaesthetised during the procedure. Most often, the term endoscopy is used to refer to an examination of the upper part of the gastrointestinal tract , known as an esophagogastroduodenoscopy . For nonmedical use, similar instruments are called borescopes . Adolf Kussmaul was fascinated by sword swallowers who would insert

728-425: A feeling of distention from the insufflated air that was used during the procedure. Both problems are mild and fleeting. When fully recovered, the patient will be instructed when to resume their usual diet (probably within a few hours) and will be allowed to be taken home. Where sedation has been used, most facilities mandate that the patient be taken home by another person and that they not drive or handle machinery for

819-493: A higher vertical resolution, but a lower temporal resolution of 25 frames or 50 fields per second. The NTSC field refresh frequency in the black-and-white system originally exactly matched the nominal 60 Hz frequency of alternating current power used in the United States. Matching the field refresh rate to the power source avoided intermodulation (also called beating ), which produces rolling bars on

910-480: A minimum of eight cycles of the unmodulated (pure original) color subcarrier. The TV receiver has a local oscillator, which is synchronized with these color bursts to create a reference signal. Combining this reference phase signal with the chrominance signal allows the recovery of the I ′ {\displaystyle I^{\prime }} and Q ′ {\displaystyle Q^{\prime }} signals, which in conjunction with

1001-428: A process called QAM . The I ′ Q ′ {\displaystyle I^{\prime }Q^{\prime }} color space is rotated relative to the difference signal color space, such that orange-blue color information (which the human eye is most sensitive to) is transmitted on the I ′ {\displaystyle I^{\prime }} signal at 1.3 MHz bandwidth, while

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1092-465: A program using the NTSC "compatible color" system was an episode of NBC's Kukla, Fran and Ollie on August 30, 1953, although it was viewable in color only at the network's headquarters. The first nationwide viewing of NTSC color came on the following January 1 with the coast-to-coast broadcast of the Tournament of Roses Parade , viewable on prototype color receivers at special presentations across

1183-535: A single field and includes three frequency-modulated waveforms: the luminance information, and red (R-Y) and blue (B-Y) color difference chrominance signals. Luminance is recorded between 6 MHz and 7.5 MHz (white peak); the R-Y signal has a center band of 1.2 MHz with a 0.7 MHz bandwidth and the B-Y signal has a center band of 1.3 MHz with a 0.5 MHz bandwidth. The Hi-Band format developed in 1988 shifts

1274-418: A sword down their throat without gagging. This drew inspiration to insert a hollow tube for observation; the next problem to solve was how to shine light through the tube, as they were still relying on candles and oil lamps as light sources. The term endoscope was first used on February 7, 1855, by engineer-optician Charles Chevalier, in reference to the uréthroscope of Désormeaux , who himself began using

1365-505: A tear of the stomach or esophagus lining and bleeding. Although perforation generally requires surgery, certain cases may be treated with antibiotics and intravenous fluids. Bleeding may occur at the site of a biopsy or polyp removal. Such typically minor bleeding may simply stop on its own or be controlled by cauterisation. Seldom does surgery become necessary. Perforation and bleeding are rare during gastroscopy. Other minor risks include drug reactions and complications related to other diseases

1456-475: A wideband 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 may contain an MTS signal, which offers more than one audio signal by adding one or two subcarriers on the audio signal, each synchronized to a multiple of the line frequency. This is normally the case when stereo audio and/or second audio program signals are used. The same extensions are used in ATSC , where

1547-488: Is 3.579545 MHz above the video carrier, and is quadrature-amplitude-modulated with a suppressed carrier. The audio signal is frequency-modulated , like the audio signals broadcast by FM radio stations in the 88–108 MHz band, but with a 25 kHz maximum frequency deviation , as opposed to 75 kHz as is used on the FM band , making analog television audio signals sound quieter than FM radio signals as received on

1638-432: Is 60 μm (0.0024 in) wide with a track-to-track pitch of 100 μm (0.0039 in); the second track is recorded inboard of the first at a radius of 19.9 mm (0.78 in), and so on until the 52nd track is encoded with a radius of 14.7 mm (0.58 in). Track 51 is reserved as blank (without information), and Track 52 is used for a control signal. The analog signal recorded to each track corresponds to

1729-476: Is a 4° gap to afford margin against overwriting the succeeding (or preceding) block, followed by a 1° interval reserved for a burst signal that states the recording density and indicates the disk is encoded with digital data. After the burst signal, a 64-bit index signal is used to record the data address (track and block information) along with a checksum signal. The remainder of the block is formatted into 128 distinct frames, each capable of recording 32 bytes, making

1820-401: Is a procedure used in medicine to look inside the body. The endoscopy procedure uses an endoscope to examine the interior of a hollow organ or cavity of the body. Unlike many other medical imaging techniques, endoscopes are inserted directly into the organ. There are many types of endoscopies. Depending on the site in the body and type of procedure, an endoscopy may be performed by either

1911-401: Is added to the composite baseband signal (video plus audio and data subcarriers) before modulation. This limits the satellite downlink power spectral density in case the video signal is lost. Otherwise the satellite might transmit all of its power on a single frequency, interfering with terrestrial microwave links in the same frequency band. In half transponder mode, the frequency deviation of

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2002-673: Is also used in diagnosis, most commonly by performing a biopsy to check for conditions such as anemia , bleeding, inflammation , and cancers of the digestive system . The procedure may also be used for treatment such as cauterization of a bleeding vessel, widening a narrow esophagus, clipping off a polyp or removing a foreign object. Specialty professional organizations that specialize in digestive problems advise that many patients with Barrett's esophagus receive endoscopies too frequently. Such societies recommend that patients with Barrett's esophagus and no cancer symptoms after two biopsies receive biopsies as indicated and no more often than

2093-411: Is composed of two fields, each consisting of 262.5 scan lines, for a total of 525 scan lines. The visible raster is made up of 486 scan lines. The later digital standard, Rec. 601 , only uses 480 of these lines for visible raster. The remainder (the vertical blanking interval ) allow for vertical synchronization and retrace. This blanking interval was originally designed to simply blank

2184-418: Is designed to excite only the corresponding red, green, or blue phosphor dots. TV sets with digital circuitry use sampling techniques to process the signals but the result is the same. For both analog and digital sets processing an analog NTSC signal, the original three color signals are transmitted using three discrete signals (Y, I and Q) and then recovered as three separate colors (R, G, and B) and presented as

2275-701: Is duplicated and then the resulting stream is interlaced. Film shot for NTSC television at 24 frames per second has traditionally been accelerated by 1/24 (to about 104.17% of normal speed) for transmission in regions that use 25-fps television standards. This increase in picture speed has traditionally been accompanied by a similar increase in the pitch and tempo of the audio. More recently, frame-blending has been used to convert 24 FPS video to 25 FPS without altering its speed. Film shot for television in regions that use 25-fps television standards can be handled in either of two ways: Because both film speeds have been used in 25-fps regions, viewers can face confusion about

2366-508: Is equivalent to NTSC is 720 × 480 pixels. The digital television (DTV) equivalent is 704 × 480 pixels. The National Television System Committee was established in 1940 by the United States Federal Communications Commission (FCC) to resolve the conflicts between companies over the introduction of a nationwide analog television system in the United States. In March 1941,

2457-443: Is severely limited, analog video transmission through satellites differs from terrestrial TV transmission. AM is a linear modulation method, so a given demodulated signal-to-noise ratio (SNR) requires an equally high received RF SNR. The SNR of studio quality video is over 50 dB, so AM would require prohibitively high powers and/or large antennas. Wideband FM is used instead to trade RF bandwidth for reduced power. Increasing

2548-622: Is sometimes called NTSC II. The only other broadcast television system to use NTSC color was the System J . Brazil used System M with PAL color. Vietnam, Cambodia and Laos used System M with SECAM color - Vietnam later started using PAL in the early 1990s. The NTSC/System M standard was used in most of the Americas (except Argentina , Brazil , Paraguay , and Uruguay ), Myanmar , South Korea , Taiwan , Philippines , Japan , and some Pacific Islands nations and territories (see map). Since

2639-628: Is transmitted for two video fields (lasting 1 video frame). Two film frames are thus transmitted in five video fields, for an average of 2 + 1 ⁄ 2  video fields per film frame. The average frame rate is thus 60 ÷ 2.5 = 24 frames per second, so the average film speed is nominally exactly what it should be. (In reality, over the course of an hour of real time, 215,827.2 video fields are displayed, representing 86,330.88 frames of film, while in an hour of true 24-fps film projection, exactly 86,400 frames are shown: thus, 29.97-fps NTSC transmission of 24-fps film runs at 99.92% of

2730-410: The Q ′ {\displaystyle Q^{\prime }} signal encodes purple-green color information at 0.4 MHz bandwidth; this allows the chrominance signal to use less overall bandwidth without noticeable color degradation. The two signals each amplitude modulate 3.58 MHz carriers which are 90 degrees out of phase with each other and the result added together but with

2821-516: The Y ′ {\displaystyle Y^{\prime }} signal, is reconstructed to the individual R ′ G ′ B ′ {\displaystyle R^{\prime }G^{\prime }B^{\prime }} signals, that are then sent to the CRT to form the image. In CRT televisions, the NTSC signal is turned into three color signals: red, green, and blue, each controlling an electron gun that

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2912-602: The Americas and Japan . With the advent of digital television , analog broadcasts were largely phased out. Most US NTSC broadcasters were required by the FCC to shut down their analog transmitters by February 17, 2009, however this was later moved to June 12, 2009. Low-power stations , Class A stations and translators were required to shut down by 2015, although an FCC extension allowed some of those stations operating on Channel 6 to operate until July 13, 2021. The remaining Canadian analog TV transmitters, in markets not subject to

3003-786: The Mavipak name in 1981 for their prototype Mavica (not to be confused with their later line of Mavica digital cameras introduced in the mid-1990s, which stored JPEG images to standard 3.5-inch floppy disks readable by computers instead). The video floppy specification was proposed by the Electronic Still Camera Conference in 1985 and established as Standard CP-3901 (formerly CPZ-250) of the Electronic Industries Association of Japan (EIAJ) in September 1988. The video floppy format

3094-497: The carriers themselves being suppressed . The result can be viewed as a single sine wave with varying phase relative to a reference carrier and with varying amplitude. The varying phase represents the instantaneous color hue captured by a TV camera, and the amplitude represents the instantaneous color saturation . The 3.579545 MHz subcarrier is then added to the Luminance to form the composite color signal which modulates

3185-508: The 200, 300, 1000, 575, and 2000. A similarly sized disk was also used by the Zenith MinisPort laptop computer from 1989, digitally formatted for data storage. The MinisPort could store up to 793 KB of information on 2-inch LT format disks called LT-1 . Video floppy and LT-1 are neither physically nor digitally compatible, so media can not be interchanged between drives using video floppy or LT standards. An enhanced version of

3276-562: The ATSC digital carrier is broadcast at 0.31 MHz above the lower bound of the channel. "Setup" is a 54 mV (7.5  IRE ) voltage offset between the "black" and "blanking" levels. It is unique to NTSC. CVBS stands for Color, Video, Blanking, and Sync. The following table shows the values for the basic RGB colors, encoded in NTSC There is a large difference in frame rate between film, which runs at 24 frames per second, and

3367-902: The European Broadcasting Union (EBU) rejected color correction in receivers and studio monitors that year and instead explicitly called for all equipment to directly encode signals for the "EBU" colorimetric values. In reference to the gamuts shown on the CIE chromaticity diagram (above), the variations between the different colorimetries can result in significant visual differences. To adjust for proper viewing requires gamut mapping via LUTs or additional color grading . SMPTE Recommended Practice RP 167-1995 refers to such an automatic correction as an "NTSC corrective display matrix." For instance, material prepared for 1953 NTSC may look desaturated when displayed on SMPTE C or ATSC/ BT.709 displays, and may also exhibit noticeable hue shifts. On

3458-431: The NTSC color standard, which was cooperatively 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 standard retained full backward compatibility with then-existing black-and-white television sets. Color information was added to the black-and-white image by introducing

3549-485: The NTSC standard, as well as those using other analog television standards , have switched to, or are in process of switching to, newer digital television standards, with there being at least four different standards in use around the world. North America, parts of Central America , and South Korea are adopting or have adopted the ATSC standards, while other countries, such as Japan , are adopting or have adopted other standards instead of ATSC. After nearly 70 years,

3640-402: The NTSC standard, which runs at approximately 29.97 (10 MHz×63/88/455/525) frames per second. In regions that use 25-fps television and video standards, this difference can be overcome by speed-up . For 30-fps standards, a process called " 3:2 pulldown " is used. One film frame is transmitted for three video fields (lasting 1 + 1 ⁄ 2  video frames), and the next frame

3731-464: The VF format called Hi-VF was introduced in the late 1980s, providing higher resolution per video still than its predecessor. It used higher-bandwidth video recording, much like S-VHS as compared to VHS , or Hi8 compared to Video 8 . NTSC NTSC (from National Television System Committee ) is the first American standard for analog television , published and adopted in 1941. In 1961, it

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3822-546: The air and through cable, but also in the home-video market, on both tape and disc, including laser disc and DVD . In digital television and video, which are replacing their analog predecessors, single standards that can accommodate a wider range of frame rates still show the limits of analog regional standards. The initial version of the ATSC standard, for example, allowed frame rates of 23.976, 24, 29.97, 30, 59.94, 60, 119.88 and 120 frames per second, but not 25 and 50. Modern ATSC allows 25 and 50 FPS. Because satellite power

3913-420: The audio subcarrier frequency or lower the line frequency. Raising the audio subcarrier frequency would prevent existing (black and white) receivers from properly tuning in the audio signal. Lowering the line frequency is comparatively innocuous, because the horizontal and vertical synchronization information in the NTSC signal allows a receiver to tolerate a substantial amount of variation in the line frequency. So

4004-426: The blue difference signal is B ′ − Y ′ {\displaystyle B^{\prime }-Y^{\prime }} . These difference signals are then used to derive two new color signals known as I ′ {\displaystyle I^{\prime }} (in-phase) and Q ′ {\displaystyle Q^{\prime }} (in quadrature) in

4095-448: The camera shutter from the video signal itself. The actual figure of 525 lines was chosen as a consequence of the limitations of the vacuum-tube-based technologies of the day. In early TV systems, a master voltage-controlled oscillator was run at twice the horizontal line frequency, and this frequency was divided down by the number of lines used (in this case 525) to give the field frequency (60 Hz in this case). This frequency

4186-427: The cartridge is equipped with a sliding shutter for dust protection and a hub opening that is 15.9 mm (0.63 in) in diameter. The magnetic disc is divided into 52 coaxial tracks and rotates at either 3600 RPM to match the NTSC video field frequency (60 fields/second) or 3000 RPM for PAL and SECAM (50 fields/second) instead. The first track is encoded with a radius of 20 mm (0.79 in); each track

4277-601: The channel bandwidth from 6 to 36 MHz allows a RF SNR of only 10 dB or less. The wider noise bandwidth reduces this 40 dB power saving by 36 MHz / 6 MHz = 8 dB for a substantial net reduction of 32 dB. Sound is on an FM subcarrier as in terrestrial transmission, but frequencies above 4.5 MHz are used to reduce aural/visual interference. 6.8, 5.8 and 6.2 MHz are commonly used. Stereo can be multiplex, discrete, or matrix and unrelated audio and data signals may be placed on additional subcarriers. A triangular 60 Hz energy dispersal waveform

4368-525: The chrominance signal. (Another way this is often stated is that the color subcarrier frequency is an odd multiple of half the line frequency.) They then chose to make the audio subcarrier frequency an integer multiple of the line frequency to minimize visible (intermodulation) interference between the audio signal and the chrominance signal. The original black-and-white standard, with its 15,750 Hz line frequency and 4.5 MHz audio subcarrier, does not meet these requirements, so designers had to either raise

4459-563: The committee issued a technical standard for black-and-white television that built upon a 1936 recommendation made by the Radio Manufacturers Association (RMA). Technical advancements of the vestigial side band technique allowed for the opportunity to increase the image resolution. The NTSC selected 525 scan lines as a compromise between RCA 's 441-scan line standard (already being used by RCA's NBC TV network) and Philco 's and DuMont 's desire to increase

4550-576: The committee was reconstituted to standardize color television . The FCC had briefly approved a 405-line field-sequential color television standard in October 1950, which was developed by CBS . The CBS system was incompatible with existing black-and-white receivers. It used a rotating color wheel, reduced the number of scan lines from 525 to 405, and increased the field rate from 60 to 144, but had an effective frame rate of only 24 frames per second. Legal action by rival RCA kept commercial use of

4641-509: The composite baseband signal is reduced to 18 MHz to allow another signal in the other half of the 36 MHz transponder. This reduces the FM benefit somewhat, and the recovered SNRs are further reduced because the combined signal power must be "backed off" to avoid intermodulation distortion in the satellite transponder. A single FM signal is constant amplitude, so it can saturate a transponder without distortion. Endoscopy An endoscopy

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4732-571: The country. The first color NTSC television camera was the RCA TK-40 , used for experimental broadcasts in 1953; an improved version, the TK-40A, introduced in March 1954, was the first commercially available color television camera. Later that year, the improved TK-41 became the standard camera used throughout much of the 1960s. The NTSC standard has been adopted by other countries, including some in

4823-480: The display, etc. Over its history, NTSC color had two distinctly defined colorimetries, shown on the accompanying chromaticity diagram as NTSC 1953 and SMPTE C. Manufacturers introduced a number of variations for technical, economic, marketing, and other reasons. The original 1953 color NTSC specification, still part of the United States Code of Federal Regulations , defined the colorimetric values of

4914-462: The early B&W sets did not do this and chrominance could be seen as a crawling dot pattern in areas of the picture that held saturated colors. To derive the separate signals containing only color information, the difference is determined between each color primary and the summed luma. Thus the red difference signal is R ′ − Y ′ {\displaystyle R^{\prime }-Y^{\prime }} and

5005-405: The electron beam of the receiver's CRT to allow for the simple analog circuits and slow vertical retrace of early TV receivers. However, some of these lines may now contain other data such as closed captioning and vertical interval timecode (VITC). In the complete raster (disregarding half lines due to interlacing ) the even-numbered scan lines (every other line that would be even if counted in

5096-424: The end of 2016. Digital broadcasting allows higher-resolution television , but digital standard definition television continues to use the frame rate and number of lines of resolution established by the analog NTSC standard. NTSC color encoding is used with the System M television signal, which consists of 30 ⁄ 1.001  (approximately 29.97)  interlaced frames of video per second . Each frame

5187-417: The engineers chose the line frequency to be changed for the color standard. In the black-and-white standard, the ratio of audio subcarrier frequency to line frequency is 4.5 MHz ⁄ 15,750 Hz  = 285.71. In the color standard, this becomes rounded to the integer 286, which means the color standard's line rate is 4.5 MHz ⁄ 286  ≈ 15,734 Hz. Maintaining

5278-549: The film's normal speed.) Still-framing on playback can display a video frame with fields from two different film frames, so any difference between the frames will appear as a rapid back-and-forth flicker. There can also be noticeable jitter/"stutter" during slow camera pans ( telecine judder ). Film shot specifically for NTSC television is usually taken at 30 (instead of 24) frames per second to avoid 3:2 pulldown. To show 25-fps material (such as European television series and some European movies) on NTSC equipment, every fifth frame

5369-562: The formatted capacity of the Video Floppy 800 Kbytes (50 tracks × 4 blocks/track × 128 frames/block × 32 bytes/frame). The video floppy was used in multiple applications during the 1980s and 1990s. Many medical endoscopy and dentistry video systems, as well as industrial video borescopes & fiberscopes , used VF disks for storing video images for later playback and study. Standalone VF recorders & players were also used by television stations and video production studios as

5460-513: The former term a month later. The self-illuminated endoscope was developed at Glasgow Royal Infirmary in Scotland (one of the first hospitals to have mains electricity) in 1894/5 by John Macintyre as part of his specialization in the investigation of the larynx. Endoscopy may be used to investigate symptoms in the digestive system including nausea , vomiting , abdominal pain , difficulty swallowing , and gastrointestinal bleeding . It

5551-531: The introduction of digital sources (ex: DVD) the term NTSC has been used to refer to digital formats with number of active lines between 480 and 487 having 30 or 29.97 frames per second rate, serving as a digital shorthand to System M. The so-called NTSC-Film standard has a digital standard resolution of 720 × 480 pixel for DVD-Videos , 480 × 480 pixel for Super Video CDs (SVCD, Aspect Ratio: 4:3) and 352 × 240 pixel for Video CDs (VCD). The digital video (DV) camcorder format that

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5642-427: The lower bound of the channel. The video carrier is 1.25 MHz above the lower bound of the channel. Like most AM signals, the video carrier generates two sidebands , one above the carrier and one below. The sidebands are each 4.2 MHz wide. The entire upper sideband is transmitted, but only 1.25 MHz of the lower sideband, known as a vestigial sideband , is transmitted. The color subcarrier, as noted above,

5733-455: The luminance signal to between 7.7 and 9.7 MHz, improving the signal-to-noise ratio and resolution. The patent for the data variant of the Video Floppy was filed by Ken Kutaragi and assigned to Sony Corporation . This patent describes a formatting scheme that allows the disk to record digital data. In this scheme, each track is divided into 4 angular sectors known as blocks, with each block spanning an angle of 90°. Within each block, there

5824-721: The majority of over-the-air NTSC transmissions in the United States ceased on June 12, 2009, and by August 31, 2011, in Canada and most other NTSC markets. The majority of NTSC transmissions ended in Japan on July 24, 2011, with the Japanese prefectures of Iwate , Miyagi , and Fukushima ending the next year. After a pilot program in 2013, most full-power analog stations in Mexico left the air on ten dates in 2015, with some 500 low-power and repeater stations allowed to remain in analog until

5915-466: The mandatory transition in 2011, were scheduled to be shut down by January 14, 2022, under a schedule published by Innovation, Science and Economic Development Canada in 2017; however the scheduled transition dates have already passed for several stations listed that continue to broadcast in analog (e.g. CFJC-TV Kamloops, which has not yet transitioned to digital, is listed as having been required to transition by November 20, 2020). Most countries using

6006-559: The nonlinear gamma corrected signals transmitted, the adjustment can only be approximated, introducing both hue and luminance errors for highly saturated colors. Similarly at the broadcaster stage, in 1968–69 the Conrac Corp., working with RCA, defined a set of controlled phosphors for use in broadcast color picture video monitors . This specification survives today as the SMPTE C phosphor specification: As with home receivers, it

6097-419: The number of scan lines to between 605 and 800. The standard recommended a frame rate of 30 frames (images) per second, consisting of two interlaced fields per frame at 262.5 lines per field and 60 fields per second. Other standards in the final recommendation were an aspect ratio of 4:3, and frequency modulation (FM) for the sound signal (which was quite new at the time). In January 1950,

6188-515: The only practical method of frequency division was the use of a chain of vacuum tube multivibrators , the overall division ratio being the mathematical product of the division ratios of the chain. Since all the factors of an odd number also have to be odd numbers, it follows that all the dividers in the chain also had to divide by odd numbers, and these had to be relatively small due to the problems of thermal drift with vacuum tube devices. The closest practical sequence to 500 that meets these criteria

6279-419: The original black-and-white system; when color was added to the system, however, the refresh frequency was shifted slightly downward by 0.1%, to approximately 59.94 Hz, to eliminate stationary dot patterns in the difference frequency between the sound and color carriers (as explained below in §   Color encoding ). By the time the frame rate changed to accommodate color, it was nearly as easy to trigger

6370-426: The other hand, SMPTE C materials may appear slightly more saturated on BT.709/sRGB displays, or significantly more saturated on P3 displays, if the appropriate gamut mapping is not performed. NTSC uses a luminance - chrominance encoding system, incorporating concepts invented in 1938 by Georges Valensi . Using a separate luminance signal maintained backward compatibility with black-and-white television sets in use at

6461-437: The patient may have. Consequently, patients should inform their doctor of all allergic tendencies and medical problems. Occasionally, the site of the sedative injection may become inflamed and tender for a short time. This is usually not serious and warm compresses for a few days are usually helpful. While any of these complications may possibly occur, each of them occurs quite infrequently. A doctor can further discuss risks with

6552-436: The patient with regard to the particular need for gastroscopy. After the procedure, the patient will be observed and monitored by a qualified individual in the endoscopy room, or a recovery area, until a significant portion of the medication has worn off. Occasionally the patient is left with a mild sore throat, which may respond to saline gargles, or chamomile tea. It may last for weeks or not happen at all. The patient may have

6643-407: The place of the original monochrome signal . The color difference information is encoded into the chrominance signal, which carries only the color information. This allows black-and-white receivers to display NTSC color signals by simply ignoring the chrominance signal. Some black-and-white TVs sold in the U.S. after the introduction of color broadcasting in 1953 were designed to filter chroma out, but

6734-541: The recommended rate. Health care providers can use endoscopy to review any of the following body parts: Endoscopy is used for many procedures: An endoscopy is a simple procedure that allows a doctor to look inside human bodies using an instrument called an endoscope. A cutting tool can be attached to the end of the endoscope, and the apparatus can then be used to perform minor procedures such as tissue biopsies, banding of oesophageal varices or removal of polyps. The main risks are infection, over-sedation, perforation, or

6825-400: The resulting pattern less noticeable, designers adjusted the original 15,750 Hz scanline rate down by a factor of 1.001 (0.1%) to match the audio carrier frequency divided by the factor 286, resulting in a field rate of approximately 59.94 Hz. This adjustment ensures that the difference between the sound carrier and the color subcarrier (the most problematic intermodulation product of

6916-441: The same number of scan lines per field (and frame), the lower line rate must yield a lower field rate. Dividing 4500000 ⁄ 286 lines per second by 262.5 lines per field gives approximately 59.94 fields per second. An NTSC television channel as transmitted 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

7007-415: The screen. Synchronization of the refresh rate to the power incidentally helped kinescope cameras record early live television broadcasts, as it was very simple to synchronize a film camera to capture one frame of video on each film frame by using the alternating current frequency to set the speed of the synchronous AC motor-drive camera. This, as mentioned, is how the NTSC field refresh frequency worked in

7098-436: The standard at both the receiver and broadcaster was the source of considerable color variation. To ensure more uniform color reproduction, some manufacturers incorporated color correction circuits into sets, that converted the received signal—encoded for the colorimetric values listed above—adjusting for the actual phosphor characteristics used within the monitor. Since such color correction can not be performed accurately on

7189-601: The system as shown in the above table. Early color television receivers, such as the RCA CT-100 , were faithful to this specification (which was based on prevailing motion picture standards), having a larger gamut than most of today's monitors. Their low-efficiency phosphors (notably in the Red) were weak and long-persistent, leaving trails after moving objects. Starting in the late 1950s, picture tube phosphors would sacrifice saturation for increased brightness; this deviation from

7280-591: The system off the air until June 1951, and regular broadcasts only lasted a few months before manufacture of all color television sets was banned by the Office of Defense Mobilization in October, ostensibly due to the Korean War . A variant of the CBS system was later used by NASA to broadcast pictures of astronauts from space. CBS rescinded its system in March 1953, and the FCC replaced it on December 17, 1953, with

7371-658: The time the color standard was promulgated, the color subcarrier frequency was constructed as composite frequency assembled from small integers, in this case 5×7×9/(8×11) MHz. The horizontal line rate was reduced to approximately 15,734 lines per second (3.579545×2/455 MHz = 9/572 MHz) from 15,750 lines per second, and the frame rate was reduced to 30/1.001 ≈ 29.970 frames per second (the horizontal line rate divided by 525 lines/frame) from 30 frames per second. These changes amounted to 0.1 percent and were readily tolerated by then-existing television receivers. The first publicly announced network television broadcast of

7462-491: The time; only color sets would recognize the chroma signal, which was essentially ignored by black and white sets. The red, green, and blue primary color signals ( R ′ G ′ B ′ ) {\displaystyle (R^{\prime }G^{\prime }B^{\prime })} are weighted and summed into a single luma signal, designated Y ′ {\displaystyle Y^{\prime }} (Y prime) which takes

7553-597: The true speed of video and audio, and the pitch of voices, sound effects, and musical performances, in television films from those regions. For example, they may wonder whether the Jeremy Brett series of Sherlock Holmes television films, made in the 1980s and early 1990s, was shot at 24 fps and then transmitted at an artificially fast speed in 25-fps regions, or whether it was shot at 25 fps natively and then slowed to 24 fps for NTSC exhibition. These discrepancies exist not only in television broadcasts over

7644-409: The two carriers) is an odd multiple of half the line rate, which is the necessary condition for the dots on successive lines to be opposite in phase, making them least noticeable. The 59.94 rate is derived from the following calculations. Designers chose to make the chrominance subcarrier frequency an n + 0.5 multiple of the line frequency to minimize interference between the luminance signal and

7735-449: The video signal carrier . 3.58 MHz is often stated as an abbreviation instead of 3.579545 MHz. For a color TV to recover hue information from the color subcarrier, it must have a zero-phase reference to replace the previously suppressed carrier. The NTSC signal includes a short sample of this reference signal, known as the colorburst , located on the back porch of each horizontal synchronization pulse. The color burst consists of

7826-466: The video signal, e.g. {2, 4, 6, ..., 524}) are drawn in the first field, and the odd-numbered (every other line that would be odd if counted in the video signal, e.g. {1, 3, 5, ..., 525}) are drawn in the second field, to yield a flicker-free image at the field refresh frequency of 60 ⁄ 1.001  Hz (approximately 59.94 Hz). For comparison, 625 lines (576 visible) systems, usually used with PAL-B/G and SECAM color, and so have

7917-462: Was 3×5×5×7=525 . (For the same reason, 625-line PAL-B/G and SECAM uses 5×5×5×5 , the old British 405-line system used 3×3×3×3×5 , the French 819-line system used 3×3×7×13 etc.) Colorimetry refers to the specific colorimetric characteristics of the system and its components, including the specific primary colors used, the camera,

8008-468: Was assigned the designation System M . It is also known as EIA standard 170. In 1953, a second NTSC standard was adopted, which allowed for color television broadcast compatible with the existing stock of black-and-white receivers. It is one of three major color formats for analog television, the others being PAL and SECAM . NTSC color is usually associated with the System M; this combination

8099-886: Was further recommended that studio monitors incorporate similar color correction circuits so that broadcasters would transmit pictures encoded for the original 1953 colorimetric values, in accordance with FCC standards. In 1987, the Society of Motion Picture and Television Engineers (SMPTE) Committee on Television Technology, Working Group on Studio Monitor Colorimetry, adopted the SMPTE C (Conrac) phosphors for general use in Recommended Practice 145, prompting many manufacturers to modify their camera designs to directly encode for SMPTE C colorimetry without color correction, as approved in SMPTE standard 170M, "Composite Analog Video Signal – NTSC for Studio Applications" (1994). As

8190-717: Was later used by Minolta , Panasonic , and Canon for their still video cameras introduced in the mid-to-late 1980s, such as the Canon Xapshot from 1988 (also known as the Canon Ion in Europe and the Canon Q-PIC in Japan). Besides still video cameras, stand-alone recorders & players were also available for the VF format, that could record from or output a composite video signal, to or from an external source (such as

8281-401: Was then compared with the 60 Hz power-line frequency and any discrepancy corrected by adjusting the frequency of the master oscillator. For interlaced scanning, an odd number of lines per frame was required in order to make the vertical retrace distance identical for the odd and even fields, which meant the master oscillator frequency had to be divided down by an odd number. At the time,

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