title: Potassium dichromate

text: Potassium dichromate is usually prepared by the reaction of potassium chloride on sodium dichromate. Alternatively, it can be also obtained from potassium chromate by roasting chromite ore with potassium hydroxide. It is soluble in water and in the dissolution process it ionizes:


title: Potassium dichromate

text: Potassium dichromate is an oxidising agent in organic chemistry, and is milder than potassium permanganate. It is used to oxidize alcohols. It converts primary alcohols into aldehydes and, under more forcing conditions, into carboxylic acids. In contrast, potassium permanganate tends to give carboxylic acids as the sole products. Secondary alcohols are converted into ketones. For example, menthone may be prepared by oxidation of menthol with acidified dichromate. Tertiary alcohols cannot be oxidized.


title: Potassium dichromate

text: In an aqueous solution the color change exhibited can be used to test for distinguishing aldehydes from ketones. Aldehydes reduce dichromate from the +6 to the +3 oxidation state, changing color from orange to green. This color change arises because the aldehyde can be oxidized to the corresponding carboxylic acid. A ketone will show no such change because it cannot be oxidized further, and so the solution will remain orange.


title: Potassium dichromate

text: When an alkali is added to an orange-red solution containing dichromate ions, a yellow solution is obtained due to the formation of chromate ions (). For example, potassium chromate is produced industrially using potash:


title: Potassium dichromate

text: Potassium dichromate has few major applications, as the sodium salt is dominant industrially. The main use is as a precursor to potassium chrome alum, used in leather tanning.


title: Potassium dichromate

text: Like other chromium(VI) compounds (chromium trioxide, sodium dichromate), potassium dichromate has been used to prepare "chromic acid" for cleaning glassware and etching materials. Because of safety concerns associated with hexavalent chromium, this practice has been largely discontinued.


title: Potassium dichromate

text: It is used as an ingredient in cement in which it retards the setting of the mixture and improves its density and texture. This usage commonly causes contact dermatitis in construction workers.


title: Potassium dichromate

text: In 1839, Mungo Ponton discovered that paper treated with a solution of potassium dichromate was visibly tanned by exposure to sunlight, the discoloration remaining after the potassium dichromate had been rinsed out. In 1852, Henry Fox Talbot discovered that exposure to ultraviolet light in the presence of potassium dichromate hardened organic colloids such as gelatin and gum arabic, making them less soluble.


title: Potassium dichromate

text: These discoveries soon led to the carbon print, gum bichromate, and other photographic printing processes based on differential hardening. Typically, after exposure, the unhardened portion was rinsed away with warm water, leaving a thin relief that either contained a pigment included during manufacture or was subsequently stained with a dye. Some processes depended on the hardening only, in combination with the differential absorption of certain dyes by the hardened or unhardened areas. Because some of these processes allowed the use of highly stable dyes and pigments, such as carbon black, prints with an extremely high degree of archival permanence and resistance to fading from prolonged exposure to light could be produced.


title: Potassium dichromate

text: Dichromated colloids were also used as photoresists in various industrial applications, most widely in the creation of metal printing plates for use in photomechanical printing processes.


title: Potassium dichromate

text: "Chromium intensification" or "Photochromos" uses potassium dichromate together with equal parts of concentrated hydrochloric acid diluted down to approximately 10% v/v to treat weak and thin negatives of black and white photograph roll. This solution reconverts the elemental silver particles in the film to silver chloride. After thorough washing and exposure to actinic light, the film can be redeveloped to its end-point yielding a stronger negative which is able to produce a more satisfactory print.


title: Potassium dichromate

text: A potassium dichromate solution in sulfuric acid can be used to produce a reversal negative (that is, a positive transparency from a negative film). This is effected by developing a black and white film but allowing the development to proceed more or less to the end point. The development is then stopped by copious washing and the film then treated in the acid dichromate solution. This converts the silver metal to silver sulfate, a compound that is insensitive to light. After thorough washing and exposure to actinic light, the film is developed again allowing the previously unexposed silver halide to be reduced to silver metal.


title: Potassium dichromate

text: The results obtained can be unpredictable, but sometimes excellent results are obtained producing images that would otherwise be unobtainable. This process can be coupled with solarisation so that the end product resembles a negative and is suitable for printing in the normal way.


title: Potassium dichromate

text: Cr(VI) compounds have the property of tanning animal proteins when exposed to strong light. This quality is used in photographic screen-printing.


title: Potassium dichromate

text: In screen-printing a fine screen of bolting silk or similar material is stretched taut onto a frame similar to the way canvas is prepared before painting. A colloid sensitized with a dichromate is applied evenly to the taut screen. Once the dichromate mixture is dry, a full-size photographic positive is attached securely onto the surface of the screen, and the whole assembly exposed to strong light – times vary from 3 minutes to a half an hour in bright sunlight – hardening the exposed colloid. When the positive is removed, the unexposed mixture on the screen can be washed off with warm water, leaving the hardened mixture intact, acting as a precise mask of the desired pattern, which can then be printed with the usual screen-printing process.


title: Potassium dichromate

text: Because it is non-hygroscopic, potassium dichromate is a common reagent in classical "wet tests" in analytical chemistry.


title: Potassium dichromate

text: The concentration of ethanol in a sample can be determined by back titration with acidified potassium dichromate. Reacting the sample with an excess of potassium dichromate, all ethanol is oxidized to acetic acid:


title: Potassium dichromate

text: The excess dichromate is determined by titration against sodium thiosulfate. Adding the amount of excess dichromate from the initial amount, gives the amount of ethanol present. Accuracy can be improved by calibrating the dichromate solution against a blank.


title: Potassium dichromate

text: One major application for this reaction is in old police breathalyzer tests. When alcohol vapor makes contact with the orange dichromate-coated crystals, the color changes from Cr(VI) orange to Cr(III) green. The degree of the color change is directly related to the level of alcohol in the suspect's breath.


title: Potassium dichromate

text: When dissolved in an approximately 35% nitric acid solution it is called Schwerter's solution and is used to test for the presence of various metals, notably for determination of silver purity. Pure silver will turn the solution bright red, sterling silver will turn it dark red, low grade coin silver (0.800 fine) will turn brown (largely due to the presence of copper which turns the solution brown) and even green for 0.500 silver.


title: Potassium dichromate

text: Brass turns dark brown, copper turns brown, lead and tin both turn yellow while gold and palladium do not change.


title: Potassium dichromate

text: Potassium dichromate paper can be used to test for sulfur dioxide, as it turns distinctively from orange to green. This is typical of all redox reactions where hexavalent chromium is reduced to trivalent chromium. Therefore, it is not a conclusive test for sulfur dioxide. The final product formed is Cr(SO).


title: Potassium dichromate

text: Potassium dichromate is used to stain certain types of wood by darkening the tannins in the wood. It produces deep, rich browns that cannot be achieved with modern color dyes. It is a particularly effective treatment on mahogany.


title: Potassium dichromate

text: Potassium dichromate occurs naturally as the rare mineral lopezite. It has only been reported as vug fillings in the nitrate deposits of the Atacama desert of Chile and in the Bushveld igneous complex of South Africa.


title: Potassium dichromate

text: Potassium dichromate is one of the most common causes of chromium dermatitis; chromium is highly likely to induce sensitization leading to dermatitis, especially of the hand and fore-arms, which is chronic and difficult to treat. Toxicological studies have further illustrated its highly toxic nature. With rabbits and rodents, concentrations as low as 14 mg/kg have shown a 50% fatality rate amongst test groups. Aquatic organisms are especially vulnerable if exposed, and hence responsible disposal according to the local environmental regulations is advised.


title: Potassium dichromate

text: As with other Cr(VI) compounds, potassium dichromate is carcinogenic. The compound is also corrosive and exposure may produce severe eye damage or blindness. Human exposure further encompasses impaired fertility, heritable


title: Caribou (album)

text: Caribou is the eighth studio album by English musician Elton John, released on 24 June 1974 by MCA Records in the US and on 28 June by DJM Records in the UK. It was his fourth chart-topping album in the United States and his third in the United Kingdom. The album contains the singles "Don't Let the Sun Go Down on Me", which reached number 16 in the UK Singles Chart and number two in the US, and "The Bitch Is Back", which reached number 15 in the UK and number four in the US. Both singles reached number one in Canada on the "RPM 100" national Top Singles Chart, as did the album itself.


title: Caribou (album)

text: The album met with lukewarm reviews on its release and legacy reviews do not consider the record to be among John's best work from his early 1970s peak period. However, the album was a commercial success and has been certified double-platinum in the US as well as receiving a gold certification in the UK. The album was nominated for the Grammy Award for Album of the Year at the 17th Annual Grammy Awards.


title: Caribou (album)

text: In the liner notes to the 1995 CD re-release, John described the album as being quickly recorded in January 1974, with only about nine days to get everything recorded, because he and the band "were under enormous pressure" to finish the album and immediately embark on a Japanese tour. Producer Gus Dudgeon added additional backing vocals, horns and other overdubs after John and the band had finished their work. Dudgeon later called the album "a piece of crap ... the sound is the worst, the songs are nowhere, the sleeve came out wrong, the lyrics weren't that good, the singing wasn't all there, the playing wasn't great and the production is just plain lousy".


title: Caribou (album)

text: The album was named after the Caribou Ranch recording studio in Colorado, where part of the album was recorded.


title: Caribou (album)

text: "Ticking" tells the story of a man suffering from a repressed childhood who kills 14 people in a mass shooting in a bar in New York City. Despite being described by "Rolling Stone" critic Tom Nolan as "the centrepiece fiasco" of the album in his 1974 review of "Caribou", in 2015 "Rolling Stone" readers voted the song their second-favourite "deep cut" of lesser-known Elton John songs.


title: Caribou (album)

text: In addition to the singles, John has over the years played several other songs from this album in concert, including "Grimsby", "You're So Static", "Ticking" and "Dixie Lily". The 1995 CD reissue contains four songs from the general period in and around the release of "Caribou", though only two of them, the B-sides "Sick City" and "Cold Highway", were recorded during the album sessions. "Step into Christmas" was recorded during a previous one-off single session, and "Pinball Wizard" was recorded at the Who's Ramport Studios in England, during the sessions for the movie score and soundtrack album of "Tommy".


title: Caribou (album)

text: Tom Nolan of "Rolling Stone" described the album as "dispiriting" and said, "Nearly every song on "Caribou" suffers from a blithe lack of focus, an almost arrogant disregard of the need to establish context or purpose ... Shifting from sentimental to heavy to mocking, [John and Taupin] not only fail to touch all bases but undercut what credence they might possibly have achieved." Criticising the album's production and the superficiality of the songs, he concluded that "Caribou" is "a startlingly empty experience".


title: Caribou (album)

text: Stephen Thomas Erlewine's retrospective review for AllMusic called "Caribou" "a disappointment" and that aside from the two singles, "the album tracks tend to be ridiculous filler on the order of 'Solar Prestige a Gammon' or competent genre exercises like 'You're So Static'".


title: Analog television

text: Analog television is the original television technology that uses analog signals to transmit video and audio. In an analog television broadcast, the brightness, colors and sound are represented by amplitude, phase and frequency of an analog signal.


title: Analog television

text: Analog signals vary over a continuous range of possible values which means that electronic noise and interference may be introduced. Thus with analog, a moderately weak signal becomes snowy and subject to interference. In contrast, picture quality from a digital television (DTV) signal remains good until the signal level drops below a threshold where reception is no longer possible or becomes intermittent.


title: Analog television

text: Analog television may be wireless (terrestrial television and satellite television) or can be distributed over a cable network as cable television.


title: Analog television

text: All broadcast television systems used analog signals before the arrival of DTV. Motivated by the lower bandwidth requirements of compressed digital signals, beginning in the 2000s, a digital television transition is proceeding in most countries of the world, with different deadlines for the cessation of analog broadcasts.


title: Analog television

text: The earliest systems of analog television were mechanical television systems that used spinning disks with patterns of holes punched into the disc to scan an image. A similar disk reconstructed the image at the receiver. Synchronization of the receiver disc rotation was handled through sync pulses broadcast with the image information. Camera systems used similar spinning discs and required intensely bright illumination of the subject for the light detector to work. The reproduced images from these mechanical systems were dim, very low resolution and flickered severely.


title: Analog television

text: Analog television did not really begin as an industry until the development of the cathode-ray tube (CRT), which uses a focused electron beam to trace lines across a phosphor coated surface. The electron beam could be swept across the screen much faster than any mechanical disc system, allowing for more closely spaced scan lines and much higher image resolution. Also, far less maintenance was required of an all-electronic system compared to a mechanical spinning disc system. All-electronic systems became popular with households after World War II.


title: Analog television

text: Broadcasters of analog television encode their signal using different systems. The official systems of transmission were defined by the ITU in 1961 as: A, B, C, D, E, F, G, H, I, K, K1, L, M and N. These systems determine the number of scan lines, frame rate, channel width, video bandwidth, video-audio separation, and so on. A color encoding scheme (NTSC, PAL, or SECAM) could be added to the base monochrome signal. Using RF modulation the signal is then modulated onto a very high frequency (VHF) or ultra high frequency (UHF) carrier wave. Each frame of a television image is composed of scan lines drawn on the screen. The lines are of varying brightness; the whole set of lines is drawn quickly enough that the human eye perceives it as one image. The process repeats and next sequential frame is displayed, allowing the depiction of motion. The analog television signal contains timing and synchronization information so that the receiver can reconstruct a two-dimensional moving image from a one-dimensional time-varying signal.


title: Analog television

text: The first commercial television systems were black-and-white; the beginning of color television was in the 1950s.


title: Analog television

text: A practical television system needs to take luminance, chrominance (in a color system), synchronization (horizontal and vertical), and audio signals, and broadcast them over a radio transmission. The transmission system must include a means of television channel selection.


title: Analog television

text: Analog broadcast television systems come in a variety of frame rates and resolutions. Further differences exist in the frequency and modulation of the audio carrier. The monochrome combinations still existing in the 1950s were standardized by the International Telecommunication Union (ITU) as capital letters A through N. When color television was introduced, the chrominance information was added to the monochrome signals in a way that black and white televisions ignore. In this way backward compatibility was achieved.


title: Analog television

text: There are three standards for the way the additional color information can be encoded and transmitted. The first was the American NTSC system. The European and Australian PAL and the French and former Soviet Union SECAM standards were developed later and attempt to cure certain defects of the NTSC system. PAL's color encoding is similar to the NTSC systems. SECAM, though, uses a different modulation approach than PAL or NTSC. PAL had a late evolution called PALplus, allowing widescreen broadcasts while remaining fully compatible with existing PAL equipment.


title: Analog television

text: In principle, all three color encoding systems can be used with any scan line/frame rate combination. Therefore, in order to describe a given signal completely, it's necessary to quote the color system and the broadcast standard as a capital letter. For example, the United States, Canada, Mexico and South Korea use NTSC-M, Japan uses NTSC-J, the UK uses PAL-I, France uses SECAM-L, much of Western Europe and Australia use PAL-B/G, most of Eastern Europe uses SECAM-D/K or PAL-D/K and so on.


title: Analog television

text: However, not all of these possible combinations actually exist. NTSC is currently only used with system M, even though there were experiments with NTSC-A (405 line) in the UK and NTSC-N (625 line) in part of South America. PAL is used with a variety of 625-line standards (B, G, D, K, I, N) but also with the North American 525-line standard, accordingly named PAL-M. Likewise, SECAM is used with a variety of 625-line standards.


title: Analog television

text: For this reason, many people refer to any 625/25 type signal as "PAL" and to any 525/30 signal as "NTSC", even when referring to digital signals; for example, on DVD-Video, which does not contain any analog color encoding, and thus no PAL or NTSC signals at all.


title: Analog television

text: Although a number of different broadcast television systems were in use worldwide, the same principles of operation apply.


title: Analog television

text: A cathode-ray tube (CRT) television displays an image by scanning a beam of electrons across the screen in a pattern of horizontal lines known as a raster. At the end of each line, the beam returns to the start of the next line; at the end of the last line, the beam returns to the beginning of the first line at the top of the screen. As it passes each point, the intensity of the beam is varied, varying the luminance of that point. A color television system is similar except there are three beams that scan together and an additional signal known as chrominance controls the color of the spot.


title: Analog television

text: When analog television was developed, no affordable technology for storing video signals existed; the luminance signal had to be generated and transmitted at the same time at which it is displayed on the CRT. It was therefore essential to keep the raster scanning in the camera (or other device for producing the signal) in exact synchronization with the scanning in the television.


title: Analog television

text: The physics of the CRT require that a finite time interval be allowed for the spot to move back to the start of the next line ("horizontal retrace") or the start of the screen ("vertical retrace"). The timing of the luminance signal must allow for this.


title: Analog television

text: The human eye has a characteristic called phi phenomenon. Quickly displaying successive scan images creates the illusion of smooth motion. Flickering of the image can be partially solved using a long persistence phosphor coating on the CRT so that successive images fade slowly. However, slow phosphor has the negative side-effect of causing image smearing and blurring when there is rapid on-screen motion occurring.


title: Analog television

text: The maximum frame rate depends on the bandwidth of the electronics and the transmission system, and the number of horizontal scan lines in the image. A frame rate of 25 or 30 hertz is a satisfactory compromise, while the process of interlacing two video fields of the picture per frame is used to build the image. This process doubles the apparent number of video frames per second and further reduces flicker and other defects in transmission.


title: Analog television

text: The television system for each country will specify a number of television channels within the UHF or VHF frequency ranges. A channel actually consists of two signals: the picture information is transmitted using amplitude modulation on one carrier frequency, and the sound is transmitted with frequency modulation at a frequency at a fixed offset (typically 4.5 to 6 MHz) from the picture signal.


title: Analog television

text: The channel frequencies chosen represent a compromise between allowing enough bandwidth for video (and hence satisfactory picture resolution), and allowing enough channels to be packed into the available frequency band. In practice a technique called vestigial sideband is used to reduce the channel spacing, which would be nearly twice the video bandwidth if pure AM was used.


title: Analog television

text: Signal reception is invariably done via a superheterodyne receiver: the first stage is a "tuner" which selects a television channel and frequency-shifts it to a fixed intermediate frequency (IF). The signal amplifier performs amplification to the IF stages from the microvolt range to fractions of a volt.


title: Analog television

text: At this point the IF signal consists of a video carrier signal at one frequency and the sound carrier at a fixed offset in frequency. A demodulator recovers the video signal. Also at the output of the same demodulator is a new frequency modulated sound carrier at the offset frequency. In some sets made before 1948, this was filtered out, and the sound IF of about 22 MHz was sent to an FM demodulator to recover the basic sound signal. In newer sets, this new carrier at the offset frequency was allowed to remain as "intercarrier sound", and it was sent to an FM demodulator to recover the basic sound signal. One particular advantage of intercarrier sound is that when the front panel fine tuning knob is adjusted, the sound carrier frequency does not change with the tuning, but stays at the above-mentioned offset frequency. Consequently, it is easier to tune the picture without losing the sound.


title: Analog television

text: So the FM sound carrier is then demodulated, amplified, and used to drive a loudspeaker. Until the advent of the NICAM and MTS systems, television sound transmissions were monophonic.


title: Analog television

text: The video carrier is demodulated to give a composite video signal containing luminance, chrominance and synchronization signals. The result is identical to the composite video format used by analog video devices such as VCRs or CCTV cameras. To ensure good linearity and thus fidelity, consistent with affordable manufacturing costs of transmitters and receivers, the video carrier is never modulated to the extent that it is shut off altogether. When intercarrier sound was introduced later in 1948, not completely shutting off the carrier had the side effect of allowing intercarrier sound to be economically implemented.


title: Analog television

text: Each line of the displayed image is transmitted using a signal as shown above. The same basic format (with minor differences mainly related to timing and the encoding of color) is used for PAL, NTSC, and SECAM television systems. A monochrome signal is identical to a color one, with the exception that the elements shown in color in the diagram (the colorburst, and the chrominance signal) are not present.


title: Analog television

text: The "front porch" is a brief (about 1.5 microsecond) period inserted between the end of each transmitted line of picture and the leading edge of the next line's sync pulse. Its purpose was to allow voltage levels to stabilise in older televisions, preventing interference between picture lines. The "front porch" is the first component of the horizontal blanking interval which also contains the horizontal sync pulse and the "back porch".


title: Analog television

text: The "back porch" is the portion of each scan line between the end (rising edge) of the horizontal sync pulse and the start of active video. It is used to restore the black level (300 mV) reference in analog video. In signal processing terms, it compensates for the fall time and settling time following the sync pulse.


title: Analog television

text: In color television systems such as PAL and NTSC, this period also includes the colorburst signal. In the SECAM system, it contains the reference subcarrier for each consecutive color difference signal in order to set the zero-color reference.


title: Analog television

text: In some professional systems, particularly satellite links between locations, the digital audio is embedded within the line sync pulses of the video signal, to save the cost of renting a second channel. The name for this proprietary system is Sound-in-Syncs.


title: Analog television

text: The luminance component of a composite video signal varies between 0 V and approximately 0.7 V above the "black" level. In the NTSC system, there is a "blanking" signal level used during the front porch and back porch, and a "black" signal level 75 mV above it; in PAL and SECAM these are identical.


title: Analog television

text: In a monochrome receiver, the luminance signal is amplified to drive the control grid in the electron gun of the CRT. This changes the intensity of the electron beam and therefore the brightness of the spot being scanned. Brightness and contrast controls determine the DC shift and amplification, respectively.


title: Analog television

text: A color signal conveys picture information for each of the red, green, and blue components of an image. However, these are not simply transmitted as three separate signals, because: such a signal would not be compatible with monochrome receivers, an important consideration when color broadcasting was first introduced. It would also occupy three times the bandwidth of existing television, requiring a decrease in the number of television channels available.


title: Analog television

text: Instead, the RGB signals are converted into YUV form, where the Y signal represents the luminance of the colors in the image. Because the rendering of colors in this way is the goal of both monochrome film and television systems, the Y signal is ideal for transmission as the luminance signal. This ensures a monochrome receiver will display a correct picture in black and white, where a given color is reproduced by a shade of gray that correctly reflects how light or dark the original color is.


title: Analog television

text: The U and V signals are "color difference" signals. The U signal is the difference between the B signal and the Y signal, also known as B minus Y (B-Y), and the V signal is the difference between the R signal and the Y signal, also known as R minus Y (R-Y). The U signal then represents how purplish-blue or its complementary color, yellowish-green, the color is, and the V signal how purplish-red or it's complementary, greenish-cyan, it is. The advantage of this scheme is that the U and V signals are zero when the picture has no color content. Since the human eye is more sensitive to detail in luminance than in color, the U and V signals can be transmitted with reduced bandwidth with acceptable results.


title: Analog television

text: In the receiver, a single demodulator can extract an additive combination of U plus V. An example is the X demodulator used in the X/Z demodulation system. In that same system, a second demodulator, the Z demodulator, also extracts an additive combination of U plus V, but in a different ratio. The X and Z color difference signals are further matrixed into three color difference signals, (R-Y), (B-Y), and (G-Y). The combinations of usually two, but sometimes three demodulators were:


title: Analog television

text: In the end, further matrixing of the above color-difference signals c through f yielded the three color-difference signals, (R-Y), (B-Y), and (G-Y).


title: Analog television

text: The R, G, and B signals in the receiver needed for the display device (CRT, Plasma display, or LCD display) are electronically derived by matrixing as follows: R is the additive combination of (R-Y) with Y, G is the additive combination of (G-Y) with Y, and B is the additive combination of (B-Y) with Y. All of this is accomplished electronically. It can be seen that in the combining process, the low-resolution portion of the Y signals cancel out, leaving R, G, and B signals able to render a low-resolution image in full color. However, the higher resolution portions of the Y signals do not cancel out, and so are equally present in R, G, and B, producing the higher-resolution image detail in monochrome, although it appears to the human eye as a full-color and full-resolution picture.


title: Analog television

text: In the NTSC and PAL color systems, U and V are transmitted by using quadrature amplitude modulation of a subcarrier. This kind of modulation applies two independent signals to one subcarrier, with the idea that both signals will be recovered independently at the receiving end. For NTSC, the subcarrier is at 3.58 MHz. For the PAL system it is at 4.43 MHz. The subcarrier itself is not included in the modulated signal (suppressed carrier), it is the subcarrier sidebands that carry the U and V information. The usual reason for using suppressed carrier is that it saves on transmitter power. In this application a more important advantage is that the color signal disappears entirely in black and white scenes. The subcarrier is within the bandwidth of the main luminance signal and consequently can cause undesirable artifacts on the picture, all the more noticeable in black and white receivers.


title: Analog television

text: A small sample of the subcarrier, the colorburst, is included in the horizontal blanking portion, which is not visible on the screen. This is necessary to give the receiver a phase reference for the modulated signal. Under quadrature amplitude modulation the modulated chrominance signal changes phase as compared to its subcarrier and also changes amplitude. The chrominance amplitude (when considered together with the Y signal) represents the approximate saturation of a color, and the chrominance phase against the subcarrier reference approximately represents the hue of the color. For particular test colors found in the test color bar pattern, exact amplitudes and phases are sometimes defined for test and troubleshooting purposes only.


title: Analog television

text: Due to the nature of the quadrature amplitude modulation process that created the chrominance signal, at certain times, the signal represents only the U signal, and 70 nanoseconds (NTSC) later, it represents only the V signal. About 70 nanoseconds later still, -U, and another 70 nanoseconds, -V. So to extract U, a synchronous demodulator is utilized, which uses the subcarrier to briefly gate the chroma every 280 nanoseconds, so that the output is only a train of discrete pulses, each having an amplitude that is the same as the original U signal at the corresponding time. In effect, these pulses are discrete-time analog samples of the U signal. The pulses are then low-pass filtered so that the original analog continuous-time U signal is recovered. For V, a 90-degree shifted subcarrier briefly gates the chroma signal every 280 nanoseconds, and the rest of the process is identical to that used for the U signal.


title: Analog television

text: Gating at any other time than those times mentioned above will yield an additive mixture of any two of U, V, -U, or -V. One of these "off-axis" (that is, of the U and V axis) gating methods is called I/Q demodulation. Another much more popular off-axis scheme was the X/Z demodulation system. Further matrixing recovered the original U and V signals. This scheme was actually the most popular demodulator scheme throughout the 60s.


title: Analog television

text: The above process uses the subcarrier. But as previously mentioned, it was deleted before transmission, and only the chroma is transmitted. Therefore, the receiver must reconstitute the subcarrier. For this purpose, a short burst of the subcarrier, known as the colorburst, is transmitted during the back porch (re-trace blanking period) of each scan line. A subcarrier oscillator in the receiver locks onto this signal (see phase-locked loop) to achieve a phase reference, resulting in the oscillator producing the reconstituted subcarrier.


title: Analog television

text: NTSC uses this process unmodified. Unfortunately, this often results in poor color reproduction due to phase errors in the received signal, caused sometimes by multipath, but mostly by poor implementation at the studio end. With the advent of solid-state receivers, cable TV, and digital studio equipment for conversion to an over-the-air analog signal, these NTSC problems have been largely fixed, leaving operator error at the studio end as the sole color rendition weakness of the NTSC system. In any case, the PAL D (delay) system mostly corrects these kinds of errors by reversing the phase of the signal on each successive line, and averaging the results over pairs of lines. This process is achieved by the use of a 1H (where H = horizontal scan frequency) duration delay line. Phase shift errors between successive lines are therefore canceled out and the wanted signal amplitude is increased when the two in-phase (coincident) signals are re-combined.


title: Analog television

text: NTSC is more spectrum efficient than PAL, giving more picture detail for a given bandwidth. This is because sophisticated comb filters in receivers are more effective with NTSC's 4 field color phase cadence compared to PAL's 8 field cadence. However, in the end, the larger channel width of most PAL systems in Europe still give their PAL systems the edge in transmitting more picture detail.


title: Analog television

text: In the SECAM television system, U and V are transmitted on "alternate" lines, using simple frequency modulation of two different color subcarriers.


title: Analog television

text: In some analog color CRT displays, starting in 1956, the brightness control signal (luminance) is fed to the cathode connections of the electron guns, and the color difference signals (chrominance signals) are fed to the control grids connections. This simple CRT matrix mixing technique was replaced in later solid state designs of signal processing with the original matrixing method used in the 1954 and 1955 color TV receivers.


title: Analog television

text: Synchronizing pulses added to the video signal at the end of every scan line and video frame ensure that the sweep oscillators in the receiver remain locked in step with the transmitted signal so that the image can be reconstructed on the receiver screen.


title: Analog television

text: A "sync separator" circuit detects the sync voltage levels and sorts the pulses into horizontal and vertical sync.


title: Analog television

text: The horizontal synchronization pulse ("horizontal sync", or "HSync"), separates the scan lines. The horizontal sync signal is a single short pulse which indicates the start of every line. The rest of the scan line follows, with the signal ranging from 0.3 V (black) to 1 V (white), until the next horizontal or vertical synchronization pulse.


title: Analog television

text: The format of the horizontal sync pulse varies. In the 525-line NTSC system it is a 4.85 μs-long pulse at 0 V. In the 625-line PAL system the pulse is 4.7 μs synchronization pulse at 0 V . This is lower than the amplitude of any video signal ("blacker than black") so it can be detected by the level-sensitive "sync stripper" circuit of the receiver.


title: Analog television

text: Vertical synchronization (also called vertical sync or VSync) separates the video fields. In PAL and NTSC, the vertical sync pulse occurs within the vertical blanking interval. The vertical sync pulses are made by prolonging the length of HSYNC pulses through almost the entire length of the scan line.


title: Analog television

text: The "vertical sync" signal is a series of much longer pulses, indicating the start of a new field. The sync pulses occupy the whole line interval of a number of lines at the beginning and end of a scan; no picture information is transmitted during vertical retrace. The pulse sequence is designed to allow horizontal sync to continue during vertical retrace; it also indicates whether each field represents even or odd lines in interlaced systems (depending on whether it begins at the start of a horizontal line, or midway through).


title: Analog television

text: Each pre- or post- equalizing pulse consists in half a scan line of black signal: 2 μs at 0 V, followed by 30 μs at 0.3 V.


title: Analog television

text: Each long sync pulse consists of an equalizing pulse with timings inverted: 30 μs at 0  V, followed by 2 μs at 0.3  V.


title: Analog television

text: In video production and computer graphics, changes to the image are often kept in step with the vertical synchronization pulse to avoid visible discontinuity of the image. Since the frame buffer of a computer graphics display imitates the dynamics of a cathode-ray display, if it is updated with a new image while the image is being transmitted to the display, the display shows a mishmash of both frames, producing a page tearing artifact partway down the image.


title: Analog television

text: Vertical synchronization eliminates this by timing frame buffer fills to coincide with the vertical blanking interval, thus ensuring that only whole frames are seen on-screen. Software such as video games and computer-aided design (CAD) packages often allow vertical synchronization as an option, because it delays the image update until the vertical blanking interval. This produces a small penalty in latency because the program has to wait until the video controller has finished transmitting the image to the display before continuing. Triple buffering reduces this latency significantly.


title: Analog television

text: Two-timing intervals are defined – the "front porch" between the end of the displayed video and the start of the sync pulse, and the "back porch" after the sync pulse and before the displayed video. These and the sync pulse itself are called the "horizontal blanking" (or "retrace") "interval" and represent the time that the electron beam in the CRT is returning to the start of the next display line.


title: Analog television

text: Analog television receivers and composite monitors often provide manual controls to adjust horizontal and vertical timing.


title: Analog television

text: The sweep (or deflection) oscillators were designed to run without a signal from the television station (or VCR, computer, or other composite video source). This provides a blank canvas, similar to today's "CHECK SIGNAL CABLE" messages on monitors: it allows the television receiver to display a raster to confirm the basic operation of the set's most fundamental circuits, and to allow an image to be presented during antenna placement. With sufficient signal strength, the receiver's sync separator circuit would split timebase pulses from the incoming video and use them to reset the horizontal and vertical oscillators at the appropriate time to synchronize with the signal from the station.


title: Analog television

text: The free-running oscillation of the horizontal circuit is especially critical, as the horizontal deflection circuits typically power the flyback transformer (which provides acceleration potential for the CRT) as well as the filaments for the high voltage rectifier tube and sometimes the filament(s) of the CRT itself. Without the operation of the horizontal oscillator and output stages, for virtually every analog television receiver since the 1940s, there will be absolutely no illumination of the CRT's face.


title: Analog television

text: The lack of precision timing components in early television receivers meant that the timebase circuits occasionally needed manual adjustment.


title: Analog television

text: If their free-run frequencies were too far from the actual line and field rates, the circuits would not be able to follow the incoming sync signals.


title: Analog television

text: Loss of horizontal synchronization usually resulted in an unwatchable picture; loss of vertical synchronization would produce an image rolling up or down the screen.


title: Analog television

text: The adjustment took the form of "horizontal hold" and "vertical hold" controls, usually on the front panel along with other common controls. These adjusted the free-run frequencies of the corresponding timebase oscillators.


title: Analog television

text: Properly working, adjusting a horizontal or vertical hold should cause the picture to almost "snap" into place on the screen; this is called "sync lock". A slowly rolling vertical picture demonstrates that the vertical oscillator is nearly synchronized with the television station but is not locking to it, often due to a weak signal or a failure in the sync separator stage not resetting the oscillator. Sometimes, the black interval bar will almost stop at the right place, again indicating a fault in sync separation is not properly resetting the vertical oscillator.


title: Analog television

text: Horizontal sync errors cause the image to be torn diagonally and repeated across the screen as if it were wrapped around a screw or a barber's pole; the greater the error, the more "copies" of the image will be seen at once wrapped around the barber pole. Given the importance of the horizontal sync circuit as a power supply to many subcircuits in the receiver, they may begin to malfunction as well; and horizontal output components that were designed to work together in a resonant circuit may become damaged.


title: Analog television

text: In the earliest electronic television receivers (1930s-1950s), the time base for the sweep oscillators was generally derived from RC circuits based on carbon resistors and paper capacitors. After turning on the receiver, the vacuum tubes in the set would warm up and the oscillators would begin to run, allowing a watchable picture. Resistors were generally simple pieces of carbon inside a Bakelite enclosure, and the capacitors were usually alternating layers of paper and aluminum foil inside cardboard tubes sealed with bee's wax. Moisture ingress (from ambient air humidity) as well as thermal instability of these components affected their electrical values. As the heat from the tubes and the electrical currents passing through the RC circuits warmed them up, the electrical properties of the RC timebase would shift, causing the oscillators to drift in frequency to a point that they could no longer be synchronized with the received pulses coming from the TV station via the sync separator circuit, causing tearing (horizontal) or rolling (vertical).


title: Analog television

text: Hermetically-sealed passive components and cooler-running semiconductors as active components gradually improved reliability to the point where the horizontal hold was moved to the rear of the set first, and the vertical hold control (due to the longer period in the RC constant) persisted as a front panel control well into the 1970s as the consistency of larger-value capacitors increased.


title: Analog television

text: By the early 1980s the efficacy of the synchronization circuits, plus the inherent stability of the sets' oscillators, had been improved to the point where these controls were no longer necessary. Integrated Circuits which eliminated the horizontal hold control were starting to appear as early as 1969.


title: Analog television

text: The final generations of analog television receivers (most TV sets with internal on-screen displays to adjust brightness, color, tint, contrast) used "TV-set-on-a-chip" designs where the receiver's timebases were divided down from crystal oscillators, usually based on the 3.58  MHz NTSC colorburst reference. PAL and SECAM receivers were similar though operating at different frequencies. With these sets, adjustment of the free-running frequency of either sweep oscillator was either physically impossible (being derived inside the integrated circuit) or possibly through a hidden service mode typically offering only NTSC/PAL frequency switching, accessible through the On-Screen Display's menu system.


title: Analog television

text: Horizontal and Vertical Hold controls were rarely used in CRT-based computer monitors, as the quality and consistency of components were quite high by the advent of the computer age, but might be found on some composite monitors used with the 1970s-1980s home or personal computers.


title: Analog television

text: The tuner is the object which "plucks" the television signals out of the air, with the aid of an antenna. There are two types of tuners in analog television, VHF and UHF tuners. The VHF tuner selects the VHF television frequency. This consists of a 4 MHz video bandwidth and a 2  MHz audio bandwidth. It then amplifies the signal and converts it to a 45.75 MHz Intermediate Frequency (IF) amplitude-modulated picture and a 41.25 MHz IF frequency-modulated audio carrier.


title: Analog television

text: The IF amplifiers are centered at 44 MHz for optimal frequency transference of the audio and frequency carriers. What centers this frequency is the IF transformer. They are designed for a certain amount of bandwidth to encompass the audio and video. It depends on the number of stages (the amplifier between the transformers). Most of the early television sets (1939–45) used 4 stages with specially designed video amplifier tubes (the type 1852/6AC7). In 1946 the RCA presented a new innovation in television; the RCA 630TS. Instead of using the 1852 octal tube, it uses the 6AG5 7-pin miniature tube. It still had 4 stages, but it was 1/2 the size. Soon all of the manufactures followed RCA and designed better IF stages. They developed higher amplification tubes, and lower stage counts with more amplification. When the tube era came to an end in the mid-70s, they had shrunk the IF stages down to 1-2 (depending on the set) and with the same amplification as the 4 stage, 1852 tube sets. Like radio, television has Automatic Gain Control (AGC). This controls the gain of the IF amplifier stages and the tuner. More of this will be discussed below.


title: Analog television

text: The video amp and output amplifier consist of a low linear pentode or a high powered transistor. The video amp and output stage separate the 45.75 MHz from the 41.25 MHz. It simply uses a diode to detect the video signal. But the frequency-modulated audio is still in the video. Since the diode only detects AM signals, the FM audio signal is still in the video in the form of a 4.5 MHz signal. There are two ways to attach this problem, and both of them work. We can detect the signal before it enters into the video amplifier, or do it after the audio amplifier. Many television sets (1946 to late 1960s) used the after video amplification method, but of course, there is the occasional exception. Many of the later set late (1960s-now) use the before-the-video amplifier way. In some of the early television sets (1939–45) used its own separate tuner, so there was no need for a detection stage next to the amplifier. After the video detector, the video is amplified and sent to the sync separator and then to the picture tube.


title: Analog television

text: At this point, we will now look at the audio section. The means of detection of the audio signal is by a 4.5 MHz traps coil/transformer. After that, it then goes to a 4.5 MHz amplifier. This amplifier prepares the signal for the 4.5Mhz detector. It then goes through a 4.5 MHz IF transformer to the detector. In television, there are 2 ways of detecting FM signals. One way is by the ratio detector. This is simple but very hard to align. The next is a relatively simple detector. This is the quadrature detector. It was invented in 1954. The first tube designed for this purpose was the 6BN6 type. It is easy to align and simple in circuitry. It was such a good design that it is still being used today in the Integrated circuit form. After the detector, it goes to the audio amplifier.


title: Analog television

text: The next part is the sync separator/clipper. This also does more than what is in its name. It also forms the AGC voltage, as previously stated. This sync separator turns the video into a signal that the horizontal and vertical oscillators can use to keep in sync with the video.


title: Analog television

text: The horizontal and vertical oscillators form the raster on the CRT. They are kept in sync by the sync separator. There are many ways to create these oscillators. The first one is the earliest of its kind is the thyratron oscillator. Although it is known to drift, it makes a perfect sawtooth wave. This sawtooth wave is so good that no linearity control is needed. This oscillator was for the electrostatic deflection CRTs. It found some purpose for the electromagnetically deflected CRTs. The next oscillator is the blocking oscillator. It uses a transformer to create a sawtooth wave. This was only used for a brief time period and never was very popular after the beginning. The next oscillator is the multivibrator. This oscillator was probably the most successful. It needed more adjustment than the other oscillators, but it is very simple and effective. This oscillator was so popular that it was used from the early 1950s until today.


title: Analog television

text: The oscillator amplifier is sorted into two categories. The vertical amplifier directly drives the yoke. There is not much to this. It is similar to an audio amplifier. The horizontal oscillator is a different situation. The oscillator must supply the high voltage and the yoke power. This requires a high power flyback transformer, and a high powered tube or transistor. This is a problematic section for CRT televisions because it has to handle high power.


title: Analog television

text: Image synchronization is achieved by transmitting negative-going pulses; in a composite video signal of 1-volt amplitude, these are approximately 0.3  V below the "black level". The "horizontal sync" signal is a single short pulse which indicates the start of every line. Two-timing intervals are defined – the "front porch" between the end of the displayed video and the start of the sync pulse, and the "back porch" after the sync pulse and before the displayed video. These and the sync pulse itself are called the "horizontal blanking" (or "retrace") "interval" and represent the time that the electron beam in the CRT is returning to the start of the next display line.


title: Analog television

text: The "vertical sync" signal is a series of much longer pulses, indicating the start of a new field. The sync pulses occupy the whole of line interval of a number of lines at the beginning and end of a scan; no picture information is transmitted during vertical retrace. The pulse sequence is designed to allow horizontal sync to continue during vertical retrace; it also indicates whether each field represents even or odd lines in interlaced systems (depending on whether it begins at the start of a horizontal line, or midway through).


title: Analog television

text: In the television receiver, a "sync separator" circuit detects the sync voltage levels and sorts the pulses into horizontal and vertical sync.


title: Analog television

text: Loss of horizontal synchronization usually resulted in an unwatchable picture; loss of vertical synchronization would produce an image rolling up or down the screen.


title: Analog television

text: Counting sync pulses, a video line selector picks a selected line from a TV signal, used for teletext, on-screen displays, station identification logos as well as in the industry when cameras were used as a sensor.


title: Analog television

text: In an analog receiver with a CRT display sync pulses are fed to horizontal and vertical "timebase" circuits (commonly called "sweep circuits" in the United States), each consisting of an oscillator and an amplifier. These generate modified sawtooth and parabola current waveforms to scan the electron beam in a linear way. The waveform shapes are necessary to make up for the distance variations from the electron beam source and the screen surface. The oscillators are designed to free-run at frequencies very close to the field and line rates, but the sync pulses cause them to reset at the beginning of each scan line or field, resulting in the necessary synchronization of the beam sweep with the originating signal. The output waveforms from the timebase amplifiers are fed to the horizontal and vertical "deflection coils" wrapped around the CRT tube. These coils produce magnetic fields proportional to the changing current, and these deflect the electron beam across the screen.


title: Analog television

text: In the 1950s, the power for these circuits was derived directly from the mains supply. A simple circuit consisted of a series voltage dropper resistance and a rectifier valve (tube) or semiconductor diode. This avoided the cost of a large high voltage mains supply (50 or 60 Hz) transformer. This type of circuit was used for the thermionic valve (vacuum tube) technology. It was inefficient and produced a lot of heat which led to premature failures in the circuitry. Although failure was common, it was easily repairable.


title: Analog television

text: In the 1960s, semiconductor technology was introduced into timebase circuits. During the late 1960s in the UK, synchronous (with the scan line rate) power generation was introduced into solid state receiver designs. These had very complex circuits in which faults were difficult to trace, but had very efficient use of power.


title: Analog television

text: In the early 1970s AC mains (50 or 60 Hz), and line timebase (15,625 Hz), thyristor based switching circuits were introduced. In the UK use of the simple (50  Hz) types of power, circuits were discontinued. The reason for design changes arose from the electricity supply contamination problems arising from EMI, and supply loading issues due to energy being taken from only the positive half cycle of the mains supply waveform.


title: Analog television

text: Most of the receiver's circuitry (at least in transistor- or IC-based designs) operates from a comparatively low-voltage DC power supply. However, the anode connection for a cathode-ray tube requires a very high voltage (typically 10–30 kV) for correct operation.


title: Analog television

text: This voltage is not directly produced by the main power supply circuitry; instead, the receiver makes use of the circuitry used for horizontal scanning. Direct current (DC), is switched through the line output transformer, and alternating current (AC) is induced into the scan coils. At the end of each horizontal scan line the magnetic field, which has built up in both transformer and scan coils by the current, is a source of latent electromagnetic energy. This stored collapsing magnetic field energy can be captured. The reverse flow, short duration, (about 10% of the line scan time) current from both the line output transformer and the horizontal scan coil is discharged again into the primary winding of the flyback transformer by the use of a rectifier which blocks this negative reverse emf. A small value capacitor is connected across the scan switching device. This tunes the circuit inductances to resonate at a much higher frequency. This slows down (lengthens) the flyback time from the extremely rapid decay rate that would result if they were electrically isolated during this short period. One of the secondary windings on the flyback transformer then feeds this brief high voltage pulse to a Cockcroft–Walton generator design voltage multiplier. This produces the required EHT supply. A flyback converter is a power supply circuit operating on similar principles.


title: Analog television

text: A typical modern design incorporates the flyback transformer and rectifier circuitry into a single unit with a captive output lead, (known as a diode split line output transformer or an Integrated High Voltage Transformer (IHVT)), so that all high-voltage parts are enclosed. Earlier designs used a separate line output transformer and a well-insulated high voltage multiplier unit. The high frequency (15 kHz or so) of the horizontal scanning allows reasonably small components to be used.


title: Analog television

text: In many countries, over-the-air broadcast television of analog audio and analog video signals has been discontinued, to allow the re-use of the television broadcast radio spectrum for other services such as datacasting and subchannels.


title: Analog television

text: The first country to make a wholesale switch to digital over-the-air (terrestrial television) broadcasting was Luxembourg in 2006, followed later in 2006 by the Netherlands; in 2007 by Finland, Andorra, Sweden and Switzerland; in 2008 by Belgium (Flanders) and Germany; in 2009 by the United States (high power stations), southern Canada, the Isle of Man, Norway, and Denmark. In 2010, Belgium (Wallonia), Spain, Wales, Latvia, Estonia, the Channel Islands, San Marino, Croatia, and Slovenia; in 2011 Israel, Austria, Monaco, Cyprus, Japan (excluding Miyagi, Iwate, and Fukushima prefectures), Malta and France; in 2012 the Czech Republic, Arab World, Taiwan, Portugal, Japan (including Miyagi, Iwate, and Fukushima prefectures), Serbia, Italy, Canada, Mauritius, the United Kingdom, the Republic of Ireland, Lithuania, Slovakia, Gibraltar, and South Korea; in 2013, the Republic of Macedonia, Poland, Bulgaria, Hungary, Australia, and New Zealand, completed the transition. The United Kingdom made the transition to digital television between 2008 and 2012, with the exception of Whitehaven, which made the switch over in 2007. The first digital TV-only area in the United Kingdom was Ferryside in Carmarthenshire.


title: Analog television

text: The Digital television transition in the United States for high-powered transmission was completed on 12 June 2009, the date that the Federal Communications Commission (FCC) set. Almost two million households could no longer watch television because they had not prepared for the transition. The switchover had been delayed by the DTV Delay Act. While the majority of the viewers of over-the-air broadcast television in the U.S. watch full-power stations (which number about 1800), there are three other categories of television stations in the U.S.: low-power broadcasting stations, class A stations, and television translator stations. They were given later deadlines. In broadcasting, whatever happens in the United States also influences southern Canada and northern Mexico because those areas are covered by television stations in the U.S.


title: Analog television

text: In Japan, the switch to digital began in northeastern Ishikawa Prefecture on 24 July 2010 and ended in 43 of the country's 47 prefectures (including the rest of Ishikawa) on 24 July 2011, but in Fukushima, Iwate, and Miyagi prefectures, the conversion was delayed to 31 March 2012, due to complications from the 2011 Tōhoku earthquake and tsunami and its related nuclear accidents.


title: Analog television

text: Brazil switched to digital television on 2 December 2007 in its major cities. It is now estimated that Brazil will end analog broadcasting in 2023.


title: Analog television

text: In Malaysia, the Malaysian Communications & Multimedia Commission (MCMC) advertised for tender bids to be submitted in the third quarter of 2009 for the 470 through 742  MHz UHF allocation, to enable Malaysia's broadcast system to move into DTV. The new broadcast band allocation would result in Malaysia's having to build an infrastructure for all broadcasters, using a single digital terrestrial transmission/television broadcast (DTTB) channel. Large portions of Malaysia are covered by television broadcasts from Singapore, Thailand, Brunei, and Indonesia (from Borneo and Batam). Starting from 1 November 2019, all regions in Malaysia were no longer using the analog system after the states of Sabah and Sarawak finally turned it off on 31 October 2019.


title: Analog television

text: In Singapore, digital television under DVB-T2 began on 16 December 2013. The switchover was delayed many times until analog TV was switched off at midnight on 2 January 2019.


title: Analog television

text: In the Philippines, the National Telecommunications Commission required all broadcasting companies to end analog broadcasting on 31 December 2015 at 11:59 p.m. Due to delay of the release of the implementing rules and regulations for digital television broadcast, the target date was moved to 2020. Full digital broadcast is expected in 2021 and all of the analog TV services should be shut down by the end of 2023.


title: Analog television

text: In the Russian Federation, the Russian Television and Radio Broadcasting Network (RTRS) disabled analog broadcasting of federal channels in five stages, shutting down broadcasting in multiple federal subjects at each stage. The first region to have analog broadcasting disabled was Tver Oblast on 3 December 2018, and the switchover was completed on 14 October 2019. During the transition, DVB-T2 receivers and monetary compensations for purchasing of terrestrial or satellite digital TV reception equipment were provided to disabled people, World War II veterans, certain categories of retirees and households with income per member below living wage.


title: Star system

text: A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large group of stars bound by gravitation is generally called a "star cluster" or "galaxy", although, broadly speaking, they are also star systems. Star systems are not to be confused with planetary systems, which include planets and similar bodies (such as comets).


title: Star system

text: A star system of two stars is known as a "binary star", "binary star system" or "physical double star". If there are no tidal effects, no perturbation from other forces, and no transfer of mass from one star to the other, such a system is stable, and both stars will trace out an elliptical orbit around the barycenter of the system indefinitely. "(See Two-body problem)". Examples of binary systems are Sirius, Procyon and Cygnus X-1, the last of which probably consists of a star and a black hole.


title: Star system

text: A multiple star system consists of three or more stars that appear from Earth to be close to one another in the sky. This may result from the stars actually being physically close and gravitationally bound to each other, in which case it is a "physical" multiple star, or this closeness may be merely apparent, in which case it is an "optical" multiple star Physical multiple stars are also commonly called "multiple stars" or "multiple star systems".


title: Star system

text: Most multiple star systems are "triple stars". Systems with four or more components are less likely to occur. Multiple-star systems are called "triple", "ternary", or "trinary" if they contain 3 stars; "quadruple" or "quaternary" if they contain 4 stars; "quintuple" or "quintenary" with 5 stars; "sextuple" or "sextenary" with 6 stars; "septuple" or "septenary" with 7 stars. These systems are smaller than open star clusters, which have more complex dynamics and typically have from 100 to 1,000 stars. Most multiple star systems known are triple; for higher multiplicities, the number of known systems with a given multiplicity decreases exponentially with multiplicity. For example, in the 1999 revision of Tokovinin's catalog of physical multiple stars, 551 out of the 728 systems described are triple. However, because of suspected selection effects, the ability to interpret these statistics is very limited.


title: Star system

text: Most multiple-star systems are organized in what is called a "hierarchical system": the stars in the system can be divided into two smaller groups, each of which traverses a larger orbit around the system's center of mass. Each of these smaller groups must also be hierarchical, which means that they must be divided into smaller subgroups which themselves are hierarchical, and so on. Each level of the hierarchy can be treated as a "two-body problem" by considering close pairs as if they were a single star. In these systems there is little interaction between the orbits and the stars' motion will continue to approximate stable Keplerian orbits around the system's center of mass, unlike the unstable trapezia systems or the even more complex dynamics of the large number of stars in star clusters and galaxies.


title: Star system

text: In a "physical" triple star system, each star orbits the center of mass of the system. Usually, two of the stars form a close binary system, and the third orbits this pair at a distance much larger than that of the binary orbit. This arrangement is called "hierarchical". The reason for this arrangement is that if the inner and outer orbits are comparable in size, the system may become dynamically unstable, leading to a star being ejected from the system. HR 6819 is an example of a physical hierarchical triple system, which has an outer star orbiting an inner physical binary composed of a star and a stellar black hole


title: Star system

text: Triple stars that are "not" all gravitationally bound might comprise a physical binary and an "optical" companion (such as Beta Cephei) or, in rare cases, a purely "optical" triple star (such as Gamma Serpentis).


title: Star system

text: Hierarchical multiple star systems with more than three stars can produce a number of more complicated arrangements. These arrangements can be organized by what Evans (1968) called "mobile diagrams", which look similar to ornamental mobiles hung from the ceiling. Examples of hierarchical systems are given in the figure to the right ("Mobile diagrams"). Each level of the diagram illustrates the decomposition of the system into two or more systems with smaller size. Evans calls a diagram "multiplex" if there is a node with more than two "children", i.e. if the decomposition of some subsystem involves two or more orbits with comparable size. Because, as we have already seen for triple stars, this may be unstable, multiple stars are expected to be "simplex", meaning that at each level there are exactly two "children". Evans calls the number of levels in the diagram its "hierarchy".


title: Star system

text: Higher hierarchies are also possible. Most of these higher hierarchies either are stable or suffer from internal perturbations. Others consider complex multiple stars will in time theoretically disintegrate into less complex multiple stars, like more common observed triples or quadruples are possible.


title: Star system

text: Trapezia are usually very young, unstable systems. These are thought to form in stellar nurseries, and quickly fragment into stable multiple stars, which in the process may eject components as galactic high-velocity stars. They are named after the multiple star system known as the Trapezium Cluster in the heart of the Orion Nebula. Such systems are not rare, and commonly appear close to or within bright nebulae. These stars have no standard hierarchical arrangements, but compete for stable orbits. This relationship is called "interplay". Such stars eventually settle down to a close binary with a distant companion, with the other star(s) previously in the system ejected into interstellar space at high velocities. This dynamic may explain the runaway stars that might have been ejected during a collision of two binary star groups or a multiple system. This event is credited with ejecting AE Aurigae, Mu Columbae and 53 Arietis at above 200 km·s and has been traced to the Trapezium cluster in the Orion Nebula some two million years ago.


title: Star system

text: The components of multiple stars can be specified by appending the suffixes "A", "B", "C", etc., to the system's designation. Suffixes such as "AB" may be used to denote the pair consisting of "A" and "B". The sequence of letters "B", "C", etc. may be assigned in order of separation from the component "A". Components discovered close to an already known component may be assigned suffixes such as "Aa", "Ba", and so forth.


title: Star system

text: A. A. Tokovinin's Multiple Star Catalogue uses a system in which each subsystem in a mobile diagram is encoded by a sequence of digits. In the mobile diagram (d) above, for example, the widest system would be given the number 1, while the subsystem containing its primary component would be numbered 11 and the subsystem containing its secondary component would be numbered 12. Subsystems which would appear below this in the mobile diagram will be given numbers with three, four, or more digits. When describing a non-hierarchical system by this method, the same subsystem number will be used more than once; for example, a system with three visual components, A, B, and C, no two of which can be grouped into a subsystem, would have two subsystems numbered 1 denoting the two binaries AB and AC. In this case, if B and C were subsequently resolved into binaries, they would be given the subsystem numbers 12 and 13.


title: Star system

text: The current nomenclature for double and multiple stars can cause confusion as binary stars discovered in different ways are given different designations (for example, discoverer designations for visual binary stars and variable star designations for eclipsing binary stars), and, worse, component letters may be assigned differently by different authors, so that, for example, one person's "A" can be another's "C". Discussion starting in 1999 resulted in four proposed schemes to address this problem:


title: Star system

text: For a designation system, identifying the hierarchy within the system has the advantage that it makes identifying subsystems and computing their properties easier. However, it causes problems when new components are discovered at a level above or intermediate to the existing hierarchy. In this case, part of the hierarchy will shift inwards. Components which are found to be nonexistent, or are later reassigned to a different subsystem, also cause problems.


title: Star system

text: During the 24th General Assembly of the International Astronomical Union in 2000, the WMC scheme was endorsed and it was resolved by Commissions 5, 8, 26, 42, and 45 that it should be expanded into a usable uniform designation scheme. A sample of a catalog using the WMC scheme, covering half an hour of right ascension, was later prepared. The issue was discussed again at the 25th General Assembly in 2003, and it was again resolved by commissions 5, 8, 26, 42, and 45, as well as the Working Group on Interferometry, that the WMC scheme should be expanded and further developed.


title: Star system

text: The sample WMC is hierarchically organized; the hierarchy used is based on observed orbital periods or separations. Since it contains many visual double stars, which may be optical rather than physical, this hierarchy may be only apparent. It uses upper-case letters (A, B, ...) for the first level of the hierarchy, lower-case letters (a, b, ...) for the second level, and numbers (1, 2, ...) for the third. Subsequent levels would use alternating lower-case letters and numbers, but no examples of this were found in the sample.


title: Pernilla August

text: Pernilla August (; born Mia Pernilla Hertzman-Ericson; 13 February 1958) is a Swedish actress, director and screenwriter. Being one of Sweden's leading actresses and a longtime collaborator with director Ingmar Bergman, she won the Best Actress Award at the 1992 Cannes Film Festival for her role in his "The Best Intentions". She is best known internationally for portraying Shmi Skywalker in "" and "".


title: Pernilla August

text: August started acting during her childhood in theatre and at school. Her professional acting career started in 1975 when director Roy Andersson cast her in a minor role in the film "Giliap" the same year, followed from 1979 by films by other directors, Vilgot Sjöman (among them, the film about Alfred Nobel, 1983) and Lasse Hallström. She studied acting at Swedish National Academy of Mime and Acting in Stockholm 1979–82. Before finishing her studies, she attracted the attention of Ingmar Bergman, who cast her in his film "Fanny and Alexander" (1982), playing the nanny in the director's romanticised portrait of his childhood. That marked the beginning of two decades of collaboration, collecting several international awards, including television series "The Best Intentions" (1991), where she portrayed Bergman's mother and met her second husband to be, director Bille August, and TV-productions "Private Confessions" (1996), directed by Liv Ullmann and Bergman's own "In the Presence of a Clown" (1997).


title: Pernilla August

text: She also starred in Bo Widerberg's "The Serpent's Way" (1986) as well as his TV-production of Henrik Ibsen's "The Wild Duck" (1989). Among the many Scandinavian and international films are also Bille August's "Jerusalem" (1996), Richard Hobert's "Where the Rainbow Ends" (1999) [granted her a Guldbagge Award as Best actress] and "The Birthday" (2000], "I Am Dina" (2002), Björn Runge's "Om jag vänder mig om"/"If I Turn Around" (2003) [a Silver Bear at Berlin International Film Festival 2004 and more Best actress awards], Per Fly's "Manslaughter" (2005), Swedish-Taiwanese "Miss Kicki" (2009) and Jan Troell's "Truth and Consequence" (2012).


title: Pernilla August

text: At the Royal Dramatic Theatre in Stockholm, she has acted in several plays, starting 1981, several directed by Ingmar Bergman and touring internationally. These include Ophelia in William Shakespeare's "Hamlet" (1986) [a part she has also played in another Swedish television film, 1985], August Strindberg's "A Dream Play" (1986), Nora in Henrik Ibsen's "A Doll's House" (1989), Hermione in Bergman's special version of "A Winter's Tale" (1994), the title role in Schiller's "Mary Stuart" (2000) and Helene Alving in Ibsen's "Ghosts" (2002). She also worked with Russian director Jurij Ljubimov in Alexander Pushkin's "A Feast in the Time of Plague" (1996). In 1983-84, she worked at Folkteatern i Gävleborg (The Folk Theatre in Gävleborg) with director Peter Oskarson in Anton Chekhov's "Three Sisters". In 2008, she acted in the stage production of "Steel Magnolias" in Stockholm.


title: Pernilla August

text: She had appeared in two episodes of "The Young Indiana Jones Chronicles" in 1993. Many in the English-speaking world know her best as Shmi Skywalker, the mother of Anakin Skywalker, from "" (1999), and its sequel "Attack of the Clones" (2002). She shared the role as Virgin Mary in "Mary, Mother of Jesus" (1999) with Melinda Kinnaman. She played a significant role in the Swedish film "Sprängaren" (2001) alongside Helena Bergström. In 2011, she reprised her role as Shmi Skywalker in the third season of "" for the episode "Overlords", which aired in 2011. She played the recurring character of Queen Kristina of Sweden in the Netflix series "Young Royals", which premiered in 2021.


title: Pernilla August

text: After her directorial debut with the 2005 short film "Time Bomb" ("Blindgångare"), she debuted as feature-film director and screenwriter in 2010 with "Beyond", starring Noomi Rapace and Ola Rapace. The film was selected as the Swedish entry for the Best Foreign Language Film at the 84th Academy Awards and was much awarded with Swedish Guldbagge Awards and more; August won for Best Director and Best Script. In October 2011, August was asked to direct a new Danish drama series, "Arvingerne", an offer she accepted. The series premiered on DR on 1 January 2014. Her two youngest daughters have cameos in the series.


title: Pernilla August

text: Among many international awards and nominations, at the 1992 Cannes Film Festival she won the award for Best Actress, for her role in Bille August's "The Best Intentions". For the same film she also won the Best Actress award at the 28th Guldbagge Awards.


title: Pernilla August

text: August was born in Stockholm. She has been married twice and changed her name both times. Her first marriage was in 1982 to Klas Östergren, with whom she has one daughter; the marriage ended in divorce in 1989. The second marriage was in 1991 to Bille August, with whom she has two daughters; this marriage also ended in divorce, this time in 1997. She has three daughters: Agnes, Asta, and Alba.


title: Claire Fraser (character)

text: Claire Beauchamp (who adopts the surnames Randall, Fraser, and Grey at various times) is a fictional character in the "Outlander" series of multi-genre novels by American author Diana Gabaldon, and its television adaptation. In the series, Claire is a married World War II nurse visiting Scotland who finds herself transported from 1945 back to 1743. There she finds adventure, war and romance with the dashing Highland warrior Jamie Fraser. Smart, stubborn and willful, Claire uses her wits, practical medical skills and knowledge of the future to survive in the 18th century.


title: Claire Fraser (character)

text: Claire is portrayed by Irish actress Caitríona Balfe in the Starz television series "Outlander". Balfe won a Saturn Award for Best Actress on Television in 2015 and 2016, and a People's Choice Award for Favorite Sci-Fi/Fantasy TV Actress in 2016. She also received nominations for the Golden Globe Award for Best Actress – Television Series Drama in 2015, 2016, 2017 and 2018.


title: Claire Fraser (character)

text: When visiting Scotland, married World War II nurse Claire Randall is transported through time from 1945 back to 1743. There she finds adventure, war and romance with the dashing Highland warrior Jamie Fraser. In the following novels, after the Jacobite defeat at the Battle of Culloden, Claire travels back to her time where she spends 20 years with her former husband Frank Randall, becoming a medical doctor and a surgeon, and raising her and Jamie's daughter Brianna. Finally, having discovered that Jamie survived the Battle of Culloden, she returns to 18th century Scotland and reunites with Jamie. The couple settles in North Carolina, and is soon joined by their daughter Brianna as well as many Scottish settlers.


title: Claire Fraser (character)

text: Gabaldon originally intended "Outlander" to be straight historical fiction, but after a few days of writing Claire she realized that the character did not behave like an 18th century woman. Gabaldon eventually leaned into the modern approach to Claire, which prompted the introduction of time travel. Claire is often described as stubborn and impatient, and she refuses to conform to the 18th century societal expectations of women. Practicing medicine and putting to use her 20th century medical knowledge leads to numerous accusations of witchcraft, including a witch trial.


title: Claire Fraser (character)

text: Balfe won a Saturn Award for Best Actress on Television in 2015 and 2016, and a People's Choice Award for Favorite Sci-Fi/Fantasy TV Actress in 2016. She also received nominations for the Golden Globe Award for Best Actress – Television Series Drama in 2016, 2017, 2018 and 2019.


title: Tim Herlihy

text: Timothy Patrick Herlihy (born October 9, 1966) is an American screen actor, film producer, screenwriter, and Broadway musical bookwriter.


title: Tim Herlihy

text: Films written or produced by Herlihy have grossed over $3 billion at the worldwide box office. He frequently collaborates with Adam Sandler, who played a "Saturday Night Live" character, "The Herlihy Boy", in honor of Tim Herlihy.


title: Tim Herlihy

text: Herlihy was born in Brooklyn, New York, and raised in Poughkeepsie, New York. His father was a New York City firefighter. He graduated from Arlington High School in 1984.


title: Tim Herlihy

text: While majoring in accounting and international business at New York University, he roomed with Adam Sandler in the Brittany Hall dormitory. When Sandler began doing stand-up comedy during their sophomore year, Herlihy wrote material for Sandler.


title: Tim Herlihy

text: After graduating in 1988, Herlihy spent a year as an accountant at Ernst & Young in Manhattan before attending the New York University School of Law. Herlihy continued to collaborate with Sandler, who had recently been hired at "Saturday Night Live". After law school, Herlihy worked as a securities lawyer at Cahill Gordon & Reindel in Lower Manhattan.


title: Tim Herlihy

text: While working as an attorney, Herlihy continued collaborating with Sandler on "SNL" sketches, including Canteen Boy. They also began working on a screenplay for "Billy Madison", which Herlihy wrote at his law firm late at night.


title: Tim Herlihy

text: Herlihy was hired as a writer at "Saturday Night Live" in March of 1994. He remained at the show after Sandler left in 1995, rising to head writer and eventually producer. He wrote many political sketches leading up to the 1996 Presidential election, and co-wrote (with Tina Fey) the 1999 sketch in which Monica Lewinsky appeared. He left the show in 1999 to focus on film work.


title: Tim Herlihy

text: He wrote or co-wrote the Sandler films "Billy Madison" (1995), "Happy Gilmore" (1996), "The Wedding Singer" (1998), "The Waterboy" (1998), "Big Daddy" (1999) and "Pixels" (2015).


title: Tim Herlihy

text: In 1999, Herlihy appeared in the film "Big Daddy" as the "Singing Kangaroo," and sang "The Kangaroo Song" on the film's soundtrack.


title: Tim Herlihy

text: Herlihy has written for and or performed on three of Sandler's comedy albums: "They're All Gonna Laugh at You!" (1993), "What the Hell Happened to Me?" (1996) and "Shhh...Don't Tell" (2004).


title: Tim Herlihy

text: In 2006, Herlihy co-wrote the book and two songs for a Broadway musical version of "The Wedding Singer". It opened at the Al Hirschfeld Theatre on April 27, 2006 and closed on December 31, 2006 after 284 performances. Herlihy's and Chad Beguelin's book was nominated for the 2006 Tony Award for Best Book of a Musical, and the show itself was nominated for the Tony Award for Best Musical. It subsequently has had many international productions.


title: Tim Herlihy

text: In 2015, Herlihy co-wrote (with Sandler) the Western comedy film "The Ridiculous 6", distributed by Netflix. Despite being universally panned by critics, on January 6, 2016, it was announced by Netflix that the film had been viewed more times in 30 days than any other movie in Netflix history.


title: Tim Herlihy

text: Herlihy returned to "Saturday Night Live" for one episode in 2015, to work with Tracy Morgan on a recurring sketch they had created in the 1990s, Brian Fellow's Safari Planet. The episode was nominated for an Emmy Award for outstanding writing, and won a Writers Guild Award for Outstanding Writing for a Comedy/Variety sketch series.


title: Tim Herlihy

text: Herlihy's son, Martin, also attended New York University. Martin currently writes for "Saturday Night Live" as part of the comedy trio Please Don't Destroy, which also includes John Higgins, the son of "Saturday Night Live" writer Steve Higgins.


title: Royal Rumble (2002)

text: The 2002 Royal Rumble was the 15th annual Royal Rumble professional wrestling pay-per-view (PPV) event produced by the World Wrestling Federation (WWF, now WWE). It took place on January 20, 2002, at the Philips Arena in Atlanta, Georgia. It was the final Royal Rumble event produced under the WWF name, as in May, the WWF was renamed to World Wrestling Entertainment (WWE). It was also the final Royal Rumble held before the introduction of the first brand extension in March. Six matches were contested at the event.


title: Royal Rumble (2002)

text: As has been customary since 1993, the Royal Rumble match winner received a world championship match at that year's WrestleMania. For the 2002 event, the winner received a match for the Undisputed WWF Championship at WrestleMania X8—this was the last Royal Rumble until 2014 to feature one world championship. The main event was the 2002 Royal Rumble match, which was won by Triple H, who last eliminated Kurt Angle. In other prominent matches, Chris Jericho defeated The Rock to retain the Undisputed WWF Championship, Ric Flair defeated Vince McMahon in a Street Fight, and William Regal defeated Edge to win the WWF Intercontinental Championship.


title: Royal Rumble (2002)

text: The Royal Rumble is an annual gimmick pay-per-view (PPV), produced every January by the World Wrestling Federation (WWF, now WWE) since 1988. It is one of the promotion's original four pay-per-views, along with WrestleMania, SummerSlam, and Survivor Series, which were dubbed the "Big Four", and was considered one of the "Big Five" PPVs, along with King of the Ring. It is named after the Royal Rumble match, a modified battle royal in which the participants enter at timed intervals instead of all beginning in the ring at the same time. The 2002 event was the 15th event in the Royal Rumble chronology and was scheduled to be held on January 20, 2002, at the Philips Arena in Atlanta, Georgia.


title: Royal Rumble (2002)

text: The Royal Rumble match generally features 30 wrestlers. Traditionally, the winner of the match earns a world championship match at that year's WrestleMania. For 2002, the winner earned a match for the Undisputed WWF Championship at WrestleMania X8, following the unification of the WWF Championship and (WCW) World Championship as the Undisputed WWF Championship at Vengeance in December 2001.


title: Royal Rumble (2002)

text: The card consisted of six matches. The matches resulted from scripted storylines, where wrestlers portrayed heroes, villains, or less distinguishable characters to build tension and culminated in a wrestling match or series of matches. Results were predetermined by WWF's writers, with storylines produced on their weekly television shows, "Raw" and "SmackDown".


title: Royal Rumble (2002)

text: The main feud was between Chris Jericho and The Rock for Jericho's Undisputed WWF Championship. The feud, which had begun in October 2001 while the two were members of Team WWF during the InVasion and traded the WCW Championship between them, continued at Vengeance, when Jericho defeated both The Rock and the reigning WWF Champion Stone Cold Steve Austin to unify the titles. On the following night's episode of "Raw", Jericho successfully defended the Undisputed title over Stone Cold Steve Austin in a Steel cage match with help from Booker T. During the following two weeks, Jericho had successfully defended the title against the likes of Rob Van Dam, The Big Show, and Kurt Angle. The Rock earned a match for the Undisputed WWF Championship at the Royal Rumble on the January 3 episode of "SmackDown!" by defeating Booker T. On the January 10 episode of "SmackDown!", The Rock and Rob Van Dam defeated Jericho and Test when The Rock made Jericho submit with the Sharpshooter.


title: Royal Rumble (2002)

text: The secondary feud was between the two WWF Co-Owners Ric Flair and Vince McMahon. The feud all started on the November 19 episode of "Raw", when Flair made his return to the WWF and revealed that he has bought Shane and Stephanie's stock to the WWF which now means that he and Vince were partners that own the company. On the December 27th episode of "SmackDown!", McMahon came to the ring to share his new years resolutions when he was interrupted by Flair. Flair reminded Vince how he had hired him to come to the WWF when he was under contract with NWA back in 1988 until Flair left NWA and came to the WWF and how he had won the 1992 Royal Rumble match and became WWF Champion. Flair also brought up his main event match with "Macho Man" Randy Savage at WrestleMania VIII. Flair then claimed that he looked through all the contracts one of which he pulled out that said "Vince McMahon Owner-Wrestler" which meant that Vince would wrestle at Royal Rumble. McMahon asked who got the balls to step into the ring with him and Flair punched Vince in the mouth and announced that the two of them would face each other at the Royal Rumble. The following week, Flair announced that the match would be a Street Fight which Vince agreed to. The next four weeks saw Flair and McMahon confronting each other in the build up to their match which includes McMahon mocking Flair by putting on a blonde wig and his blue robe and also assaulting him with a lead pipe. During an interview, McMahon says he loves destroying lives and promised to destroy Flair's life at Royal Rumble.


title: Royal Rumble (2002)

text: On the January 7 episode of "Raw", buildup towards the Royal Rumble match started, with Austin saying he wanted to enter. Later that night, Triple H made his return after missing nearly eight months with an injury and announced that he too would be entering the Royal Rumble match. He was interrupted by Kurt Angle, who then announced his intentions to enter the match, which was to be his first, and mentioned his victory over Triple H at the previous year's Royal Rumble event when he was the reigning WWF Champion. Triple H performed a Pedigree on Angle in retaliation. During a match between Austin and Angle on the January 10 episode of "SmackDown!", Kane, The Big Show, and Triple H all interfered. In the end, only Triple H remained standing, until The Undertaker stared him down from the top of the ramp. On the January 14 episode of "Raw", Triple H stated that he wants to win the Undisputed WWF Championship. Austin came out, and they fought until The Undertaker came out, and hit Triple H with a chair, allowing Austin to hit the Stone Cold Stunner. The Undertaker then hit Austin with the chair. On the January 17 episode of "SmackDown!", Austin and Triple H defeated Angle and Booker T. After the match, The Undertaker again came out, and stared them down.


title: Royal Rumble (2002)

text: The feud between Edge and William Regal continued from Vengeance. On the December 10 episode of "Raw", Edge mocked Regal, prompting Regal to nail him from behind with brass knuckles. On the December 13 episode of "SmackDown!", William Regal and Kurt Angle faced Edge and Rikishi in a tag match. After the match, Edge hit Regal with a steel chair and an Edgecution onto the chair, breaking his nose, and causing him to bleed. On the January 7 episode of "Raw", Regal interfered after Edge's victory over Lance Storm and hit him with brass knuckles. Regal challenged Edge to a match for the WWF Intercontinental Championship at the Royal Rumble, and Edge accepted. On the January 14 episode of "Raw", Edge and Rob Van Dam faced William Regal and Test, where Regal pinned Edge after using the brass knuckles. On the January 17 episode of "SmackDown!", Regal defeated Rob Van Dam when he used brass knuckles behind the referee's back. Later on the night, Regal came out during Edge's match with Test but failed to interfere when Edge nailed him and referee Nick Patrick with a chair.


title: Royal Rumble (2002)

text: The first match was between Spike Dudley and Tazz, and the Dudley Boyz (Bubba Ray Dudley and D-Von Dudley) for the WWF Tag Team Championship. The Dudley Boyz dominated Spike in the beginning with Bubba Ray ripping off Spike's neck brace. Spike fought back by performing a Dudley Dog but failed to capitalize. The Dudley Boyz then double-teamed Spike while the referee was preoccupied with Tazz. Tazz eventually came in, and both dominated. Stacy Keibler, who accompanied the Dudley Boyz, climbed on the apron, and attempted to distract Tazz and Tazz locked in the Tazzmission until Devon broke the hold. Spike


title: Royal Rumble (2002)

text: hit the Dudley Dog on Bubba and attempted to do the same on Devon but Spike was thrown out of the ring, Devon then ran at Tazz in the corner which was dodged, Tazz then applied the Tazzmission to retain the title.


title: Royal Rumble (2002)

text: The second match was between Edge and William Regal for the WWF Intercontinental Championship. Before the match, the referee found brass knuckles in Regal's tights, and confiscated them. The match went back and forth until Regal knocked Edge out of the ring. Regal applied the Regal Stretch, but Edge reached the ropes to break the hold. Edge attempted a spear, but Regal pushed the referee to receive the move. Regal took out another pair of brass knuckles and hit Edge with them. The referee recovered to count the pinfall for Regal to win the title.


title: Royal Rumble (2002)

text: The third match was between Trish Stratus and Jazz for the WWF Women's Championship with Jacqueline as Special Guest Referee. Jazz had the early advantage, focusing on Stratus' injured hand. Jazz then confronted Jacqueline, and they shoved each other. Stratus attempted a bulldog but Jazz countered with a roll-up, and executed a snap DDT. Stratus blocked an attack in the corner, and delivered a bulldog to win the match, and retained the title.


title: Royal Rumble (2002)

text: The fourth match was a Street Fight between Ric Flair and Vince McMahon. Flair gained the early advantage with punches and knife edge chops. McMahon attacked him with weapons, and sent him into the ringpost and steps. McMahon applied the figure four leglock, but Flair reversed it. McMahon reached the ropes, and went outside the ring. Flair hit McMahon with a low blow, a television monitor and a lead pipe. Flair forced McMahon to submit to the figure four leglock to win the match.


title: Royal Rumble (2002)

text: The fifth match was between Chris Jericho and The Rock for the Undisputed WWF Championship. The Rock quickly took control of the match and got a near-fall following a samoan drop; until Jericho regained control, and removed the padding off one of the turnbuckles. Jericho attempted the Walls of Jericho, but The Rock escaped. Jericho continued his control until The Rock delivered a superplex, and a snap overhead belly to belly suplex. Jericho retaliated with two Lionsaults. The Rock then countered a missile dropkick, and applied the Sharpshooter. Lance Storm and Christian distracted the referee as Jericho submitted. As The Rock disposed of them, Jericho took advantage and executed a Rock Bottom and attempted a People's Elbow, but The Rock avoided it and threw Jericho out of the ring. Jericho tried to hit a Rock Bottom through the Spanish announce table, but The Rock countered and executed a Rock Bottom through the English announce table. Back in the ring, The Rock covered Jericho for a near-fall. Jericho countered a Rock Bottom and applied the Walls of Jericho, but The Rock reached the ropes and rolled Jericho up for a near-fall on the second attempt. The Rock accidentally hit the referee and Jericho hit The Rock with the WWF title belt. Jericho signaled Nick Patrick (a heel referee) to come out, and referee. The Rock executed a DDT, but Patrick refused to count the pinfall. The Rock attacked Patrick with a Rock Bottom, and executed a Spinebuster and a People's Elbow on Jericho. As The Rock tried to revive the original referee; Earl Hebner, Jericho again took advantage and hit a low blow, and sent The Rock into the exposed turnbuckle. Jericho pinned The Rock with a roll-up using the ropes as leverage to retain the title.