Nokia Bell Labs is an industrial research and scientific development company owned by Finnish company Nokia. Its headquarters are located in New Jersey. Other laboratories are located around the world. Bell Labs has its origins in the complex past of the Bell System. In the late 19th century, the laboratory began as the Western Electric Engineering Department and was located at 463 West Street in New York City. In 1925, after years of conducting research and development under Western Electric, the Engineering Department was reformed into Bell Telephone Laboratories and under the shared ownership of American Telephone & Telegraph Company and Western Electric. Researchers working at Bell Labs are credited with the development of radio astronomy, the transistor, the laser, the photovoltaic cell, the charge-coupled device, information theory, the Unix operating system, the programming languages C, C++, S. Nine Nobel Prizes have been awarded for work completed at Bell Laboratories. In 1880, when the French government awarded Alexander Graham Bell the Volta Prize of 50,000 francs (approximately US$10,000 at that time for the invention of the telephone, he used the award to fund the Volta Laboratory in Washington, D.
C. in collaboration with Sumner Tainter and Bell's cousin Chichester Bell. The laboratory was variously known as the Volta Bureau, the Bell Carriage House, the Bell Laboratory and the Volta Laboratory, it focused on the analysis and transmission of sound. Bell used his considerable profits from the laboratory for further research and education to permit the " diffusion of knowledge relating to the deaf": resulting in the founding of the Volta Bureau, located at Bell's father's house at 1527 35th Street N. W. in Washington, D. C, its carriage house became their headquarters in 1889. In 1893, Bell constructed a new building close by at 1537 35th Street N. W. to house the lab. This building was declared a National Historic Landmark in 1972. After the invention of the telephone, Bell maintained a distant role with the Bell System as a whole, but continued to pursue his own personal research interests; the Bell Patent Association was formed by Alexander Graham Bell, Thomas Sanders, Gardiner Hubbard when filing the first patents for the telephone in 1876.
Bell Telephone Company, the first telephone company, was formed a year later. It became a part of the American Bell Telephone Company. American Telephone & Telegraph Company and its own subsidiary company, took control of American Bell and the Bell System by 1889. American Bell held a controlling interest in Western Electric whereas AT&T was doing research into the service providers. In 1884, the American Bell Telephone Company created the Mechanical Department from the Electrical and Patent Department formed a year earlier. In 1896, Western Electric bought property at 463 West Street to station their manufacturers and engineers, supplying AT&T with their product; this included everything from telephones, telephone exchange switches, transmission equipment. In 1925, Bell Laboratories was developed to better consolidate the research activities of the Bell System. Ownership was evenly split between Western Electric and AT&T. Throughout the next decade the AT&T Research and Development branch moved into West Street.
Bell Labs carried out consulting work for the Bell Telephone Company, U. S. government work, a few workers were assigned to basic research. The first president of research at Bell Labs was Frank B. Jewett who stayed there until 1940. By the early 1940s, Bell Labs engineers and scientists had begun to move to other locations away from the congestion and environmental distractions of New York City, in 1967 Bell Laboratories headquarters was relocated to Murray Hill, New Jersey. Among the Bell Laboratories locations in New Jersey were Holmdel, Crawford Hill, the Deal Test Site, Lincroft, Long Branch, Neptune, Piscataway, Red Bank and Whippany. Of these, Murray Hill and Crawford Hill remain in existence; the largest grouping of people in the company was in Illinois, at Naperville-Lisle, in the Chicago area, which had the largest concentration of employees prior to 2001. There were groups of employees in Indianapolis, Indiana. Since 2001, many of the former locations closed; the Holmdel site, a 1.9 million square foot structure set on 473 acres, was closed in 2007.
The mirrored-glass building was designed by Eero Saarinen. In August 2013, Somerset Development bought the building, intending to redevelop it into a mixed commercial and residential project. A 2012 article expressed doubt on the success of the newly named Bell Works site however several large tenants had announced plans to move in through 2016 and 2017 Bell Laboratories was, is, regarded by many as the premier research facility of its type, developing a wide range of revolutionary technologies, including radio astronomy, the transistor, the laser, information theory, the operating system Unix, the programming languages C and C++, solar cells, the CCD, floating-gate MOSFET, a whole host of optical and wired communications
Betacam is a family of half-inch professional videocassette products developed by Sony in 1982. In colloquial use, "Betacam" singly is used to refer to a Betacam camcorder, a Betacam tape, a Betacam video recorder or the format itself. All Betacam variants from analog recording Betacam to Betacam SP and digital recording Digital Betacam, use the same shape videocassettes, meaning vaults and other storage facilities do not have to be changed when upgrading to a new format; the cassettes are available in two sizes: S and L. The Betacam camcorder can only load S magnetic tapes, while television studio sized video tape recorders designed for video editing can play both S and L tapes; the cassette shell and case for each Betacam cassette is colored differently depending on the format, allowing for easy visual identification. There is a mechanical key that allows a video tape recorder to identify which format has been inserted; the smaller S cassettes use the same form factor as Betamax. The format supplanted the three-quarter-inch U-Matic format, which Sony had introduced in 1971.
In addition to improvements in video quality, the Betacam configuration of an integrated professional video camera/recorder led to its rapid adoption by electronic news gathering organizations. DigiBeta, the common name for Digital Betacam, went on to become the single most successful professional broadcast digital recording video tape format in history. Though Betacam remains popular in the field and for archiving, new tapeless digital products such as the Multi Access Video Disk Recorder are leading to a phasing out of Betacam products in a television studio environment, as of 2006; the original Betacam format was launched on August 7, 1982. It is an analog component video format, storing the luminance, "Y", in one track and the chrominance, on another as alternating segments of the R-Y and B-Y components performing Compressed Time Division Multiplex, or CTDM; this splitting of channels allows true broadcast quality recording with 300 lines of horizontal luminance resolution and 120 lines chrominance resolution, on a inexpensive cassette based format.
The original Betacam format records on cassettes loaded with ferric oxide–formulated tape, which are theoretically the same as used by its consumer market-oriented predecessor Betamax, introduced seven years earlier by Sony in 1975. A blank Betamax-branded tape will work on a Betacam deck, a Betacam-branded tape can be used to record in a Betamax deck. However, in years Sony discouraged this practice, suggesting that the internal tape transport of a domestic Betamax cassette was not well suited to the faster tape transport of Betacam. In particular, the guide rollers tend to be noisy. Although there is a superficial similarity between Betamax and Betacam in that they use the same tape cassette, they are quite different formats. Betamax records low resolution video using a heterodyne color recording system and only two recording heads, while Betacam uses four heads to record in component format, at a much higher linear tape speed of 10.15 cm/s compared with Betamax's 1.87 cm/s, resulting in much higher video and audio quality.
A typical L-750 length Betamax cassette that yielded about 3 hours of recording time on a Betamax VCR at its B-II Speed, or on PAL, only provided 30 minutes' record time on a Betacam VCR or camcorder. Another common point between Betamax and Betacam is the placement of the stereo linear audio tracks; some Betacam and Betamax portables share the same batteries.. Betacam was introduced as a camera line along with a video cassette player; the first cameras were the BVP-3, which utilized three saticon tubes, the BVP1, which used a single tri-stripe Trinicon tube. Both these cameras could be operated standalone, or with their docking companion VTR, the BVV-1, to form the BVW-1 integrated camcorder; those decks were record-only. The only transport controls on the deck were Rewind; the docked camera's VTR button paused the tape recorder. The Betacam SP docking decks had full transport controls but tapes could not be played back except in the camera's viewfinder in black-and-white only. Sony came out with the Play Adapter, a separate portable unit that connected via a multi-pin cable and had a composite video out jack for color playback.
At first color playback required the studio source deck, the BVW-10, which could not record, only play back. It was designed as a feeder deck for A/B roll edit systems for editing to a one-inch Type C or three-quarter-inch U-matic cassette edit master tape. There was the BVW-20 field playback deck, a portable unit with DC power and a handle, used to verify color playback of tapes in the field. Unlike the BVW-10, it did not have a built in Time Base Corrector, or TBC. With the popular success of the Betacam system as a news acquisition format, the line was soon extended to include the BVW-15 studio player, the BVW-40 Studio Edit Recorder; the BVW-15 added Dynamic Tracking, which enabled clear still frame and jog playback, something the BVW-10 could not deliver. The BVW-40 enabled for the first time editing to a Betacam master, if set up and wired true component video editing, it was possible to do machine to machine editing between a BVW-10/15 and BVW-40 without an edit controller—a single seri
A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals; because the controlled power can be higher than the controlling power, a transistor can amplify a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits; the transistor is the fundamental building block of modern electronic devices, is ubiquitous in modern electronic systems. Julius Edgar Lilienfeld patented a field-effect transistor in 1926 but it was not possible to construct a working device at that time; the first implemented device was a point-contact transistor invented in 1947 by American physicists John Bardeen, Walter Brattain, William Shockley. The transistor revolutionized the field of electronics, paved the way for smaller and cheaper radios and computers, among other things.
The transistor is on the list of IEEE milestones in electronics, Bardeen and Shockley shared the 1956 Nobel Prize in Physics for their achievement. Most transistors are made from pure silicon or germanium, but certain other semiconductor materials can be used. A transistor may have only one kind of charge carrier, in a field effect transistor, or may have two kinds of charge carriers in bipolar junction transistor devices. Compared with the vacuum tube, transistors are smaller, require less power to operate. Certain vacuum tubes have advantages over transistors at high operating frequencies or high operating voltages. Many types of transistors are made to standardized specifications by multiple manufacturers; the thermionic triode, a vacuum tube invented in 1907, enabled amplified radio technology and long-distance telephony. The triode, was a fragile device that consumed a substantial amount of power. In 1909 physicist William Eccles discovered the crystal diode oscillator. Physicist Julius Edgar Lilienfeld filed a patent for a field-effect transistor in Canada in 1925, intended to be a solid-state replacement for the triode.
Lilienfeld filed identical patents in the United States in 1926 and 1928. However, Lilienfeld did not publish any research articles about his devices nor did his patents cite any specific examples of a working prototype; because the production of high-quality semiconductor materials was still decades away, Lilienfeld's solid-state amplifier ideas would not have found practical use in the 1920s and 1930s if such a device had been built. In 1934, German inventor Oskar Heil patented a similar device in Europe. From November 17, 1947, to December 23, 1947, John Bardeen and Walter Brattain at AT&T's Bell Labs in Murray Hill, New Jersey of the United States performed experiments and observed that when two gold point contacts were applied to a crystal of germanium, a signal was produced with the output power greater than the input. Solid State Physics Group leader William Shockley saw the potential in this, over the next few months worked to expand the knowledge of semiconductors; the term transistor was coined by John R. Pierce as a contraction of the term transresistance.
According to Lillian Hoddeson and Vicki Daitch, authors of a biography of John Bardeen, Shockley had proposed that Bell Labs' first patent for a transistor should be based on the field-effect and that he be named as the inventor. Having unearthed Lilienfeld’s patents that went into obscurity years earlier, lawyers at Bell Labs advised against Shockley's proposal because the idea of a field-effect transistor that used an electric field as a "grid" was not new. Instead, what Bardeen and Shockley invented in 1947 was the first point-contact transistor. In acknowledgement of this accomplishment, Shockley and Brattain were jointly awarded the 1956 Nobel Prize in Physics "for their researches on semiconductors and their discovery of the transistor effect". In 1948, the point-contact transistor was independently invented by German physicists Herbert Mataré and Heinrich Welker while working at the Compagnie des Freins et Signaux, a Westinghouse subsidiary located in Paris. Mataré had previous experience in developing crystal rectifiers from silicon and germanium in the German radar effort during World War II.
Using this knowledge, he began researching the phenomenon of "interference" in 1947. By June 1948, witnessing currents flowing through point-contacts, Mataré produced consistent results using samples of germanium produced by Welker, similar to what Bardeen and Brattain had accomplished earlier in December 1947. Realizing that Bell Labs' scientists had invented the transistor before them, the company rushed to get its "transistron" into production for amplified use in France's telephone network; the first bipolar junction transistors were invented by Bell Labs' William Shockley, which applied for patent on June 26, 1948. On April 12, 1950, Bell Labs chemists Gordon Teal and Morgan Sparks had produced a working bipolar NPN junction amplifying germanium transistor. Bell Labs had announced the discovery of this new "sandwich" transistor in a press release on July 4, 1951; the first high-frequency transistor was the surface-barrier germanium transistor developed by Philco in 1953, capable of operating up to 60 MHz.
These were made by etching depressions into an N-type germanium base from both sides with jets of Indium sulfate until it was a few ten-thousandths of an inch thick. Indium electroplated into the depressions formed the emitter; the first "prototype" pocket transistor radio was shown by I
Handycam is a Sony brand used to market its camcorder range. It was launched in 1985 as the name of the first Video8 camcorder, replacing Sony's previous line of Betamax-based models, the name was intended to emphasize the "handy" palm size nature of the camera, made possible by the new miniaturized tape format; this was in marked contrast to the larger, shoulder mounted cameras available before the creation of Video8, competing smaller formats such as VHS-C. Sony has continued to produce Handycams in a variety of guises since, developing the Video8 format to produce Hi8 and Digital8, using the same basic format to record digital video; the Handycam label continues to be applied. Select flagship Sony HandyCam models feature infrared night-vision, dubbed NightShot which utilizes an infrared light-emitting diode and an infrared filter, mechanically attached, detached to the sensor in order to enable the camcorder to record video footage in complete darkness; the NightShot feature is popular among a multitude of paranormal investigators, Travel Channel's Ghost Adventures.
Video8 Handycam Hi8 Handycam Digital8 Handycam DV Handycam HDV Handycam DVD-Handycam HDD Handycam Memory Stick Handycam Sony Handycam NEX-VG10 AVCHD Camcorder List of Sony trademarks Handycam website of Sony Middle East and Africa Handycam Camcorder page of Sony Singapore http://www.sony-asia.com/microsite/handycam/
Sony α, is a camera system introduced on 5 June 2006. It uses and expands upon Konica Minolta camera technologies, including the Minolta AF SLR lens mount, whose assets were acquired by Sony after the end of Konica Minolta's photography operations in early 2006. Sony has an 11.08% ownership stake in Japanese lens manufacturer Tamron, known to have partnered with Konica Minolta and Sony in the design and manufacture of many zoom lenses. Prior to the acquisition by Sony, the α branding had been used on the Japanese market by Minolta for their AF camera system. Sony adopted the name "A-mount system" for the Minolta AF lens mount, retained in their new SLR range. Sony's entry into the DSLR market dates back to July 2005 where a joint venture with Konica Minolta would have resulted in both companies marketing an updated line of DSLRs to the masses. Between 2006 and 2008 Sony was the fastest growing company on the DSLR market, reaching 13% market share in 2008 to become the third largest DSLR company in the world.
In May 2010, Sony introduced two α NEX mirrorless interchangeable lens cameras equipped with the new proprietary Sony E-mount. A-mount lenses can be used in E-mount cameras with an adapter - four different adapters are available from Sony alone. Sony announced plans to introduce a special camera service programme for professional photographers since the launch of the α900 in 2008. Sony Imaging PRO Support was established starting between 2013 and 2015 depending on country; the Sony α model system works on the principle that the next model up in the series has additional features to the one below. Only a few Sony APS-C DSLRs have Live View, except for the Sony α100, α200, α230, α290, α700, α850 and α900 series. Live View mode features a 1.4x or 2x Smart Teleconverter which digitally zooms in on the subject and reproduces pixels on a 1:1 basis, preventing degradation of picture quality. In 2010 Sony replaced the legacy DSLR design with SLT cameras, where the "SLT" stands for "single-lens translucent" which refers to a fixed beam splitter in the image path.
Sony SLT can shoot movie files at Full HD 1080p AVCHD with continuous phase detection autofocus. Along with the α33 and α55 cameras, Sony announced one of the last Sony DSLRs - the α560 which can shoot movie files at full HD stereo 1080p AVCHD, but with limited manual controls and no continuous AF; these three cameras use. The α33 and α55 are SLT based and can take movie files with continuous Auto Focus, whereas DSLRs using reflex mirrors cannot, at least not without limitations; the A-mount known as the A-type bayonet mount was introduced by Minolta in 1985 as the world's first integrated SLR autofocus system. As a result, all Minolta A-mount lenses can be used on Sony DSLRs, all Sony A-mount lenses work on Minolta's film and digital SLRs. During the initial introduction of the α system in 2006, Sony announced 19 lenses and 2 tele-converters, of which the majority were rebranded Konica Minolta lenses. At the 2007 PMA trade show, Sony unveiled several new lenses, but referred to them only in qualitative terms and did not provide specifications.
On 18 May 2009, Sony introduced the first A-mount lenses to feature their new SAM in-lens auto-focus motor for more lens-specific AF speed improvements. This introduction was made with the new "+30" series camera bodies; these new bodies retain an in-body focus motor for backward compatibility with the historic lens collection. In addition, the new bodies utilize HDMI output for display on HDTV sets and feature dual memory card slots for both Sony's proprietary Memory Stick Pro Duo chips as well as SDHC media format, while eliminating CompactFlash support. In 2010 Sony added the E-mount system to their Sony α lineup; this includes mirrorless cameras as well as camcorders. First they were all called "NEX" but this name has been dropped for "ILCE" for the mirrorless stills cameras; the 4-pin Auto-lock Accessory Shoe on all Sony DSLRs/SLTs and some NEX models up to 2012-08 was introduced by Minolta in 1988 for their Maxxum/Dynax/α series of A-mount AF SLRs and was used on their digital DiMAGE A cameras series.
It offers a slide-on auto-locking mechanism but is mechanically incompatible with hotshoes based on the ISO 518 standard as utilized by most other camera and accessory manufacturers. A compatible 7-pin variant existed as well, but was used by Minolta, not at all by Sony; the passive adapters Minolta FS-1100 and FS-PC allow to adapt Minolta AF and TTL flashes with ISO-based foot to cameras with Auto-lock Accessory Shoe, whereas the FS-1200 allows users to use AF TTL flashes with Auto-lock Accessory Foot on earlier Minolta SLRs. These adapters provide no voltage protection or galvanic isolation, but they maintain TTL support with Minolta film cameras. Digital cameras, require digital-ready flashes for TTL support. If no TTL support, but voltage protection and galvanic isolation is required, the Sony FA-HS1AM can be used instead to mount ISO-based equipment on Auto-lock Accessory Shoe cameras. If no electrical connection is re
A transistor radio is a small portable radio receiver that uses transistor-based circuitry. Following their development in 1954, made possible by the invention of the transistor in 1947, they became the most popular electronic communication device in history, with billions manufactured during the 1960s and 1970s, their pocket size sparked a change in popular music listening habits, allowing people to listen to music anywhere they went. Beginning in the 1980s, cheap AM transistor radios were superseded by devices with higher audio quality such as portable CD players, personal audio players and smartphones, some of which contain radios themselves. Before the transistor was invented, radios used vacuum tubes. Although portable vacuum tube radios were produced, they were bulky and heavy; the need for a low voltage high current source to power the filaments of the tubes and high voltage for the anode potential required two batteries. Vacuum tubes were inefficient and fragile compared to transistors, had a limited lifetime.
Bell Laboratories demonstrated the first transistor on December 23, 1947. The scientific team at Bell Laboratories responsible for the solid-state amplifier included William Shockley, Walter Houser Brattain, John Bardeen. After obtaining patent protection, the company held a news conference on June 30, 1948, at which a prototype transistor radio was demonstrated. There are many claimants to the title of the first company to produce practical transistor radios incorrectly attributed to Sony. Texas Instruments had demonstrated all-transistor AM radios as early as May 25, 1954, but their performance was well below that of equivalent vacuum tube models. A workable all-transistor radio was demonstrated in August 1953 at the Düsseldorf Radio Fair by the German firm Intermetall, it was built with four of Intermetall's hand-made transistors, based upon the 1948 invention of the "Transistron"-germanium point-contact transistor by Herbert Mataré and Heinrich Welker. However, as with the early Texas Instruments units only prototypes were built.
RCA had demonstrated a prototype transistor radio as early as 1952, it is that they and the other radio makers were planning transistor radios of their own, but Texas Instruments and Regency Division of I. D. E. A. Were the first to offer a production model starting in October 1954; the use of transistors instead of vacuum tubes as the amplifier elements meant that the device was much smaller, required far less power to operate than a tube radio, was more shock-resistant. Since the transistor base draws current, its input impedance is low in contrast to the high input impedance of the vacuum tubes, it allowed "instant-on" operation, since there were no filaments to heat up. The typical portable tube radio of the fifties was about the size and weight of a lunchbox, contained several heavy, non-rechargeable batteries— one or more so-called "A" batteries to heat the tube filaments and a large 45- to 90-volt "B" battery to power the signal circuits. By comparison, the transistor radio could fit in a pocket and weighed half a pound or less, was powered by standard flashlight batteries or a single compact 9-volt battery.
The now-familiar 9-volt battery was introduced for powering transistor radios. Listeners sometimes held an entire transistor radio directly against the side of the head, with the speaker against the ear, to minimize the "tinny" sound caused by the high resonant frequency of its small speaker. Most radios included earphone jacks and came with single earphones that provided only mediocre-quality sound reproduction. To consumers familiar with the earphone-listening experience of the transistor radio, the first Sony Walkman cassette player, with a pair of high-fidelity stereo earphones, would provide a contrasting display of audio fidelity. Two companies working together, Texas Instruments of Dallas and Industrial Development Engineering Associates of Indianapolis, were behind the unveiling of the Regency TR-1, the world's first commercially produced transistor radio. Texas Instruments was producing instrumentation for the oil industry and locating devices for the U. S. Navy and I. D. E. A. Built home television antenna boosters.
The two companies worked together on the TR-1, looking to grow revenues for their respective companies by breaking into this new product area. In May 1954, Texas Instruments had designed and built a prototype and was looking for an established radio manufacturer to develop and market a radio using their transistors. None of the major radio makers including RCA, Emerson were interested; the President of I. D. E. A. at the time, Ed Tudor, jumped at the opportunity to manufacture the TR-1, predicting sales of the transistor radios at "20 million radios in three years". The Regency TR-1 was announced on October 18, 1954 by the Regency Division of I. D. E. A. was put on sale in November 1954, was the first practical transistor radio made in any significant numbers. Billboard reported in 1954. One acts as a combination mixer-oscillator, one as an audio amplifier, two as intermediate-frequency amplifiers." One year after the release of the TR-1 sales approached the 100,000 mark. The look and size of the TR-1 was well received, but the reviews of the TR-1's performance were ad
DV is a format for storing digital video. It was launched in 1995 with joint efforts of leading producers of video camera recorders; the original DV specification, known as Blue Book, was standardized within the IEC 61834 family of standards. These standards define common features such as physical videocassettes, recording modulation method and basic system data in part 1. Part 2 describes the specifics of 625-50 systems; the IEC standards are available as publications sold by IEC and ANSI. In 2003, DV was joined by a successor format HDV, which used the same tape format with a different video codec; some cameras at the time had the ability to switch between HDV recording modes. All tape-based video formats are becoming obsolete as tapeless HD cameras recording on memory cards, hard disk drives, solid-state drives, optical discs have become the norm, although the DV encoding standard is sometimes still used in tapeless cameras. DV uses lossy compression of video. An intraframe video compression scheme is used to compress video on a frame-by-frame basis with the discrete cosine transform.
Following ITU-R Rec. 601 standard, DV video employs interlaced scanning with the luminance sampling frequency of 13.5 MHz. These results in 480 scanlines per complete frame for the 60 Hz system, 576 scanlines per complete frame for the 50 Hz system. In both systems the active area contains 720 pixels per scanline, with 704 pixels used for content and 16 pixels on the sides left for digital blanking; the same frame size is used for 4:3 and 16:9 frame aspect ratios, resulting in different pixel aspect ratios for fullscreen and widescreen video. Prior to the DCT compression stage, chroma subsampling is applied to the source video in order to reduce the amount of data to be compressed. Baseline DV uses 4:2:0 subsampling in the 50 Hz variant. Low chroma resolution of DV is a reason this format is sometimes avoided in chroma keying applications, though advances in chroma keying techniques and software have made producing quality keys from DV material possible. Audio can be stored in either of two forms: 16-bit Linear PCM stereo at 48 kHz sampling rate, or four nonlinear 12-bit PCM channels at 32 kHz sampling rate.
In addition, the DV specification supports 16-bit audio at 44.1 kHz, the same sampling rate used for CD audio. In practice, the 48 kHz stereo mode is used exclusively; the audio and metadata are packaged into 80-byte Digital Interface Format blocks which are multiplexed into a 150-block sequence. DIF blocks are the basic units of DV streams and can be stored as computer files in raw form or wrapped in such file formats as Audio Video Interleave, QuickTime and Material Exchange Format. One video frame is formed from either 10 or 12 such sequences, depending on scanning rate, which results in a data rate of about 25 Mbit/s for video, an additional 1.5 Mbit/s for audio. When written to tape, each sequence corresponds to one complete track. Baseline DV employs unlocked audio; this means. However, this is the maximum drift of the audio/video synchronization. Sony and Panasonic created their proprietary versions of DV aimed toward professional & broadcast users, which use the same compression scheme, but improve on robustness, linear editing capabilities, color rendition and raster size.
All DV variants. Film-like frame rates are possible by using pulldown. DVCPRO HD supports native progressive format. DVCPRO known as DVCPRO25, is a variation of DV developed by Panasonic and introduced in 1995 for use in electronic news gathering equipment. Unlike baseline DV, DVCPRO uses locked audio and 4:1:1 chroma subsampling for both 50 Hz and 60 Hz variants to decrease generation losses. Audio is available in 16-bit/48 kHz precision; when recorded to tape, DVCPRO uses wider track pitch - 18 μm vs. 10 μm of baseline DV, which reduces the chance of dropout errors during recording. Two extra longitudinal tracks provide support for timecode control. Tape is transported 80% faster compared to baseline DV, resulting in shorter recording time. Long Play mode is not available. In 1996 Sony responded with its own professional version of DV called DVCAM. Like DVCPRO, DVCAM uses locked audio, which prevents audio synchronization drift that may happen on DV if several generations of copies are made; when recorded to tape, DVCAM uses 15 μm track pitch, 50% wider compared to baseline.
Accordingly, tape is transported 50% faster, which reduces recording time by one third compared to regular DV. Because of the wider track and track pitch, DVCAM has the ability to do a frame-accurate insert edit, while regular DV may vary by a few frames on each edit compared to the preview. DVCPRO50 was introduced by Panasonic in 1997 for high-value electronic news gathering and digital cinema, is described as two DV codecs working in parallel; the DVCPRO50 doubles the coded video data rate to 50 Mbit/s. This has the effect of cutting total record time of any given storage medium in half. Chroma resolution is improved by using 4:2:2 chroma subsampling. DVCPRO50 was used in many productions. For example, BBC used DVCPRO50 to record high-budget TV series, such as Space Race and Ancient Rome: The Rise and Fall of an Empire. A similar format, D-9, offered