Файл: Учебнометодическое пособие по английскому языку для специалистов и бакалавров 2 курса института ртс. Москва 2019.docx
ВУЗ: Не указан
Категория: Не указан
Дисциплина: Не указана
Добавлен: 26.10.2023
Просмотров: 126
Скачиваний: 2
ВНИМАНИЕ! Если данный файл нарушает Ваши авторские права, то обязательно сообщите нам.
Old Fashion Radio
Fessendon invented the Barretter detector which allowed him to also develop amplitude modulation (AM), a radio transmitting technique that allowed multiple transmitters to operate at different frequencies and effectively share the airwaves. So revolutionary was the development of radio by Fessenden and his peers that in 1910 a test transmission was held at the Metropolitan Opera House in New York where Enrico Caruso was performing. This broadcast was heard over 20 miles away by a merchant cargo ship sailing into New York from Europe and reported by the New York Times on January 14th 1910.
The science of radio broadcasting continued at breakneck pace during these early years although consumer uptake remained elusive. A number of audio broadcasts had been transmitted including the ultimatum demand from President Wilson to Germany in 1918 and a highly publicized broadcast from the Naval radio station at Arlington to the Eiffel Tower in France. The end of WWI saw the US government relax control of radio patents and in 1920 KDKA, a Westinghouse owned station in Pittsburgh broadcast coverage of the Harding Cox election. Between commentary they also broadcast other short programs.
Commercial broadcasting took off after this with stations opening in every major city of the US and in major capitals around Europe. The 1920s truly were the birth years of modern radio as we know it. The development of stable mass produced vacuum valves made it possible for almost every home to own a radio. These weren’t small, each radio was fitted into a cabinet that would take pride of place in the family living room and around which the entire family would gather every evening.
Edwin Armstrong, a radio pioneer with the Navy during WWI continued to develop his experiments, and being unhappy with the quality of sound from the AM system which was always known for being a bit flat and prone to white noise and static, he set about reinventing radio broadcasting which resulted in frequency modulation (FM) being made available in 1933. Stations broadcasting in FM were slow to develop given the expense of the new system until the invention of the transistor.
Scientists from Bell Labs invented the transistor in 1947, a technology that transformed modern electronics, although with the huge investments in tubes that already existed it was several years until a commercial transistor radio hit the market. Masaru Ibuka, a young radio repair technician in Japan managed to convince Bell Labs to license the use of the transistor to him for a new radio he wanted to develop. In the US Texas Instruments and Regency were also developing their own transistor powered radios but it wasn’t until 1957, and the release of Sony’s TR-63 AM portable battery powered radio, which at the time was the world’s smallest radio, that radio really became the dominant medium for news and entertainment.
During the 1960s television started to catch up as the preferred medium of entertainment for Americans although radio firmly held on in the car, and by the late 1990s most Americans only listened to the radio in the car or at work, a position radio is set to enjoy for years to come. Despite the advent of satellite and Internet radio, wirelessly broadcasting traffic reports, news, and music to radio receivers is still dominant.
Task 1. Read and translate text C.
Task 2. Answer the following questions.
-
When does the history of radio begin? -
What is a coherer? Who invented it? -
What did Marconi invent in 1894? -
What can you say about Fessendeni’s contribution to radio broadcast development? -
What invention of 1947 transformed modern electronics?
Task 3. Find the information about other inventors who played an important role in radio development and present it to the class.
Text D
Digital television
Digital television (DTV) is the transmission of television signals, including the sound channel, using digital encoding, in contrast to the earlier television technology, analog television, in which the video and audio are carried by analog signals. It is an innovative advance that represents the first significant evolution in television technology since color television in the 1950s. Digital TV transmits in a new image format called HDTV (high definition television), with greater resolution than analog TV, in a wide screen aspect ratio similar to recent movies in contrast to the narrower screen of analog TV. It makes more economical use of scarce radio spectrum space; it can transmit multiple channels, up to 7, in the same bandwidth occupied by a single channel of analog television, and provides many new features that analog television cannot. A transition from analog to digital broadcasting began around 2006 in some countries, and many industrial countries have now completed the changeover, while other countries are in various stages of adaptation. Different digital television broadcasting standards have been adopted in different parts of the world.
Digital Video Broadcasting (DVB) uses coded orthogonal frequency-division multiplexing (OFDM) modulation and supports hierarchical transmission. This standard has been adopted in Europe, Africa, Asia, Australia, total about 60 countries.
Advanced Television System Committee (ATSC) uses eight-level vestigial sideband (8VSB) for terrestrial broadcasting. This standard has been adopted by 6 countries: United States, Canada, Mexico, South Korea, Dominican Republic and Honduras.
Integrated Services Digital Broadcasting (ISDB) is a system designed to provide good reception to fixed receivers and also portable or mobile receivers. It utilizes OFDM and two-dimensional interleaving. It supports hierarchical transmission of up to three layers and uses MPEG-2 video and Advanced Audio Coding. This standard has been adopted in Japan and the Philippines. ISDB-T International is an adaptation of this standard using H.264/MPEG-4 AVC that been adopted in most of South America and is also being embraced by Portuguese-speaking African countries.
Digital Terrestrial Multimedia Broadcasting (DTMB) adopts time-domain synchronous (TDS) OFDM technology with a pseudo-random signal frame to serve as the guard interval (GI) of the OFDM block and the training symbol. The DTMB standard has been adopted in the People's Republic of China, including Hong Kong and Macau.
Digital Multimedia Broadcasting (DMB) is a digital radio transmission technology developed in South Korea as part of the national IT project for sending multimedia such as TV, radio and datacasting to mobile devices such as mobile phones, laptops and GPS navigation systems.
History
Digital TV's roots have been tied very closely to the availability of inexpensive, high performance computers. It wasn't until the 1990s that digital TV became a real possibility.
In the mid-1980s, as Japanese consumer electronics firms forged ahead with the development of HDTV technology, and as the MUSE analog format was proposed by Japan's public broadcaster NHK as a worldwide standard, Japanese advancements were seen as pacesetters that threatened to eclipse U.S. electronics companies. Until June 1990, the Japanese MUSE standard—based on an analog system—was the front-runner among the more than 23 different technical concepts under consideration. Then, an American company, General Instrument, demonstrated the feasibility of a digital television signal. This breakthrough was of such significance that the FCC was persuaded to delay its decision on an ATV standard until a digitally based standard could be developed.
In March 1990, when it became clear that a digital standard was feasible, the FCC made a number of critical decisions. First, the Commission declared that the new ATV standard must be more than an enhanced analog signal, but be able to provide a genuine HDTV signal with at least twice the resolution of existing television images. Then, to ensure that viewers who did not wish to buy a new digital television set could continue to receive conventional television broadcasts, it dictated that the new ATV standard must be capable of being "simulcast" on different channels. The new ATV standard also allowed the new DTV signal to be based on entirely new design principles. Although incompatible with the existing NTSC standard, the new DTV standard would be able to incorporate many improvements.
The final standard adopted by the FCC did not require a single standard for scanning formats, aspect ratios, or lines of resolution. This outcome resulted from a dispute between the consumer electronics industry (joined by some broadcasters) and the computer industry (joined by the film industry and some public interest groups) over which of the two scanning processes—interlaced or progressive—is superior. Interlaced scanning, which is used in televisions worldwide, scans even-numbered lines first, then odd-numbered ones. Progressive scanning, which is the format used in computers, scans lines in sequences, from top to bottom. The computer industry argued that progressive scanning is superior because it does not "flicker" in the manner of interlaced scanning. It also argued that progressive scanning enables easier connections with the Internet, and is more cheaply converted to interlaced formats than vice versa. The film industry also supported progressive scanning because it offers a more efficient means of converting filmed programming into digital formats. For their part, the consumer electronics industry and broadcasters argued that interlaced scanning was the only technology that could transmit the highest quality pictures then (and currently) feasible, i.e., 1,080 lines per picture and 1,920 pixels per line. Broadcasters also favored interlaced scanning because their vast archive of interlaced programming is not readily compatible with a progressive format.
Comparison of analog vs digital
DTV has several advantages over analog TV, the most significant being that digital channels take up less bandwidth, and the bandwidth needs are continuously variable, at a corresponding reduction in image quality depending on the level of compression as well as the resolution of the transmitted image. This means that digital broadcasters can provide more digital channels in the same space, provide high-definition television service, or provide other non-television services such as multimedia or interactivity. DTV also permits special services such as multiplexing (more than one program on the same channel), electronic program guides and additional languages (spoken or subtitled). The sale of non-television services may provide an additional revenue source.
Digital and analog signals react to interference differently. For example, common problems with analog television include ghosting of images, noise from weak signals, and many other potential problems which degrade the quality of the image and sound, although the program material may still be watchable. With digital television, the audio and video must be synchronized digitally, so reception of the digital signal must be very nearly complete; otherwise, neither audio nor video will be usable. Short of this complete failure, "blocky" video is seen when the digital signal experiences interference.
Analog TV began with monophonic sound, and later developed multichannel television sound with two independent audio signal channels. DTV allows up to 5 audio signal channels plus a sub-woofer bass channel, with broadcasts similar in quality to movie theaters and DVDs.
Task 1. Read and translate text D.
Task 2. Answer the following questions.
-
When did a transition from analog to digital broadcasting begin? -
What are the most widely used DTV broadcasting standards? -
What can you say about the history of DTV? -
What advantages does DTV have over analog TV?
Task 3. Study the text. Note ways in which high definition television will be different from existing sets. Compare your answers with your partner.
The aim of high definition television (HDTV) is to provide the viewer with more realistic images than are offered by today’s television sets.
Existing European television pictures are made up of 625 lines, with a total of about 120 000 dots.
In comparison an HD picture consists of 1250 lines and is composed of four times as many dots. This gives greatly increased detail and enhanced colour reproduction.
For HDTV the width/height ratio of the screen has been changed from 4:3 (as in conventional TV) to 16:9, like the screens in cinema. From corner to corner it measures 100-125 cm.
The optimal viewing distance for HDTV is three times the height of the screen compared with seven times the present televisions.
This means your viewing range will be expanded from 10º to 30º. As a result you will have a much greater sense of reality, and may feel that you are there as the action unfolds. HDTV offers you three-dimensional sound, as it uses more speakers than today’s sets.
Feature | Existing | High definition |
no. of lines | 625 | 1,250 |
| | |
Unit 3
Text A
History of mobile phones
Although most of us feel like we couldn't live without our mobile phones, they've not really been in existence for very long. In fact, mobile phones as we know them today have only been around in the last 20 years.
While the transmission of speech by radio has a long history, the first devices that were wireless, mobile, and also capable of connecting to the standard telephone network are much more recent. The first such devices were barely portable compared to today's compact hand-held devices, and their use was clumsy.
Along with the process of developing a more portable technology, and a better interconnections system, drastic changes have taken place in both the networking of wireless communication and the prevalence of its use, with smartphones becoming common globally and a growing proportion of Internet access now done via mobile broadband.
When were mobile phones invented?
Mobile phones, particularly the smartphones that have become our inseparable companions today, are relatively new. However, the history of mobile phones goes back to 1908 when a US Patent was issued in Kentucky for a wireless telephone. Mobile phones were invented as early as the 1940s when engineers working at AT&T developed cells for mobile phone base stations.
The very first mobile phones were not really mobile phones at all. They were two-way radios that allowed people like taxi drivers and the emergency services to communicate. Instead of relying on base stations with separate cells (and the signal being passed from one cell to another), the first mobile phone networks involved one very powerful base station covering a much wider area.
Motorola, on 3 April 1973 were first company to mass produce the first handheld mobile phone. These early mobile phones are often referred to as 0G mobile phones, or Zero Generation mobile phones. Most phones today rely on 3G or 4G mobile technology.
Task 1. Read and translate text A.
Task 2. Discuss the meaning of the words and phrases. Give definitions to these words.
Handheld mobile phone, to communicate, mobile phone networks, the transmission of speech by radio, a colourful screen, handheld devices.
Task 3. Complete the sentences according to the text.
1. The very first mobile phones were two-way radios that allowed people….
2. Instead of relying on base stations with separate cells, the first mobile phone networks involved …
3. The early mobile phones are often referred to…
4. Although most of us feel like we couldn't live without our mobile phones, they've not really been in existence for….
5. The first such devices were barely portable compared to today's compact…
Task 4. Scan the text to mark the statements below true or false.
1. Motorola, on 6 April 1975 were first company to mass produce the first handheld mobile phone.
2. The very first mobile phones were two-way radios that allowed people like taxi drivers and the emergency services to communicate.
3. Instead of relying on base stations with separate cells, the first mobile phone networks involved two very powerful base stations covering a much wider area.
4. The first mobile phones are often referred to as 0G mobile phones, or Zero Generation mobile phones.
Text B
Mobile phone generations
0G refers to mobile radio telephone systems. They were telephone systems of wireless type that preceded the modern cellular mobile form of telephony technology. Since they were the predecessors of the first generation of cellular telephones, these systems are sometimes retroactively referred to as pre-cellular or sometimes zero generation, systems. Technologies used in pre-cellular systems included the Push to Talk (PTT), Mobile Telephone Service (MTS), Improved Mobile Telephone Service (IMTS), and Advanced Mobile Telephone System (AMTS). These early mobile telephone systems can be distinguished from earlier closed radiotelephone systems in that they were available as a commercial service that was part of the public switched telephone network, with their own telephone numbers, rather than part of a closed network such as a police radio or taxi dispatch system.