1.
Sound recording and reproduction
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Sound recording and reproduction is an electrical, mechanical, electronic, or digital inscription and re-creation of sound waves, such as spoken voice, singing, instrumental music, or sound effects. The two main classes of sound recording technology are analog recording and digital recording, prior to the development of analog recording, there were mechanical systems for reproducing instrumental music, such as wind-up music boxes and later, in the late 19th century, player pianos. Analog sound reproduction is the process, with a bigger loudspeaker diaphragm causing changes to atmospheric pressure to form acoustic sound waves. Digital recording and reproduction converts the sound signal picked up by the microphone to a digital form by the process of digitization. This lets the audio data be stored and transmitted by a variety of media. Whereas successive copies of an analog recording tend to degrade in quality, as noise is added. A digital audio signal must be reconverted to analog form during playback before it is amplified and connected to a loudspeaker to produce sound, long before sound was first recorded on cylinders or records, music was recorded—first by written music notation, then also by mechanical devices. Fowler, this. cylinder with raised pins on the surface remained the device to produce and reproduce music mechanically until the second half of the nineteenth century. The Banu Musa brothers also invented an automatic flute player, which appears to have been the first programmable machine, according to Fowler, the automata were a robot band that performed. more than fifty facial and body actions during each musical selection. In the 14th century, Flanders introduced a mechanical bell-ringer controlled by a rotating cylinder, similar designs appeared in barrel organs, musical clocks, barrel pianos, and musical boxes. A music box is a musical instrument that produces sounds by the use of a set of pins placed on a revolving cylinder or disc so as to pluck the tuned teeth of a steel comb. They were developed from musical snuff boxes of the 18th century, some of the more complex boxes also have a tiny drum and/or bells, in addition to the metal comb. The fairground organ, developed in 1892, used a system of accordion-folded punched cardboard books, the player piano, first demonstrated in 1876, used a punched paper scroll that could store an long piece of music. The most sophisticated of the rolls were hand-played, meaning that the roll represented the actual performance of an individual. This technology to record a live performance onto a piano roll was not developed until 1904, piano rolls were in continuous mass production from 1896 to 2008. A1908 U. S. Supreme Court copyright case noted that, in 1902 alone, the use of piano rolls began to decline in the 1920s although one type is still being made today. The first device that could record actual sounds as they passed through the air was the phonautograph, the earliest known recordings of the human voice are phonautograph recordings, called phonautograms, made in 1857. They consist of sheets of paper with sound-wave-modulated white lines created by a stylus that cut through a coating of soot as the paper was passed under it
2.
Album
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Album, is a collection of audio recordings issued as a single item on CD, record, audio tape, or another medium. Albums of recorded music were developed in the early 20th century, first as books of individual 78rpm records, vinyl LPs are still issued, though in the 21st century album sales have mostly focused on compact disc and MP3 formats. The audio cassette was a format used from the late 1970s through to the 1990s alongside vinyl, an album may be recorded in a recording studio, in a concert venue, at home, in the field, or a mix of places. Recording may take a few hours to years to complete, usually in several takes with different parts recorded separately. Recordings that are done in one take without overdubbing are termed live, the majority of studio recordings contain an abundance of editing, sound effects, voice adjustments, etc. With modern recording technology, musicians can be recorded in separate rooms or at times while listening to the other parts using headphones. Album covers and liner notes are used, and sometimes additional information is provided, such as analysis of the recording, historically, the term album was applied to a collection of various items housed in a book format. In musical usage the word was used for collections of pieces of printed music from the early nineteenth century. Later, collections of related 78rpm records were bundled in book-like albums, the LP record, or 33 1⁄3 rpm microgroove vinyl record, is a gramophone record format introduced by Columbia Records in 1948. It was adopted by the industry as a standard format for the album. Apart from relatively minor refinements and the important later addition of stereophonic sound capability, the term album had been carried forward from the early nineteenth century when it had been used for collections of short pieces of music. Later, collections of related 78rpm records were bundled in book-like albums, as part of a trend of shifting sales in the music industry, some commenters have declared that the early 21st century experienced the death of the album. Sometimes shorter albums are referred to as mini-albums or EPs, Albums such as Tubular Bells, Amarok, Hergest Ridge by Mike Oldfield, and Yess Close to the Edge, include fewer than four tracks. There are no rules against artists such as Pinhead Gunpowder referring to their own releases under thirty minutes as albums. These are known as box sets, material is stored on an album in sections termed tracks, normally 11 or 12 tracks. A music track is a song or instrumental recording. The term is associated with popular music where separate tracks are known as album tracks. When vinyl records were the medium for audio recordings a track could be identified visually from the grooves
3.
LP record
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The LP is an analog sound storage medium, a vinyl record format characterized by a speed of 33 1⁄3 rpm, a 12 or 10 inch diameter, and use of the microgroove groove specification. Introduced by Columbia in 1948, it was adopted as a new standard by the entire record industry. Apart from a few relatively minor refinements and the important later addition of stereophonic sound, the new product was a 12- or 10-inch fine-grooved disc made of vinyl and played with a smaller-tipped microgroove stylus at a speed of 33 1⁄3 rpm. Each side of a 12-inch LP could play for more than 20 minutes, although the LP was suited to classical music because of its extended continuous playing time, it also allowed a collection of ten or more pop music recordings to be put on a single disc. The use of the word album persisted for the one-disc LP equivalent, the prototype of the LP was the soundtrack disc used by the Vitaphone motion picture sound system, developed by Western Electric and introduced in 1926. For soundtrack purposes, the less than five minutes of playing time of side of a conventional 12-inch 78 rpm disc was not acceptable. The sound had to play continuously for at least 11 minutes, long enough to accompany a full 1, the disc diameter was increased to 16 inches and the speed was reduced to 33 1⁄3 revolutions per minute. Unlike their smaller LP descendants, they were made with the same large standard groove used by 78s, unlike conventional records, the groove started at the inside of the recorded area near the label and proceeded outward toward the edge. Like 78s, early soundtrack discs were pressed in an abrasive shellac compound, syndicated radio programming was distributed on 78 rpm discs beginning in 1928. The desirability of a longer continuous playing time soon led to the adoption of the Vitaphone soundtrack disc format, 16-inch 33 1⁄3 rpm discs playing about 15 minutes per side were used for most of these electrical transcriptions beginning about 1930. Transcriptions were variously recorded inside out like soundtrack discs or with an outside start, some transcriptions were recorded with a vertically modulated hill and dale groove. This was found to allow deeper bass and also an extension of the frequency response. Neither of these was necessarily an advantage in practice because of the limitations of AM broadcasting. Today we can enjoy the benefits of those higher-fidelity recordings, even if the radio audiences could not. Initially, transcription discs were pressed only in shellac, but by 1932 pressings in RCA Victors vinyl-based Victrolac were appearing, by the late 1930s, vinyl was standard for nearly all kinds of pressed discs except ordinary commercial 78s, which continued to be made of shellac. Use of the LPs microgroove standard began in the late 1950s, the King Biscuit Flower Hour is a late example, as are Westwood Ones The Beatle Years and Doctor Demento programs, which were sent to stations on LP at least through 1992. RCA Victor introduced a version of a long-playing record for home use in September 1931. These Program Transcription discs, as Victor called them, played at 33 1⁄3 rpm and used a somewhat finer and they were to be played with a special Chromium Orange chrome-plated steel needle
4.
Compact disc
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Compact disc is a digital optical disc data storage format released in 1982 and co-developed by Philips and Sony. The format was developed to store and play only sound recordings but was later adapted for storage of data. The first commercially available Audio CD player, the Sony CDP-101, was released October 1982 in Japan, standard CDs have a diameter of 120 millimetres and can hold up to about 80 minutes of uncompressed audio or about 700 MiB of data. The Mini CD has various diameters ranging from 60 to 80 millimetres, they are used for CD singles, storing up to 24 minutes of audio. At the time of the introduction in 1982, a CD could store much more data than a personal computer hard drive. By 2010, hard drives commonly offered as much space as a thousand CDs. In 2004, worldwide sales of audio CDs, CD-ROMs and CD-Rs reached about 30 billion discs, by 2007,200 billion CDs had been sold worldwide. In 2014, revenues from digital music services matched those from physical format sales for the first time. American inventor James T. Russell has been credited with inventing the first system to record information on an optical transparent foil that is lit from behind by a high-power halogen lamp. Russells patent application was first filed in 1966, and he was granted a patent in 1970, following litigation, Sony and Philips licensed Russells patents in the 1980s. The compact disc is an evolution of LaserDisc technology, where a laser beam is used that enables the high information density required for high-quality digital audio signals. Prototypes were developed by Philips and Sony independently in the late 1970s, although originally dismissed by Philips Research management as a trivial pursuit, the CD became the primary focus for Philips as the LaserDisc format struggled. In 1979, Sony and Philips set up a joint task force of engineers to design a new audio disc. After a year of experimentation and discussion, the Red Book CD-DA standard was published in 1980, after their commercial release in 1982, compact discs and their players were extremely popular. Despite costing up to $1,000, over 400,000 CD players were sold in the United States between 1983 and 1984, by 1988 CD sales in the United States surpassed those of vinyl LPs, and by 1992 CD sales surpassed those of prerecorded music cassette tapes. The success of the disc has been credited to the cooperation between Philips and Sony, who came together to agree upon and develop compatible hardware. The unified design of the disc allowed consumers to purchase any disc or player from any company. In 1974, L. However, due to the performance of the analog format
5.
United Kingdom
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The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom or Britain, is a sovereign country in western Europe. Lying off the north-western coast of the European mainland, the United Kingdom includes the island of Great Britain, Northern Ireland is the only part of the United Kingdom that shares a land border with another sovereign state—the Republic of Ireland. The Irish Sea lies between Great Britain and Ireland, with an area of 242,500 square kilometres, the United Kingdom is the 78th-largest sovereign state in the world and the 11th-largest in Europe. It is also the 21st-most populous country, with an estimated 65.1 million inhabitants, together, this makes it the fourth-most densely populated country in the European Union. The United Kingdom is a monarchy with a parliamentary system of governance. The monarch is Queen Elizabeth II, who has reigned since 6 February 1952, other major urban areas in the United Kingdom include the regions of Birmingham, Leeds, Glasgow, Liverpool and Manchester. The United Kingdom consists of four countries—England, Scotland, Wales, the last three have devolved administrations, each with varying powers, based in their capitals, Edinburgh, Cardiff and Belfast, respectively. The relationships among the countries of the UK have changed over time, Wales was annexed by the Kingdom of England under the Laws in Wales Acts 1535 and 1542. A treaty between England and Scotland resulted in 1707 in a unified Kingdom of Great Britain, which merged in 1801 with the Kingdom of Ireland to form the United Kingdom of Great Britain and Ireland. Five-sixths of Ireland seceded from the UK in 1922, leaving the present formulation of the United Kingdom of Great Britain, there are fourteen British Overseas Territories. These are the remnants of the British Empire which, at its height in the 1920s, British influence can be observed in the language, culture and legal systems of many of its former colonies. The United Kingdom is a country and has the worlds fifth-largest economy by nominal GDP. The UK is considered to have an economy and is categorised as very high in the Human Development Index. It was the worlds first industrialised country and the worlds foremost power during the 19th, the UK remains a great power with considerable economic, cultural, military, scientific and political influence internationally. It is a nuclear weapons state and its military expenditure ranks fourth or fifth in the world. The UK has been a permanent member of the United Nations Security Council since its first session in 1946 and it has been a leading member state of the EU and its predecessor, the European Economic Community, since 1973. However, on 23 June 2016, a referendum on the UKs membership of the EU resulted in a decision to leave. The Acts of Union 1800 united the Kingdom of Great Britain, Scotland, Wales and Northern Ireland have devolved self-government
6.
Columbia Records
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Columbia Records is an American record label owned by Sony Music Entertainment, a subsidiary of Sony Corporation of America, Inc. the United States division of Sony Corporation. It was founded in 1887, evolving from an enterprise named the American Graphophone Company. Columbia is the oldest surviving brand name in the sound business. Columbia Records went on to release records by an array of singers, instrumentalists. It is one of Sony Musics three flagship record labels alongside RCA Records and Epic Records, rather, as above, it was connected to CBS, a broadcasting media company which had purchased the company in 1938, and had been co-founded in 1927 by Columbia Records itself. Though Arista Records was sold to Bertelsmann Music Group, it would become a sister label of Columbia Records through its mutual connection to Sony Music. The Columbia Phonograph Company was founded in 1887 by stenographer, lawyer and New Jersey native Edward Easton and it derived its name from the District of Columbia, where it was headquartered. At first it had a monopoly on sales and service of Edison phonographs and phonograph cylinders in Washington. As was the custom of some of the regional companies, Columbia produced many commercial cylinder recordings of its own. Columbias ties to Edison and the North American Phonograph Company were severed in 1894 with the North American Phonograph Companys breakup, thereafter it sold only records and phonographs of its own manufacture. In 1902, Columbia introduced the XP record, a brown wax record. According to Gracyk, the molded brown waxes may have sold to Sears for distribution. Columbia began selling records and phonographs in addition to the cylinder system in 1901, preceded only by their Toy Graphophone of 1899. For a decade, Columbia competed with both the Edison Phonograph Company cylinders and the Victor Talking Machine Company disc records as one of the top three names in American recorded sound. In order to add prestige to its catalog of artists. The firm also introduced the internal-horn Grafonola to compete with the extremely popular Victrola sold by the rival Victor Talking Machine Company, during this era, Columbia used the famous Magic Notes logo—a pair of sixteenth notes in a circle—both in the United States and overseas. Columbia was split into two companies, one to make records and one to make players, Columbia Phonograph was moved to Connecticut, and Ed Easton went with it. Eventually it was renamed the Dictaphone Corporation, in late 1923, Columbia went into receivership
7.
RCA Records
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RCA Records is an American record label owned by Sony Music Entertainment, a subsidiary of Sony Corporation of America, Inc. It is one of SMEs three flagship labels, alongside Columbia Records and Epic Records. The label has released multiple genres of music, including pop, rock, hip hop, R&B, blues, jazz, the companys name is derived from the initials of the labels former parent company, the Radio Corporation of America. It is the second oldest recording company in US history, after sister label Columbia Records, RCAs Canadian unit is Sonys oldest label in Canada. It was one of only two Canadian record companies to survive the Great Depression, kelly, Enrique Iglesias, Foo Fighters, Kings of Leon, Kesha, Miley Cyrus, Giorgio Moroder, Jennifer Hudson, DAngelo, Pink, Tinashe, G-Eazy, Pitbull, Zayn and Wizkid. In 1929, the Radio Corporation of America purchased the Victor Talking Machine Company, then the worlds largest manufacturer of phonographs and phonograph records. The company then became RCA Victor but retained use of the Victor Records name on their labels until the beginning of 1946 when the labels were finally switched over to RCA Victor. With Victor, RCA acquired New World rights to the famous Nipper His Masters Voice trademark, in Shanghai, China, in 1931, RCA Victors British affiliate the Gramophone Company merged with the Columbia Graphophone Company to form EMI. This gave RCA head David Sarnoff a seat on the EMI board, in September 1931, RCA Victor introduced the first 33⅓ rpm records sold to the public, calling them Program Transcriptions. In the depths of the Great Depression, the format was a commercial failure, during the early part of the depression, RCA made a number of attempts to produce a successful cheap label to compete with the dime store labels. The first was the short-lived Timely Tunes label in 1931 sold at Montgomery Ward, in 1932, Bluebird Records was created as a sub-label of RCA Victor. It was originally an 8-inch record with a blue label. In 1933, RCA reintroduced Bluebird and Electradisk as a standard 10-inch label, another cheap label, Sunrise, was produced. The same musical couplings were issued on all three labels and Bluebird Records still survives eight decades after Electradisk and Sunrise were discontinued, RCA also produced records for Montgomery Ward label during the 1930s. Besides manufacturing records for themselves, RCA Victor operated RCA Custom which was the leading record manufacturer for independent record labels, RCA Custom also pressed record compilations for The Readers Digest Association. RCA sold its interest in EMI in 1935, but EMI continued to distribute RCA recordings in the UK, RCA also manufactured and distributed HMV classical recordings on the RCA and HMV labels in North America. During World War II, ties between RCA and its Japanese affiliate JVC were severed, the Japanese record company is today called Victor Entertainment and is still a JVC subsidiary. From 1942 to 1944, RCA Victor was seriously impacted by the American Federation of Musicians recording ban, virtually all union musicians could not make recordings during that period
8.
Phonograph
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The phonograph is a device invented in 1877 for the mechanical recording and reproduction of sound. In its later forms it is called a gramophone. To recreate the sound, the surface is rotated while a playback stylus traces the groove and is therefore vibrated by it. In later electric phonographs, the motions of the stylus are converted into an electrical signal by a transducer. The phonograph was invented in 1877 by Thomas Edison, while other inventors had produced devices that could record sounds, Edisons phonograph was the first to be able to reproduce the recorded sound. His phonograph originally recorded sound onto a sheet wrapped around a rotating cylinder. A stylus responding to sound vibrations produced an up and down or hill-and-dale groove in the foil, in the 1890s, Emile Berliner initiated the transition from phonograph cylinders to flat discs with a spiral groove running from the periphery to near the center. Later improvements through the years included modifications to the turntable and its system, the stylus or needle. The disc phonograph record was the dominant audio recording format throughout most of the 20th century, from the mid-1980s on, phonograph use on a standard record player declined sharply because of the rise of the cassette tape, compact disc and other digital recording formats. Records are still a favorite format for some audiophiles and DJs, vinyl records are still used by some DJs and musicians in their concert performances. Musicians continue to release their recordings on vinyl records, the original recordings of musicians are sometimes re-issued on vinyl. Usage of terminology is not uniform across the English-speaking world, in more modern usage, the playback device is often called a turntable, record player, or record changer. When used in conjunction with a mixer as part of a DJ setup, the term phonograph was derived from the Greek words φωνή and γραφή. The similar related terms gramophone and graphophone have similar root meanings, the roots were already familiar from existing 19th-century words such as photograph, telegraph, and telephone. In British English, gramophone may refer to any sound-reproducing machine using disc records, the term phonograph was usually restricted to machines that used cylinder records. Gramophone generally referred to a wind-up machine, after the introduction of the softer vinyl records, 33 1⁄3-rpm LPs and 45-rpm single or two-song records, and EPs, the common name became record player or turntable. Often the home record player was part of a system that included a radio and, later, from about 1960, such a system began to be described as a hi-fi or a stereo. In American English, phonograph, properly specific to machines made by Edison, was used in a generic sense as early as the 1890s to include cylinder-playing machines made by others
9.
Classical music
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Classical music is art music produced or rooted in the traditions of Western music, including both liturgical and secular music. The central norms of this tradition became codified between 1550 and 1900, which is known as the common-practice period, Western staff notation is used by composers to indicate to the performer the pitches, tempo, meter and rhythms for a piece of music. This can leave less room for such as improvisation and ad libitum ornamentation. The term classical music did not appear until the early 19th century, the earliest reference to classical music recorded by the Oxford English Dictionary is from about 1836. This score typically determines details of rhythm, pitch, and, the written quality of the music has enabled a high level of complexity within them, J. S. The use of written notation also preserves a record of the works, Musical notation enables 2000s-era performers to sing a choral work from the 1300s Renaissance era or a 1700s Baroque concerto with many of the features of the music being reproduced. That said, the score does not provide complete and exact instructions on how to perform a historical work, even if the tempo is written with an Italian instruction, we do not know exactly how fast the piece should be played. Bach was particularly noted for his complex improvisations, during the Classical era, the composer-performer Mozart was noted for his ability to improvise melodies in different styles. During the Classical era, some virtuoso soloists would improvise the cadenza sections of a concerto, during the Romantic era, Beethoven would improvise at the piano. The instruments currently used in most classical music were largely invented before the mid-19th century and they consist of the instruments found in an orchestra or in a concert band, together with several other solo instruments. The symphony orchestra is the most widely known medium for music and includes members of the string, woodwind, brass. The concert band consists of members of the woodwind, brass and it generally has a larger variety and number of woodwind and brass instruments than the orchestra but does not have a string section. However, many bands use a double bass. Many of the used to perform medieval music still exist. Medieval instruments included the flute, the recorder and plucked string instruments like the lute. As well, early versions of the organ, fiddle, Medieval instruments in Europe had most commonly been used singly, often self accompanied with a drone note, or occasionally in parts. From at least as early as the 13th century through the 15th century there was a division of instruments into haut, during the earlier medieval period, the vocal music from the liturgical genre, predominantly Gregorian chant, was monophonic, using a single, unaccompanied vocal melody line. Polyphonic vocal genres, which used multiple independent vocal melodies, began to develop during the medieval era, becoming prevalent by the later 13th
10.
Arturo Toscanini
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Arturo Toscanini was an Italian conductor. He was one of the most acclaimed musicians of the late 19th and of the 20th century, renowned for his intensity, his perfectionism, his ear for detail and sonority. He was at times the music director of La Scala in Milan, the Metropolitan Opera in New York. Toscanini was born in Parma, Emilia-Romagna, and won a scholarship to the music conservatory. Living conditions at the conservatory were harsh, for example, his diet consisted almost completely of fish. When he became successful, he never ate anything that came from the sea and he joined the orchestra of an opera company, with which he toured South America in 1886. Carlo Superti and Aristide Venturi tried unsuccessfully to finish the work, in desperation, the singers suggested the name of their assistant Chorus Master, who knew the whole opera from memory. The public was taken by surprise, at first by the youth and sheer aplomb of this unknown conductor, for the rest of that season, Toscanini conducted eighteen operas, all with absolute success. Thus began his career as a conductor, at age 19, upon returning to Italy, Toscanini set out on a dual path for some time. He continued to conduct, his first appearance in Italy being at the Teatro Carignano in Turin, on November 4,1886, in the world premiere of the revised version of Alfredo Catalanis Edmea. This was the beginning of Toscaninis lifelong friendship and championing of Catalani, however, he also returned to his chair in the cello section, and participated as cellist in the world premiere of Verdis Otello under the composers supervision. The composer was impressed when Toscanini consulted him personally about Verdis Te Deum. Verdi said that he had left it out for fear that certain interpreters would have exaggerated the marking, gradually, Toscaninis reputation as an operatic conductor of unusual authority and skill supplanted his cello career. In the following decade, he consolidated his career in Italy, entrusted with the premieres of Puccinis La bohème. In 1896, Toscanini conducted his first symphonic concert and he exhibited a considerable capacity for hard work, conducting 43 concerts in Turin in 1898. By 1898, Toscanini was Principal Conductor at La Scala, where he remained until 1908, returning as Music Director and he brought the La Scala Orchestra to the United States on a concert tour in 1920/21, during which he made his first recordings. Outside Europe, Toscanini conducted at the Metropolitan Opera in New York as well as the New York Philharmonic Orchestra and he toured Europe with the New York Philharmonic in 1930. At each performance, he and the orchestra were acclaimed by critics, Toscanini was the first non-German conductor to appear at Bayreuth, and the New York Philharmonic was the first non-German orchestra to play there
11.
Radio
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When radio waves strike an electrical conductor, the oscillating fields induce an alternating current in the conductor. The information in the waves can be extracted and transformed back into its original form, Radio systems need a transmitter to modulate some property of the energy produced to impress a signal on it, for example using amplitude modulation or angle modulation. Radio systems also need an antenna to convert electric currents into radio waves, an antenna can be used for both transmitting and receiving. The electrical resonance of tuned circuits in radios allow individual stations to be selected, the electromagnetic wave is intercepted by a tuned receiving antenna. Radio frequencies occupy the range from a 3 kHz to 300 GHz, a radio communication system sends signals by radio. The term radio is derived from the Latin word radius, meaning spoke of a wheel, beam of light, however, this invention would not be widely adopted. The switch to radio in place of wireless took place slowly and unevenly in the English-speaking world, the United States Navy would also play a role. Although its translation of the 1906 Berlin Convention used the terms wireless telegraph and wireless telegram, the term started to become preferred by the general public in the 1920s with the introduction of broadcasting. Radio systems used for communication have the following elements, with more than 100 years of development, each process is implemented by a wide range of methods, specialised for different communications purposes. Each system contains a transmitter, This consists of a source of electrical energy, the transmitter contains a system to modulate some property of the energy produced to impress a signal on it. This modulation might be as simple as turning the energy on and off, or altering more subtle such as amplitude, frequency, phase. Amplitude modulation of a carrier wave works by varying the strength of the signal in proportion to the information being sent. For example, changes in the strength can be used to reflect the sounds to be reproduced by a speaker. It was the used for the first audio radio transmissions. Frequency modulation varies the frequency of the carrier, the instantaneous frequency of the carrier is directly proportional to the instantaneous value of the input signal. FM has the capture effect whereby a receiver only receives the strongest signal, Digital data can be sent by shifting the carriers frequency among a set of discrete values, a technique known as frequency-shift keying. FM is commonly used at Very high frequency radio frequencies for high-fidelity broadcasts of music, analog TV sound is also broadcast using FM. Angle modulation alters the phase of the carrier wave to transmit a signal
12.
NBC
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The National Broadcasting Company is an American commercial broadcast television network that is the flagship property of NBCUniversal, a subsidiary of Comcast. The network is part of the Big Three television networks, founded in 1926 by the Radio Corporation of America, NBC is the oldest major broadcast network in the United States. Following the acquisition by GE, Bob Wright served as executive officer of NBC, remaining in that position until his retirement in 2007. In 2003, French media company Vivendi merged its entertainment assets with GE, Comcast purchased a controlling interest in the company in 2011, and acquired General Electrics remaining stake in 2013. Following the Comcast merger, Zucker left NBC Universal and was replaced as CEO by Comcast executive Steve Burke, during a period of early broadcast business consolidation, radio manufacturer Radio Corporation of America acquired New York City radio station WEAF from American Telephone & Telegraph. Westinghouse, a shareholder in RCA, had an outlet in Newark, New Jersey pioneer station WJZ. This station was transferred from Westinghouse to RCA in 1923, WEAF acted as a laboratory for AT&Ts manufacturing and supply outlet Western Electric, whose products included transmitters and antennas. The Bell System, AT&Ts telephone utility, was developing technologies to transmit voice- and music-grade audio over short and long distances, the 1922 creation of WEAF offered a research-and-development center for those activities. WEAF maintained a schedule of radio programs, including some of the first commercially sponsored programs. In an early example of chain or networking broadcasting, the station linked with Outlet Company-owned WJAR in Providence, Rhode Island, AT&T refused outside companies access to its high-quality phone lines. The early effort fared poorly, since the telegraph lines were susceptible to atmospheric. In 1925, AT&T decided that WEAF and its network were incompatible with the companys primary goal of providing a telephone service. AT&T offered to sell the station to RCA in a deal that included the right to lease AT&Ts phone lines for network transmission, the divisions ownership was split among RCA, its founding corporate parent General Electric and Westinghouse. NBC officially started broadcasting on November 15,1926, WEAF and WJZ, the flagships of the two earlier networks, were operated side-by-side for about a year as part of the new NBC. On April 5,1927, NBC expanded to the West Coast with the launch of the NBC Orange Network and this was followed by the debut of the NBC Gold Network, also known as the Pacific Gold Network, on October 18,1931. The Orange Network carried Red Network programming, and the Gold Network carried programming from the Blue Network, initially, the Orange Network recreated Eastern Red Network programming for West Coast stations at KPO in San Francisco. The Orange Network name was removed from use in 1936, at the same time, the Gold Network became part of the Blue Network. In the 1930s, NBC also developed a network for shortwave radio stations, in 1927, NBC moved its operations to 711 Fifth Avenue in Manhattan, occupying the upper floors of a building designed by architect Floyd Brown
