Videotape
Videotape is magnetic tape used for storing video and sound in addition. Information stored can be in the form of either digital signal. Videotape is used in both video tape recorders or, more videocassette recorders and camcorders. Videotapes are used for storing scientific or medical data, such as the data produced by an electrocardiogram; because video signals have a high bandwidth, stationary heads would require high tape speeds, in most cases, a helical-scan video head rotates against the moving tape to record the data in two dimensions. Tape is a linear method of storing information and thus imposes delays to access a portion of the tape, not under the heads; the early 2000s saw the introduction and rise to prominence of high quality random-access video recording media such as hard disks and flash memory. Since videotape has been relegated to archival and similar uses; the electronics division of entertainer Bing Crosby's production company, Bing Crosby Enterprises, gave the world's first demonstration of a videotape recording in Los Angeles on November 11, 1951.
Developed by John T. Mullin and Wayne R. Johnson since 1950, the device gave what were described as "blurred and indistinct" images using a modified Ampex 200 tape recorder and standard quarter-inch audio tape moving at 360 inches per second. A year an improved version using one-inch magnetic tape was shown to the press, who expressed amazement at the quality of the images although they had a "persistent grainy quality that looked like a worn motion picture". Overall the picture quality was still considered inferior to the best kinescope recordings on film. Bing Crosby Enterprises hoped to have a commercial version available in 1954 but none came forth; the BBC experimented from 1952 to 1958 with a high-speed linear videotape system called VERA, but this was unfeasible. It used half-inch tape on 20-inch reels traveling at 200 inches per second. RCA demonstrated the magnetic tape recording of both black-and-white and color television programs at its Princeton laboratories on December 1, 1953.
The high-speed longitudinal tape system, called Simplex, in development since 1951, could record and play back only a few minutes of a television program. The color system used half-inch tape on 10-1/2 inch reels to record five tracks, one each for red, green and audio; the black-and-white system used quarter-inch tape on 10-1/2 inch reels with two tracks, one for video and one for audio. Both systems ran at 360 inches per second with 2,500 feet on a reel. RCA-owned NBC first used it on The Jonathan Winters Show on October 23, 1956 when a prerecorded song sequence by Dorothy Collins in color was included in the otherwise live television program. In 1953, Dr. Norikazu Sawazaki developed a prototype helical scan video tape recorder. BCE demonstrated a color system in February 1955 using a longitudinal recording on half-inch tape. CBS, RCA's competitor, was about to order BCE machines when Ampex introduced the superior Quadruplex system. BCE was acquired by 3M Company in 1956. In 1959, Toshiba released the first commercial helical scan video tape recorder.
The first commercial professional broadcast quality videotape machines capable of replacing kinescopes were the two-inch quadruplex videotape machines introduced by Ampex on April 14, 1956 at the National Association of Broadcasters convention in Chicago. Quad employed a transverse four-head system on a two-inch tape, stationary heads for the sound track. CBS Television first used the Ampex VRX-1000 Mark IV at its Television City studios in Hollywood on November 30, 1956 to play a delayed broadcast of Douglas Edwards and the News from New York City to the Pacific Time Zone. On January 22, 1957, the NBC Television game show Truth or Consequences, produced in Hollywood, became the first program to be broadcast in all time zones from a prerecorded videotape. Ampex introduced a color videotape recorder in 1958 in a cross-licensing agreement with RCA, whose engineers had developed it from an Ampex black-and-white recorder. NBC's special, An Evening With Fred Astaire, is the oldest surviving television network color videotape, has been restored by the UCLA Film and Television Archive.
On December 7, 1963, instant replay was used for the first time during the live transmission of the Army–Navy Game by its inventor, director Tony Verna. Although Quad became the industry standard for thirty years, it has drawbacks such as an inability to freeze pictures, no picture search. In early machines, a tape could reliably be played back using only the same set of hand-made tape heads, which wore out quickly. Despite these problems, Quad is capable of producing excellent images. Subsequent videotape systems have used helical scan, where the video heads record diagonal tracks onto the tape. Many early videotape recordings were not preserved. While much less expensive and more convenient than kinescope, the high cost of 3M Scotch 179 and other early videotapes meant that most broadcasters erased and reused them, regarded videotape as a better and more cost-effective means of time-delaying broadcasts than kinescopes, it was the four time zones of the continental United States which had made the system desirable in the first place.
However, some classic television programs recorded on studio videotape still exist, are available on DVD – among them NBC's Peter Pan with Mary Martin as Peter, several episodes o
Tape transport
A tape transport is the collection of parts of a magnetic tape player or recorder that the actual tape passes through. Transport parts include the head, pinch roller, tape pins, tape guide; the tape transport as a whole is called the transport mechanism. The capstan is a rotating spindle used to move recording tape through the mechanism of a tape recorder; the tape is threaded between the capstan and one or more rubber-covered wheels, called pinch rollers, which press against the capstan, thus providing friction necessary for the capstan to pull the tape. The capstan is always placed downstream from the tape heads. To maintain the required tension against the tape heads and other part of the tape transport, a small amount of drag is placed on the supply reel. Tape recorder capstans have a function similar to nautical capstans, which however have no pinch rollers, the line being wound around them; the use of a capstan allows the tape to run at a constant speed. Capstans are precision-machined spindles, polished smooth: any out-of-roundness or imperfections can cause uneven motion and an audible effect called flutter.
The alternative to capstan drive driving the tape takeup reel, causes problems both with the speed difference between a full and empty reel and with speed variations as described. Dual capstans, where one is on each side of the heads, are claimed to provide smoother tape travel across the heads and result in less variance in the recorded/playback signal; the pinch roller is a rubberized, free-spinning wheel used to press magnetic tape against a capstan shaft in order to create friction necessary to drive the tape along the magnetic heads. Most magnetic tape recorders use one capstan motor and one pinch roller located after the magnetic heads in the direction of the moving tape; however multiple pinch rollers may be employed in association with one or more capstans. An example of the application of multiple pinch rollers is the Technics-RS1520 tape recorder, which utilizes two pinch rollers located on opposite sides of a single capstan shaft, providing a more stable transport across two sets of magnetic heads.
Dual pinch rollers are used in auto-reverse cassette decks to drive the tape in both directions as needed. In this case, only one pinch roller is pressed against its corresponding capstan at a time. A tension arm is a device used in magnetic tape recorders/reproducers to control the tension of the magnetic tape during machine operation; the recorders equipped with a tension arm can utilize more than one of them to control tape tension in different direction of winding or during different modes of tape operation. Tension arms can be found on digital data recorders and other types of recorders/reproducers using continuous tape media such as magnetic digital tape, perforated paper tape, analog magnetic tape. One of many US Patents pertaining to Tension arm Workbench Guide to Tape Recorder Servicing. G. Howard Poteet, 1977
Magnetic tape
Magnetic tape is a medium for magnetic recording, made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders respectively. A device that stores computer data on magnetic tape is known as a tape drive. Magnetic tape revolutionized reproduction and broadcasting, it allowed radio, which had always been broadcast live, to be recorded for or repeated airing. It allowed gramophone records to be recorded in multiple parts, which were mixed and edited with tolerable loss in quality, it was a key technology in early computer development, allowing unparalleled amounts of data to be mechanically created, stored for long periods, accessed. In recent decades, other technologies have been developed that can perform the functions of magnetic tape. In many cases, these technologies have replaced tape. Despite this, innovation in the technology continues, Sony and IBM continue to produce new magnetic tape drives.
Over time, magnetic tape made in the 1970s and 1980s can suffer from a type of deterioration called sticky-shed syndrome. It can render the tape unusable; the oxide side of a tape is the surface. This is the side that stores the information, the opposite side is a substrate to give the tape strength and flexibility; the name originates from the fact that the magnetic side of most tapes is made of iron oxide, though chromium is used for some tapes. An adhesive binder between the oxide and the substrate holds the two sides together. In all tape formats, a tape drive uses motors to wind the tape from one reel to another, passing over tape heads to read, write or erase as it moves. Magnetic tape was invented for recording sound by Fritz Pfleumer in 1928 in Germany, based on the invention of magnetic wire recording by Oberlin Smith in 1888 and Valdemar Poulsen in 1898. Pfleumer's invention used a ferric oxide powder coating on a long strip of paper; this invention was further developed by the German electronics company AEG, which manufactured the recording machines and BASF, which manufactured the tape.
In 1933, working for AEG, Eduard Schuller developed the ring-shaped tape head. Previous head designs were tended to shred the tape. Another important discovery made in this period was the technique of AC biasing, which improved the fidelity of the recorded audio signal by increasing the effective linearity of the recording medium. Due to the escalating political tensions, the outbreak of World War II, these developments in Germany were kept secret. Although the Allies knew from their monitoring of Nazi radio broadcasts that the Germans had some new form of recording technology, its nature was not discovered until the Allies acquired captured German recording equipment as they invaded Europe at the end of the war, it was only after the war that Americans Jack Mullin, John Herbert Orr, Richard H. Ranger, were able to bring this technology out of Germany and develop it into commercially viable formats. A wide variety of recorders and formats have been developed since, most reel-to-reel and Compact Cassette.
The practice of recording and editing audio using magnetic tape established itself as an obvious improvement over previous methods. Many saw the potential of making the same improvements in recording the video signals used by television. Video signals use more bandwidth than audio signals. Existing audio tape recorders could not capture a video signal. Many set to work on resolving this problem. Jack Mullin and the BBC both created crude working systems that involved moving the tape across a fixed tape head at high speeds. Neither system saw much use, it was the team at Ampex, led by Charles Ginsburg, that made the breakthrough of using a spinning recording head and normal tape speeds to achieve a high head-to-tape speed that could record and reproduce the high bandwidth signals of video. The Ampex system was called Quadruplex and used 2-inch-wide tape, mounted on reels like audio tape, which wrote the signal in what is now called transverse scan. Improvements by other companies Sony, led to the development of helical scan and the enclosure of the tape reels in an easy-to-handle videocassette cartridge.
Nearly all modern videotape systems use helical cartridges. Videocassette recorders used to be common in homes and television production facilities, but many functions of the VCR have been replaced with more modern technology. Since the advent of digital video and computerized video processing, optical disc media and digital video recorders can now perform the same role as videotape; these devices offer improvements like random access to any scene in the recording and the ability to pause a live program and have replaced videotape in many situations. Magnetic tape was first used to record computer data in 1951 on the Eckert-Mauchly UNIVAC I; the system's UNISERVO I tape drive used a thin strip of one half inch wide metal, consisting of nickel-plated bronze. Recording density was 100 characters per inch on eight tracks. Early IBM 7 track tape drives were floor-standing and used vacuum columns to mechanically buffer long U-shaped loops of tape; the two tape reels visibly fed tape through the columns, intermittently spinning the reels in rapid, unsynchronized bursts, resulting in visually striking action.
Stock shots of such vacuum-column tape drives in motion were used to represent "the computer" in movies and televis
United States dollar
The United States dollar is the official currency of the United States and its territories per the United States Constitution since 1792. In practice, the dollar is divided into 100 smaller cent units, but is divided into 1000 mills for accounting; the circulating paper money consists of Federal Reserve Notes that are denominated in United States dollars. Since the suspension in 1971 of convertibility of paper U. S. currency into any precious metal, the U. S. dollar is, de facto, fiat money. As it is the most used in international transactions, the U. S. dollar is the world's primary reserve currency. Several countries use it as their official currency, in many others it is the de facto currency. Besides the United States, it is used as the sole currency in two British Overseas Territories in the Caribbean: the British Virgin Islands and Turks and Caicos Islands. A few countries use the Federal Reserve Notes for paper money, while still minting their own coins, or accept U. S. dollar coins. As of June 27, 2018, there are $1.67 trillion in circulation, of which $1.62 trillion is in Federal Reserve notes.
Article I, Section 8 of the U. S. Constitution provides that the Congress has the power "To coin money". Laws implementing this power are codified at 31 U. S. C. § 5112. Section 5112 prescribes the forms; these coins are both designated in Section 5112 as "legal tender" in payment of debts. The Sacagawea dollar is one example of the copper alloy dollar; the pure silver dollar is known as the American Silver Eagle. Section 5112 provides for the minting and issuance of other coins, which have values ranging from one cent to 100 dollars; these other coins are more described in Coins of the United States dollar. The Constitution provides that "a regular Statement and Account of the Receipts and Expenditures of all public Money shall be published from time to time"; that provision of the Constitution is made specific by Section 331 of Title 31 of the United States Code. The sums of money reported in the "Statements" are being expressed in U. S. dollars. The U. S. dollar may therefore be described as the unit of account of the United States.
The word "dollar" is one of the words in the first paragraph of Section 9 of Article I of the Constitution. There, "dollars" is a reference to the Spanish milled dollar, a coin that had a monetary value of 8 Spanish units of currency, or reales. In 1792 the U. S. Congress passed a Coinage Act. Section 9 of that act authorized the production of various coins, including "DOLLARS OR UNITS—each to be of the value of a Spanish milled dollar as the same is now current, to contain three hundred and seventy-one grains and four sixteenth parts of a grain of pure, or four hundred and sixteen grains of standard silver". Section 20 of the act provided, "That the money of account of the United States shall be expressed in dollars, or units... and that all accounts in the public offices and all proceedings in the courts of the United States shall be kept and had in conformity to this regulation". In other words, this act designated the United States dollar as the unit of currency of the United States. Unlike the Spanish milled dollar, the U.
S. dollar is based upon a decimal system of values. In addition to the dollar the coinage act established monetary units of mill or one-thousandth of a dollar, cent or one-hundredth of a dollar, dime or one-tenth of a dollar, eagle or ten dollars, with prescribed weights and composition of gold, silver, or copper for each, it was proposed in the mid-1800s that one hundred dollars be known as a union, but no union coins were struck and only patterns for the $50 half union exist. However, only cents are in everyday use as divisions of the dollar. XX9 per gallon, e.g. $3.599, more written as $3.599⁄10. When issued in circulating form, denominations equal to or less than a dollar are emitted as U. S. coins while denominations equal to or greater than a dollar are emitted as Federal Reserve notes. Both one-dollar coins and notes are produced today, although the note form is more common. In the past, "paper money" was issued in denominations less than a dollar and gold coins were issued for circulation up to the value of $20.
The term eagle was used in the Coinage Act of 1792 for the denomination of ten dollars, subsequently was used in naming gold coins. Paper currency less than one dollar in denomination, known as "fractional currency", was sometimes pejoratively referred to as "shinplasters". In 1854, James Guthrie Secretary of the Treasury, proposed creating $100, $50 and $25 gold coins, which were referred to as a "Union", "Half Union", "Quarter Union", thus implying a denomination of 1 Union = $100. Today, USD notes are made from cotton fiber paper, unlike most common paper, made of wood fiber. U. S. coins are produced by the United States Mint. U. S. dollar banknotes are printed by the Bureau of Engraving and Printing and, since 1914, have been issued by t
Helical scan
Helical scan is a method of recording high-frequency signals on magnetic tape. It is used in open-reel video tape recorders, video cassette recorders, digital audio tape recorders, some computer tape drives. In a fixed tape head recording system, magnetic tape is drawn past the head at a constant speed; the head creates a fluctuating magnetic field in response to the signal to be recorded, the magnetic particles on the tape are forced to line up with the field at the head. As the tape moves away, the magnetic particles carry an imprint of the signal in their magnetic orientation. If the tape moves too a high-frequency signal will not be imprinted: the particles' polarity will oscillate in the vicinity of the head, to be left in a random position, thus the bandwidth channel capacity of the recorded signal can be seen to be related to tape speed: the faster the speed, the higher the frequency that can be recorded. Video needs more bandwidth than audio, so much so that tape would have to be drawn past the heads at high speed to capture this signal.
This is impractical, since tapes of immense length would be required: VERA, developed by the BBC between 1952 and 1958, used 52cm reels running at a speed of 5.08 m/s, could only record about 15 minutes of 405-line monochrome programme. The adopted solution is to rotate the head against the tape at high speed, so that the relative velocity is high, but the tape itself moves at a slow speed. To accomplish this, the head carrier must be tilted so that at each rotation of the drum, a new area of tape passes the head; each segment of the signal is recorded as a diagonal stripe across the tape. This is known as a helical scan because the tape wraps around the circular drum at an angle, traveling up like a helix; the difference between the head writing speed and linear tape speed is vast: for example, 580 centimetres per second versus 3.5 cm/s. With the advent of television broadcasting in Japan in the early 1950s, they saw the need for magnetic television signal recording. Dr. Norikazu Sawazaki developed a prototype helical scan recorder in 1953.
Independently in Germany, Eduard Schüller was developing a helical scan method of recording. When Ampex developed the quadruplex magnetic tape video recording system in 1956, it had certain limitations the most important of, the lack of pause or still frame capability, because the picture signal was segmented, or broken down into discrete segments to be recorded on the tape individually. Thus, when tape motion was stopped, only a single segment of the picture recording was present at the playback heads; the helical-scan system overcame this limitation. Toshiba introduced helical-scan technology to the television industry in 1959. During the 1960s and 1970s, helical-scan recording machines were introduced by many manufacturers and marketed all over the world; the technology took over the market for video recording, due to its reduced complexity, greater reliability, lower manufacturing and servicing costs, lighter weight, lower energy consumption, more versatile features, when compared to the quadruplex system.
These factors made it possible to bring video recording to users at home, in a cassette format. There were a number of problems to be overcome with this system; the high tape/head speed could lead to rapid wear of both the tape and the head, so both need to be polished, the head made of a hard, wear-resistant material. Most systems operate with an air bearing separating the heads from the surface of the drum. Supplying signals to a rotating head is problematic: This is accomplished by coupling the signal inductively through a rotary transformer; the transport mechanism is much more complex than a fixed head system, since during loading, the tape must be pulled around a rotating drum containing the head. In a VCR for example, the tape must be pulled out of the cassette case and threaded around the drum, between the capstan and pinch roller; this leads to complex and unreliable mechanics. Two transport systems evolved in the early video machines, known as the alpha wrap and the omega wrap. In the alpha-wrap machines the tape is wrapped around the head drum for a full 360 degrees.
There is only one head. This system has problems when the head transits from one piece of tape to the next, giving a large signal gap between fields; the machine has to fill this gap with the frame-synchronizing pulses. Such machines are constrained to using guard-band recording. In the omega-wrap machines, the tape is only wrapped around the head for 180 degrees. Two video heads are required, each writing alternate fields; this system has a much smaller signal gap between fields, but the frame-synchronizing pulses are able to be recorded on the tape. Cassette-based systems can only utilize the omega-wrap technique, since it is impractical for an automatic loading system to introduce a loop into the tape. Early omega-wrap systems utilize guard-band recording, but the presence of two heads permits the development of the slant-azimuth technique. Developments use increasing numbers of heads to record video using smaller drums and for recording HiFi sound as well. A variation of the omega wrap, such as that used by Echo Science Corporation of Mountain View, California in its instrumentation and high resolution video recorders in the late 1970s and 1980s, wraps the 1-inch tape about 190 degrees around the two-headed drum, so there is signal overlap between the two heads.
Head switching in video recorders occurs instantan
Cassette tape
The Compact Cassette, Compact Audio Cassette or Musicassette commonly called the cassette tape or tape or cassette, is an analog magnetic tape recording format for audio recording and playback. It was developed by Philips in Hasselt and released in 1962. Compact cassettes come in two forms, either containing content as a prerecorded cassette, or as a recordable "blank" cassette. Both forms are reversible by the user; the compact cassette technology was designed for dictation machines, but improvements in fidelity led the Compact Cassette to supplant the Stereo 8-track cartridge and Reel-to-reel tape recording in most non-professional applications. Its uses ranged from portable audio to home recording to data storage for early microcomputers; the first cassette player designed for use in car dashboards was introduced in 1968. Between the early 1970s and the early 2000s, the cassette was one of the two most common formats for prerecorded music, first alongside the LP record and the compact disc.
Compact Cassettes contain two miniature spools, between which the magnetically coated, polyester-type plastic film is passed and wound. These spools and their attendant parts are held inside a protective plastic shell, 4 by 2.5 by 0.5 inches at its largest dimensions. The tape itself was referred to as "eighth-inch" tape 1⁄8 inches wide, but it was larger: 0.15 inches. Two stereo pairs of tracks or two monaural audio tracks are available on the tape; this reversal is achieved either by flipping the cassette, or by the reversal of tape movement when the mechanism detects that the tape has come to an end. In 1935, decades before the introduction of the Compact Cassette, AEG released the first reel-to-reel tape recorder, with the commercial name "Magnetophon", it was based on the invention of the magnetic tape by Fritz Pfleumer, which used similar technology but with open reels. These instruments were expensive and difficult to use and were therefore used by professionals in radio stations and recording studios.
In 1958, following four years of development, RCA Victor introduced the stereo, quarter-inch, reel-to-reel RCA tape cartridge. However, it was a large cassette, offered few pre-recorded tapes. Despite the multiple versions, it failed. Consumer use of magnetic tape machines took off in the early 1960s, after playback machines reached a comfortable, user-friendly design; this was aided by the introduction of transistors which replaced the bulky and costly vacuum tubes of earlier designs. Reel-to-reel tape became more suitable to household use, but still remained an esoteric product. WIRAG, the Vienna division of Philips developed a cartridge, described as single-hole cassette, adapted from its German described name Einloch-Kassette. Tape and tape speed were identical with the Compact Cassette. Grundig came up with the DC-International derived from blue prints of the Compact Cassette in 1965, but failed on the demand of distributing companies. In 1962, Philips invented the Compact Cassette medium for audio storage, introducing it in Europe on 30 August 1963 at the Berlin Radio Show, in the United States in November 1964, with the trademark name Compact Cassette.
The team at Philips was led by Lou Ottens in Hasselt, Belgium."Philips was competing with Telefunken and Grundig in a race to establish its cassette tape as the worldwide standard, it wanted support from Japanese electronics manufacturers." However, the Philips' Compact Cassette became dominant as a result of Philips' decision to license the format free of charge. Philips released the Norelco Carry-Corder 150 recorder/player in the US in November 1964. By 1966 over 250,000 recorders had been sold in the US alone and Japan soon became the major source of recorders. By 1968, 85 manufacturers had sold over 2.4 million players. By the end of the 1960s, the cassette business was worth an estimated 150 million dollars. In the early years sound quality was mediocre, but it improved by the early 1970s when it caught up with the quality of 8-track tape and kept improving; the Compact Cassette went on to become a popular alternative to the 12-inch vinyl LP during the late 1970s. The mass production of "blank" Compact Cassettes began in 1964 in Germany.
Prerecorded music cassettes were launched in Europe in late 1965. The Mercury Record Company, a US affiliate of Philips, introduced M. C. to the US in July 1966. The initial offering consisted of 49 titles. However, the system had been designed for dictation and portable use, with the audio quality of early players not well suited for music; some early models had an unreliable mechanical design. In 1971, the Advent Corporation introduced their Model 201 tape deck that combined Dolby type B noise reduction and chromium oxide tape, with a commercial-grade tape transport mechanism supplied by the Wollensak camera division of 3M Corporation; this resulted in the format being taken more for musical use, started the era of high fidelity cassettes and players. Although the birth and growth of the cassette began in the 1960s, its cultural moment took place during the 1970s and 1980s; the cassette's popularity grew
EIAJ-1
EIAJ-1 was a standard for video tape recorders developed by the Electronic Industries Association of Japan with the cooperation and assistance of several Japanese electronics manufacturers in 1969. It was the first standardized format for industrial/non-broadcast VTRs using a Helical scan system employing open reel tape; each manufacturer of machines in this market used a different proprietary format, with differing tape speeds, scanner drum diameters, bias frequencies, tracking head placement, so on, although most used 1/2" wide tape. As a result, video tapes recorded on one make and/or model of VTR could only be interchanged with other machines using that specific format, hampering compatibility. For example, a reel of tape recorded on a Panasonic machine would not play on a Sony machine, vice versa; the EIAJ-1 standard ended this incompatibility, giving those manufacturers a standardized format, interchangeable with all VTRs subsequently brought to market around that time. The format offered black-and-white video recording and playback on 1/2" magnetic tape on a 7" diameter open reel, with portable units using smaller 5" diameter reels.
The EIAJ-1 standard paved the way for consumer oriented non-professional analog video recording technology to become more affordable and widespread, with many businesses, government agencies and some consumers adopting the format in the early 1970s. Some of the first public-access television cable stations that started up around that time used EIAJ-1 equipment extensively, due to its portability, low cost, versatility; the original Sony Portapak, model CV-2000, used a proprietary format, but was superseded by an EIAJ-1 compatible version, the AV-3400. When EIAJ-1 was standardized, no videocassette recorders had yet been introduced. One of the main drawbacks to the format was the need to thread the end of the tape around the head drum, through a gap between the capstan and pinch roller, around a variety of guides and tensioners. If the user made any errors in doing this, the machine would malfunction and the tape could become damaged. So, another version, EIAJ-2, was released on that used a single-reel cartridge instead of an open take up reel.
Otherwise, the recording specifications were the same. By 1971, Sony introduced the U-matic format; the U-Matic system offered many advantages over EIAJ-1, including color recording as standard, stereo sound, automatic tape threading. However, EIAJ-1 equipment remained popular for a number of years as it was less expensive than U-Matic machines or tape, EIAJ-1 equipment was lighter and more compact, portable battery operated EIAJ-1 machines with companion video cameras were available, it wasn't until the mid 1970s that portable U-Matic machines and compatible portable color cameras were introduced. Neither the EIAJ-1 nor the U-Matic format were used in a Camcorder camera recorder unit, because of the size and weight of the mechanism involved; the recorder and camera were always separate units, connected by a multi conductor cable. The advent of the camcorder did not occur until the introduction of smaller, lighter cassette formats, such as Betamax and VHS. Information & specifications on EIAJ-1 DC Video 1/2 VTR page Video interchange change video history on EIAJ 1/2" Half Inch Open Reel Video Tape Information & specifications on Sony EIAJ-1 Experimental Television Center - Panasonic 1/2" specs Experimental Television Center - Sony AV-3400 Portapak Sony CV Series Video information
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