O’ZBEKISTON ALOQA VA AXBOROTLASHTIRISH AGENTLIGI

TOSHKENT AXBOROT TEXNOLOGIYALARI UNIVERSITETI

CHET TILLAR KAFEDRASI

RADIOTEXNIKA, RADIOESHITTIRISHLAR VA TELEVIDENIYE” YO’NALISHI TALABALARI UCHUN O’QUV USLUBIY QO’LLANMA

5522000 5522100

(INGLIZ TILI)

TOSHKENT 2010

Nigmatova Hilola Abrorovna « RADIOTEXNIKA, RADIOESHITTIRISHLAR VA TELEVIDENIYE” YO’NALISHI TALABALARI UCHUN O’QUV USLUBIY QO’LLANMA»

5522000, 5522100

Ushbu uslubiy qo’llanma “Radiotexnika, radioeshittirishlar va televideniye” yo’nalishi 1-kurs talabalarining auditoriyada va mustaqil ishlashi uchun tuzilgan bo’lib, u 2 ta bo’limdan tashkil topgan. Uslubiy qo’llanmaga raqamli televideniye va radioeshittirishlar sohasiga oid dolzarb matnlarning asl nusxasi kiritilganligi talabalarning ushbu sohaga oid maxsus atamalarni yaxshi o’zlashtirishiga yordam beradi. Matnlarga oid berilgan mashqlar tabalarning ijodiy fikrlash qobiliyatini oshiradi va ularni o’z fikrlarini erkin ifodalashga o’rgatadi. Uslubiy qo’llanmadagi har bir matnga oid kiritilgan mashqlar talabalarni ingliz tili grammatikasini yanada mukammal bilishga va ingliz tilida to’g’ri gapirishga o’rgatadi . Har bir darsga berilgan yangi so’zlarning muqobillari uslubiy qo’llanma bilan ishlashda matnlarni yanada yaxshiroq tushunish imkonini beradi. Keltirilgan mashqlar to’g’ri savol qo’yish va unga javob berish, suhbatdoshini tushunish va muloqat qilishga o’rgatadi. Talabalarning erkin fikrlash va gapirish qobiliyatini, tarjima qilish mahoratini, o’qish texnikasini oshiradi, ularning bilimini mustahkamlaydi.

“Iqtisod va Boshqaruv” fakulteti ilmiy-uslubiy kengashida ko`rib chiqilgan va nashrga tavsiya etilgan ________2010

Taqrizchilar: TATU «chet tillar» kafedrasi

f.f. nomzodi, dotsent Saidqulov Z.K

f.f. nomzodi, professor Iriskulov A.T

Toshkent axborot texnologiyalari universiteti, 2010

CONTENTS

LESSON 1 Radio …………………………………………………….……5

LESSON 2. Uses of Radio Waves ………..……………………..………… 7

LESSON 3. Radio Waves …………………………….…….……….…….10

LESSON 4. AM or FM frequency range………………….……………..... 12

LESSON 5. The electromagnetic spectrum……………………………..…14

LESSON 6 Antennas…………….……………………………..….….….…16

LESSON 7. Differences between AM and FM receivers …….…………..17

LESSON 8 Development of Radio Technology ……………………….…..20

LESSON 9. Digital Radio Engineering …………………..………..……....22

LESSON10. Digital Radio Engineering(2)……………………….…… ..…24

LESSON 11. Digital Radio Engineering(3)………………….………..…....26

LESSON 12. .Processes……………………………………..………..….….29

LESSON 13. Electromagnetic waves ………………..…………….………31

LESSON 14. History of radio .…………………………………….………33

LESSON 15. History of radio. (2)………….……………………… .…..….35

LESSON16. Invention of radio ………………………………..…..………37

HOMEREADING

Invention of radio(2)…………………………………………......................40

Commercialization ……………….………………………………….....…. 40

Uses of radio……………….…..……………….…………….…………........41

Audio ………….............................................................................................. 42

Telephony........................................................................................................42

Video ……………………………………………………….………..……….43

Navigation.……………………………….…………………………………. 43

Radar ………………………………………….…….………..………...….. 44

Data (digital radio)……………………………………..….……………..…44

Radio teletypes…..….…………………………………….…………...….…45

Modern GPS receivers.……………………………………..………………45

Amateur radio service……………………………………………......…..…46

Unlicensed radio services………………………………..….………….……46.

Radio control (RC)……………………..……………………………………47

LESSON 1 RADIO

Task 1. Read and translate the text:

Radio is based on the studies of James Clerk Maxwell, who developed the mathematical theory of electromagnetic waves, and Heinrich Hertz, who devised an apparatus for generating and detecting them. Guglielmo Marconi, recognizing the possibility of using these waves for a wireless communication system, gave a demonstration (1895) of the wireless telegraph, using Hertz's spark coil as a transmitter and Edouard Branly's coherer (a radio detector in which the conductance between two conductors is improved by the passage of a high-frequency current) as the first radio receiver. The effective operating distance of this system increased as the equipment was improved, and in 1901, Marconi succeeded in sending the letter S across the Atlantic Ocean using Morse code. In 1904, Sir John A. Fleming developed the first vacuum electron tube, which was able to detect radio waves electronically. Two years later, Lee de Forest invented the audion, a type of triode, or three-element tube, which not only detected radio waves but also amplified them.

Radios that combine transmitters and receivers are now widely used for communications. Police and military forces and various businesses commonly use such radios to maintain contact with dispersed individuals or groups. Citizens band (CB) radios, two-way radios operating at frequencies near 27 megahertz, most typically used in vehicles for communication while traveling, became popular in the 1970s. Cellular telephones, despite the name, are another popular form of radio used for communication.

Vocabulary

To be based on – asoslangan

developed - rivojlangan

a wave – to’lqin

devised – ishlab chiqilgan

detecting - aniqlash

possibility - imkoniyat

wireless - simsiz

a demonstration – ko’rsatish, namoyish qilish

a spark - uchqun

a coil – simli g’altak

a transmitter - uzatkich

a conductance – o’tkazuvchanlik

a passage - o’tish

high-frequency – yuqori chastota

a current – elektr toki

to increase – oshib bormoq

equipment - jihoz

to succeed in - erishmoq

a tube - naycha

invented – kashf etgan

to amplify - kuchaytirmoq

widely - keng

to maintain – qo’llamoq

dispersed – yo’qolgan

a band - guruh

a vehicle – tashish vositalari

cellular - uyali

despite – shunga qaramasdan

Task 2. Answer the following questions:

1. What is the radio based on?

2. Who developed the mathematical theory of electromagnetic waves?

3. Who devised an apparatus for generating and detecting electromagnetic waves?

4. What and when did Markoni succeed in?

5. What did Sir John A. Fleming develop?

6. When did citizens band (CB) radios and two-way radios become popular?

7. What are cellular telephones?

Task 3. Find the English equivalents of the following word combinations:

elektomagnitli to’lqinlar, simsiz aloqa tizimi, simsiz telegraf, uchqunli faltak, birinchi electron vakum naycha, uch birikmali electron naycha, uzoq masofadagi shaxslar va guruhlar bilan aloqa bog’lashda qo’llamoq, signal uzatuvchi va qabul qiluvchi qurilmalarni o’z ichiga olgan radiolar.

Task 4. Fill in gaps with the words given above and translate sentences:

1. The effective operating ………..of this system increased as ……….was improved, and in 1901, Marconi succeeded in sending the letter S across using Morse code.

2. Radios that combine ………..and ………… are now widely used for communications.

3. Radio is based on …………of James Clerk Maxwell, who developed the mathematical theory of ……………waves, and Heinrich Hertz, who devised an ……..for generating and detecting them.

LESSON 2 Uses of Radio Waves

Task 1. Read and translate the text:

The prime purpose of radio is to convey information from one place to another through the intervening media (i.e., air, space, nonconducting materials) without wires. Besides being used for transmitting sound and television signals, radio is used for the transmission of data in coded form. In the form of radar it is used also for sending out signals and picking up their reflections from objects in their path. Long-range radio signals enable astronauts to communicate with the earth from the moon and carry information from space probes as they travel to distant planets. For navigation of ships and aircraft the radio range, radio compass (or direction finder), and radio time signals are widely used. Radio signals sent from global positioning satellites can also be used by special receivers for a precise indication of position . Digital radio, both satellite and terrestrial, provides improved audio clarity and volume. Various remote-control devices, including rocket and artificial satellite operations systems and automatic valves in pipelines, are activated by radio signals. The development of the transistor and other microelectronic devices led to the development of portable transmitters and receivers. Cellular and cordless telephones are actually radio transceivers. Many telephone calls routinely are relayed by radio rather than by wires; some are sent via radio to relay satellites. Some celestial bodies and interstellar gases emit relatively strong radio waves that are observed with radio telescopes composed of very sensitive receivers and large directional antennas.

Vocabulary

purpose –maqsad

to convey- tashimoq

intervening- aralashuv

nonconducting – noo’tkazgich

wire- sim

besides- bundan tashqari

transmission- axborot jo’natish

pick up – yig’moq

reflection- aks, qaytish

path – yo’l

range - diapozon

enable- imkonga ega

carry - tashimoq

probe- tadqiqot

distant- uzoq

exploration- o’rganish

navigation- suzish va uchishni boshqarish

aircraft - samolyot

direction – yo’nalish

widely – keng

positioning - joylashtirish

satellite-sputnik

a precise- baho

indication- belgilamoq

terrestrial- yerdagi

to provide – ta’minlamoq

improved - yaxshilangan

Various- har xil

Remote- masofadan

Device- qurilma

Artificial- sun’iy

Valve- electron lampa

portable- tashib yurishga qulay

Cellular- uyali

cordless - simsiz

transceiver- qabul qilgich

routinely - rejali

to relay – signal uzatamoq

celestial- astronomik

interstellar -yulduzlararo

emit – chiqarmoq, tarqatmoq

to observe – kuzatmoq, o’rganib chiqmoq

directional-yo’nalishli

Task 2. Answer the following questions:

1. What is the prime purpose of radio?

2. What is radio is used for?

3. What is it used for in the form of radar?

4. How are long-range radio signals used in c?

5. What are the radio range, radio compass and radio time signals widely used for?

6. What kind of radio signals can be used by special receivers for a precise indication of position.

7. What does digital radio provide?

8. What are activated by radio signals?

9. What are the development of the transistor and other microelectronic devices lead to?

Task 3. Find the English equivalents of the following word combinations:

radioning asosiy maqsadi, simsiz, ovozli va television signallarni jo’natish, ma’lumotlarni kodlangan shaklda uzatish, sun’iy yo’ldoshlardan uzatilgan signallar, joylashgan joyini aniqlash uchun, masofadan boshqariluvchi qurilmalar, sun’iy yo’ldoshlarning ishlash tizimi, olib yurishga qulay signal qabul qiluvchi va uzatuvchi qurilmalar, sezuvchan signal qabul qiluvchi qurilmalar

Task 4. Fill in gaps with the words given above and translate sentences:

1. Besides being used for ……….sound and …………….signals, radio is used for the of data in coded form.

2. ……radio signals enable astronauts to ………with the earth from the moon and carry information from ………probes as they ….......to distant planets.

3. Various …………devices, including rocket and artificial satellite operations systems and automatic valves in pipelines, are ………..by radio signals.

LESSON 3 Radio Waves

Task 1. Read and translate the text:

For the propagation and interception of radio waves, a transmitter and receiver are employed. A radio wave acts as a carrier of information-bearing signals; the information may be encoded directly on the wave by periodically interrupting its transmission (as in dot-and-dash telegraphy) or impressed on it by a process called modulation. The actual information in a modulated signal is contained in its sidebands, or frequencies added to the carrier wave, rather than in the carrier wave itself. The two most common types of modulation used in radio are amplitude modulation (AM) and frequency modulation (FM). Frequency modulation minimizes noise and provides greater fidelity than amplitude modulation, which is the older method of broadcasting. Both AM and FM are analog transmission systems, that is, they process sounds into continuously varying patterns of electrical signals which resemble sound waves.

Vocabulary

a propagation- tarqatmoq

an interception- tutmoq

transmitter - uzatgich

to be employed - ishlatilmoq

wave – to’lqin

carrier -tashuvchi

bearing - munosabat

encoded- shifrlangan

directly - bevosita

periodically- davriy ravishda

interrupting- bo’lish

dot-and-dash – nuqta va tire

impressed- ta’sirlangan

modulation-.modulyatsiya

to be contained- o’z ichiga olgan

sidebands- yonlama yolaklar (bokoviye polosa)

frequency- chastota

common -umumiy

amplitude- tebranish

minimize- kamaytirish

provide- ta’minlamoq

fidelity- aniqlik

broadcasting- radioeshittirish

continuously - davomli

varying – o’zgarishlar

patterns- namuna

resemble- eslatmoq, o’xshamoq

Task 2. Answer the following questions:

1. What are a transmitter and receiver employed for?

2. How does a radio wave act?

3. Where is the actual information in a modulated signal contained?

4. What are the two most common types of modulation used in radio?

5. What does frequency modulation do?

6. What kind of systems are AM and FM? How do they process?

Task 3. Find the English equivalents of the following word combinations:

Radio to’lqinlrni tarqatish va tutish, ma’lumotlarga ega signallar, muntazam bo’linib turuvchi, O’zgartirilgan(modulyatsiyalangan) signal, tashuvchi to’lqinlar, tebranishlar modulyatsiyasi, chastotalar modulyatsiyasi, kattaroq aniqlik, radioeshittirishlarning eskiroq usuli, analog xabar uzatish tizimi, tovushlarni qayta ishlash, elektr signallar namunalari.

Task 4. Fill in gaps with the words given above and translate sentences:

1. ………acts as a carrier of ………………signals; the information may be ………….directly on the wave by periodically …………….its transmission (as in dot-and-dash telegraphy) or impressed on it by a …………called modulation.

2. The actual information in a ….signal is contained in its sidebands, or …………..added to the carrier wave, rather than in the wave itself.

3. Frequency modulation …………noise and provides greater fidelity than amplitude………….., which is the older ………..of broadcasting.

LESSON 4 AM or FM frequency range

Task 1. Read and translate the text:

Digital radio uses a transmission system in which the signals propagate as discrete voltage pulses, that is, as patterns of numbers; before transmission, an analog audio signal is converted into a digital signal, which may be transmitted in the AM or FM frequency range. A digital radio broadcast offers compact-disc-quality reception and reproduction on the FM band and FM-quality reception and reproduction on the AM band.

In its most common form, radio is used for the transmission of sounds (voice and music) and pictures (television). The sounds and images are converted into electrical signals by a microphone (sounds) or video camera (images), amplified, and used to modulate a carrier wave that has been generated by an oscillator circuit in a transmitter. The modulated carrier is also amplified, then applied to an antenna that converts the electrical signals to electromagnetic waves for radiation into space. Such waves radiate at the speed of light and are transmitted not only by line of sight but also by deflection from the ionosphere.

Vocabulary

to propagate- tarqatmoq

discrete-

a voltage- kuchlanish

a pattern- namuna

a transmission- xabar jo’natish

to be converted- o’zgartirilgan

a frequency - chastota

a range- diapozon

to broadcast- radio eshittirish qilmoq

a quality – sifat

a band – bog’

a reproduction- qayta ishlash

common- umumiy

amplified - kuchaytirilgan

modulate – modulyatsiya qilmoq, o’zgartirmoq

carrier - tashuvchi

wave – to’lqin

generated- hosil qilingan

oscillator - generator

circuit- electr zanjir

by line of sight -

by deflection- og’ish orqali

Task 2. Answer the following questions:

1. What kind of system does digital radio use?

2. What does a digital radio broadcast offer?

3. What is radio used for?

4. Why are the electrical signals converted into electromagnetic waves?

5. How are waves transmitted ?

6. How do waves radiate?

Task 3. Find the English equivalents of the following word combinations:

Xabar uzatuvchi tizimlar, discrete voltage pulses, analog ovozli signal, raqamli signal, AM FM chastotalar diapozoni, kompakt disk sifati, the FM band ,ovoz va tasvirlarni uzatish, generator elektr zanjiri, elektromagnit to’lqinlar, by line of sight , yorug’lik tezligi.

Task 4. Fill in gaps with the words given above and translate sentences:

1. In radio, this ……….is caused by an …………current in an antenna.

2. Radio frequencies occupy ………….from a few tens of hertz to three hundred gigahertz, although …………..important uses of radio use only a small part of this spectrum.

3. Other types of …………….radiation, with above the RF range, are microwave, infrared, visible light, ultraviolet, and gamma rays.

LESSON 6 ANTENNAS

Task 1. Read and translate the text:

Receiving antennas intercept part of this radiation, change it back to the form of electrical signals, and feed it to a receiver. The most efficient and most common circuit for radio-frequency selection and amplification used in radio receivers is the super heterodyne. In that system, incoming signals are mixed with a signal from a local oscillator to produce intermediate frequencies (IF) that are equal to the arithmetical sum and difference of the incoming and local frequencies. One of those frequencies is applied to an amplifier. Because the IF amplifier operates at a single frequency, namely the intermediate frequency, it can be built for optimum selectivity and gain. The tuning control on a radio receiver adjusts the local oscillator frequency. If the incoming signals are above the threshold of sensitivity of the receiver and if the receiver is tuned to the frequency of the signal, it will amplify the signal and feed it to circuits that demodulate it, i.e., separate the signal wave itself from the carrier wave.

Vocabulary

intercept – bo’lmoq, uzmoq

to feed –yetkazib berish, uzatish

efficient- samarali

common - umumiy

circuit – elektr zanjir

frequency- chastota

selection - tanlov

amplification- kuchaytirish

local - mahalliy

intermediate- oraliq

sum- summa

amplifier- kuchaytirgich

selectivity- tanlash

gain- yig’moq

tuning -sozlash

to adjust- to’g’irlash

threshold - ostona

sensitivity- sezuvchanlik

circuit- elektr zanjir

demodulate – qayta modulatsiyalash

Task 2. Answer the following questions:

1. What are receiving antennas and what do they do?

2. What is the super heterodyne?

3. Why are incoming signals mixed with a signal from a local oscillator?

4. How does the IF amplifier operate?

5. What does the tuning control on a radio receiver do?

6. What will happen if the receiver is tuned to the frequency of the signal?

Task 3. Find the English equivalents of the following word combinations:

Qabul qiluvchi antenna, radio chastotalarni tanlash va kuchaytirish, kelayotgan signal, mahalliy Generatordan kelayotgan signal, yakka chastota, optimal tanlov, sozlashni nazorat qilish, mahalliy generator chastotasi, qabul qiluvchi qurilmaning boshlang’ich sezuvchanligi, signalni kuchaytirish va uzatish.

Task 4. Fill in gaps with the words given above and translate sentences:

1. The most …………….and most common circuit for …………..selection and amplification used in ……………is the super heterodyne.

2. Because the IF amplifier ……..at a single frequency, namely the intermediate, it can be built for optimum selectivity and gain.

3. If the ………signals are above ………….of sensitivity of the receiver and if the receiver is tuned to the frequency of the signal, it will amplify the signal and feed it to circuits that ………..it, i.e., separate the signal wave itself from the carrier wave.

LESSON 7 Differences between AM and FM receivers

Task 1. Read and translate the text:

There are certain differences between AM and FM receivers. In an AM transmission the carrier wave is constant in frequency and varies in amplitude (strength) according to the sounds present at the microphone; in FM the carrier is constant in amplitude and varies in frequency. Because the noise that affects radio signals is partly, but not completely, manifested in amplitude variations, wideband FM receivers are inherently less sensitive to noise. In an FM receiver, the limiter and discriminator stages are circuits that respond solely to changes in frequency. The other stages of the FM receiver are similar to those of the AM receiver but require more care in design and assembly to make full use of FM's advantages. FM is also used in television sound systems. In both radio and television receivers, once the basic signals have been separated from the carrier wave they are fed to a loudspeaker or a display device (usually a cathode-ray tube), where they are converted into sound and visual images, respectively.

Vocabulary

certain - mazkur

transmission- xabar jo’natish

carrier -tashuvchi

wave- to’lqin

constant-doimiy

frequency chastota

to vary- o’zgarish

amplitude- tebranish

strength- kuchaytirish

partly- qisman

completely- butunlay

manifested - aniqlangan

variations- turlar

wideband- keng o’tkazuvchanlik yo’lagi

inherently- uzluksiz

sensitive- sezgir

limiter - chegaralovchi

discriminator- ajratuvchi

stage- bosqich

circuit- elektr zanjir

respond- javob

solely- qat’iyan

to require-talab qilmoq

care – e’tobor

assembly- eshittirish (translyatsiya)

cathode-ray tube- katodli-nurli naycha

respectively- muvofiq, shunga ko’ra

Task 2. Answer the following questions:

1. Are there certain differences between AM and FM receivers?

2. What is constant in an AM transmission in frequency and varies in amplitude?

3. Why are wideband FM receivers inherently less sensitive to noise?

4. What kind of stages are the limiter and discriminator ?

5. What do the other stages of the FM receiver require?

6. Where is FM also used?

7. Where are the basic signals converted into sound and visual images?.

Task 3. Find the English equivalents of the following word combinations:

Doimiy chastota, mikrofonda berilgan ovoz, sezuvchanligi kamroq, chegaralovch va ajratuvchi bosqichlar, chastotadagi o’zgarishlar, FM afzalliklarini to’liq qo’llashni, televideniyedagi ovoz tizimi, ko’rsatuvchi qurilma.

Task 4. Fill in gaps with the words given above and translate sentences:

1. In an …………….the carrier wave is constant in …………and varies in amplitude (strength) according to the sounds present at…………..; in FM the carrier is ………….in amplitude and varies in frequency.

2. The other stages of the ………….are similar to those of the AM receiver but require more care in design and ……………to make full use of FM's advantages.

3. In an FM receiver, the limiter and ……………stages are circuits that ………solely to changes in frequency.

LESSON 8 Development of Radio Technology

Task 1. Read and translate the text:

Radio telephony—the transmission of music and speech—also began in 1906 with the work of Reginald Fessiden and Ernst F. W. Alexanderson, but it was not until Edwin H. Armstrong patented (1913) the circuit for the regenerative receiver that long-range radio reception became practicable. The major developments in radio initially were for ship-to-shore communications. Following the establishment (1920) of station KDKA at Pittsburgh, Pa., the first commercial broadcasting station in the United States, technical improvements in the industry increased, as did radio's popularity. In 1926 the first broadcasting network was formed, ushering in the golden age of radio. Generally credited with creating the first modern broadband FM system, Armstrong built and operated the first FM radio station, KE2XCC, in 1938 at Alpine, N.J. The least expensive form of entertainment during the Great Depression, the radio receiver became a standard household fixture, particularly in the United States. Subsequent research gave rise to countless technical improvements and to such applications as radio facsimile, radar, and television. The latter changed radio programming drastically, and the 1940s and 50s witnessed the migration of the most popular comedy and drama shows from radio to television. Radio programming became mostly music and news and, to a lesser extent, talk shows. The turn of the century saw a potential rebirth for radio as mobile digital radio entered the market with a satellite-based subscription service in Europe (1998) and in the United States (2000). Two years later, a land-based digital radio subscription service was inaugurated in the United States.

Vocabulary

transmission –xabar uzatish

patented- patentlashtirilgan

circuit- elektr zanjir

regenerative – qayta tiklovchi

long-range- uzun diapozon

practicable- haqiqiy, amalda qo’llash

major – ko’pchilik

development- rivojlanish

initially - avvalombor

ship-to-shore –kemadan qirg’oqqa

establishment- o’rnatish

commercial- tijorat

broadcasting- radioeshittirish

improvement-yaxshilash

increased- o’shirilgan

popularity- ommaviylik

formed- shakllantirilgan

ushering- (soprovojdeniye)

to credit- kreditlash

creating- yaratilayotgan

broadband- keng yo’lakli

the least- eng kam

entertainment - kongilochish

household –uy-xo’jalik

fixture- qurlma

particularly- ayniqsa

subsequent

research - tadqiqot

to rise – ko’tarilmoq

countless – son-sanoqsiz

improvement- yaxshi o’zgarish

facsimile- faksimeil

witnessed- guvoh bo’lgan

extent-daraja

rebirth- qayta tug’ilish

satellite-based - sun’iy yo’ldoshlarga asoslangan

subscription service- abonentlik xizmati,

land-based - yerdagi

inaugurated –ochilgan

Task 2. Answer the following questions:

1. When did radio telephony begin?

2. What was the first commercial broadcasting station in the United States?

3. When was the first broadcasting network formed?

4. What did Armstrong build and operate?

5. Why did the radio receiver become a standard household fixture?

6. What gave rise to countless technical improvements?

7. What was the potential rebirth for radio?

Task 3. Find the English equivalents of the following word combinations:

musiqa va nutqni uzatish, uzoq masofada ishlovchi radiopriyomnik , qayta tiklovchi qabul qiluvchi qurilma, texnik o’zgarishlar, birinchi radioeshittiruvchi tarmoq, birinchi zamonaviy keng yo’lakli FM tizimi, uy xojaligidagi standard qurilma, kamroq darajada, sun’iy yo’ldoshlarga asoslangan abonentlik xizmati, raqamli mobil radio, radioning yangi imkoniyati, a potential rebirth for radio.

Task 4. Fill in gaps with the words given above and translate sentences:

1. The ……developments in radio initially were for …………..communications.

2. Subsequent ………..gave rise to countless technical ……….and to such applications as radio…………., radar, and television.

3. The latter changed radio programming…………., and the 1940s and 50s witnessed the …………of the most popular comedy and drama shows from radio to.

LESSON 9 Digital Radio Engineering

Task 1. Read and translate the text:

Digital Radio Technology is powering the conversion from analogue to digital and the deployment of digital radio is moving forward rapidly. Digital Radio Mondiale looks set to transform both the AM and FM bands. DRM is being tested and deployed right across the globe. Digital radio is now available on many platforms or systems and on nearly every broadcast band.

The USA and Japan have developed their own digital radio technology with systems called IBOC and ISDB-T respectively. There are IBOC variants for both the AM and FM bands in both hybrid (analogue and digital signals together) mode and a pure digital mode. IBOC is proving to be a controversial development on the AM bands due to the interference it causes to adjacent channels and via sky waves. It does have a rival called CAM-D . IBOC has been accepted as the standard for these bands so CAM-D is unlikely to become the dominant technology. Russia seems to be also developing a local standard called AVIS now.

Vocabulary

a power- quvvat

conversion- o’zgarish

deployment –yoyilish, foydalanish

forward-oldinga

rapidly- tez

unlikely –ehtimoldan uzoq

to transform-o’zgarmoq

band – bog’

to deploy- yoyilmoq, foydalanmoq

globe- yer shari

available- qo’l etarli, imkoni bor

broadcast- radioeshittirish

respectively – shunga ko’ra

pure -toza

to prove-isbotlamoq

controversial -munozarali

due- tufayli, mos ravishda

interference- aralashuv, shovqin

adjacent- qo’shilgan, qo’shni

via -orqali

a wave- to’lqin

rival -eaqib

to accept- qabul qilmoq

unlikely- oxshamagan

dominant- etakchi

Task 2. Answer the following questions:

1. Where is DRM being tested and deployed?

2. What is digital radio available now?

3. Where is IBOC and ISDB-T developed?

4. What is there in both hybrid mode and a pure digital mode?

5. What is IBOC proving?

6. Does IBOC have a rival?

7. What kind of standard is being developed in Russia now?

Task 3. Find the English equivalents of the following word combinations:

Raqamli radio texnologiyasi, eshittirishlar diapozoni, toza raqamli ish tartibi, qo’shni kanallar va fazoviy to’lqinlar orqali, etakchi texnologiya, mahalliy standard, birinchi radioeshittiruvchi tarmoq, chegaralovch va ajratuvchi bosqichlar.

Task 4. Fill in gaps with the words given above and translate sentences:

1. Digital ………..Technology is powering …………..from analogue to digital and the deployment of digital radio is moving …………..rapidly.

2. There are ………variants for both the AM and FM bands in both …………..(analogue and digital signals together) mode and a pure ………….mode.

3. IBOC has been accepted as ……….for these bands so CAM-D is ……….to become the dominant technology.

LESSON 10 Digital Radio Engineering(2)

Task 1. Read and translate the text:

The roll out of digital radio technology started with the Eureka 147 or Digital Audio Broadcasting (DAB) system. DAB was fortunate that clear spectrum was allocated to it in both Band III ( ~ 220 MHz) and in the L-Band (~ 1.5 GHz) so it never had to have a hybrid or simulcasting mode. There has been worldwide deployment of DAB but the broadcasters and regulators have been criticized in the UK for allowing low bit rates to be used to squeeze in as many stations as possible onto a multiplex. The highest bit rate used in the UK is now 192 kbps on BBC Radio 3 whereas 256 kbps is quite common in other countries. OFCOM UK is promoting DAB strongly and the UK will see an expansion of DAB technology before anything else happens. In the short term there will possibly some use of other digital radio technologies such as DRM and maybe even IBOC.

Engineers are busy working on new DRM and DAB standards that could see DRM+ aimed at Band II and DAB-2 providing better quality audio on Band III. It is entirely possible that DAB-1 will become obsolete very quickly given the current trend in Northern Europe where countries are starting to switch off DAB transmitters. Switzerland and Germany are both testing IBOC and many adjoining countries have shown a great interest in the technology.

Vocabulary

roll out- namoyish etish, taqdim etish,

fortunate- muvaffaqiyatli

clear- aniq

to be allocated- joylashtirilgan

simulcasting- sinxron tarzda yoki bir vaqtda xabar uzatish

worldwide- butun dunyoda

deployment- yoyilish, tarqalish

broadcaster- eshittiruvchi

to be criticized – tanqid qilingan

allow – ruxsat bermoq

rate- meyor

squeeze-siqmoq

common in-

expansion- kengymoq

term - atama

quality – sifat

entirely- butunlay

obsolete- eski

current-tok

trend –an’ana

adjoining- qo’shilgan

Task 2. Answer the following questions:

1. What did the roll out of digital radio technology start?

2. Who has been criticized in the UK?

3. What is the highest bit rate used in the UK?

4. What are engineers doing?

5. What can happen very quickly?

6. What are Switzerland and Germany are doing ?

7. What is the main idea of this text?

Task 3. Find the English equivalents of the following word combinations:

Raqamli texnolodiyalarning namoyish etilishi, aniq spektr, gibrid yoki simulcasting pejim, DABning butun dunyoga yoyilishi, past bitli tezlik, eng katta bitli tezlik, DAB uzatgichlarini o’chirish,

Task 4. Fill in gaps with the words given above and translate sentences:

1. DAB was ………….that clear …………..was allocated to it in both Band III ( ~ 220 MHz) and in the L-Band (~ 1.5 GHz) so it never had to have ……………….or simulcasting mode.

2. OFCOM UK is promoting DAB …………..and the UK will see an expansion of DAB ………………before anything else happens.

3. Engineers are busy …………….on new DRM and DAB …………..that could see DRM+ aimed at Band II and DAB-2 providing better …………..audio on Band III.

LESSON 11 Digital Radio Engineering(3)

Task 1. Read and translate the text:

T-DMB is now gaining ground in Korea, where six multiplex operators have started broadcasting in the capital city, and has been accepted as part of the DAB family that now consists of DAB(digital audio broadcasting), DAB-IP and T-DMB. DAB-IP is used on the national commercial multiplex (Digital One). It looks like China may be developing its own version of an integrated digital system while Canada may jump from DAB to IBOC. Many countries are now deciding on their strategy for digital broadcasting: France has recently opted to use DRM on the AM bands and started testing from Villebon in June 2007; India is going to use DRM and DRM+ to replace transmitters up to 108 MHz. Russia has also indicated that DRM/DRM+ is going to be used extensively throughout this vast region. The publication of the DAB-2 standard that uses the commonplace AAC+ audio encoder should make future receiver design a lot simpler as this is the same encoder used by DRM and IBOC. Germany may adopt this standard in the near future.

There are now three multi-standard receivers on the marketplace: the Technisat Multyradio, the Morphy Richards 27024 and the Himalaya DRM2009. A Russian receiver manufacturer has also produced a prototype DRM receiver at IFA 2007 but it seems that the manufacturing power of China or Japan is going to be required to produce affordable receivers so that the broadcasters will start producing DRM-only programs (the reverse of DAB(digital audio broadcasting) in the UK!). There are now reports that Uniwave is about to produce a DRM (Digital Rights Management) capable radio with a large viewing screen that will display the Journaline application. The latest update is that this receiver is going into mass production in April 2009.

Vocabulary

to gain ground –muvaffaqiyatga erishmoq

broadcasting- radioeshittirish

to accept- qabul qilmoq

commercial- tijorat

to develope- yaratmoq, rivojlantirmoq

integrated - integrallashgan

to opt - tanlamoq

band- bog’, guruh

transmitter- uzatuvchi qurilma

to indicate –ko’rsatmoq

extensively- sezilarli darajada

vast- keng

throughout – hamma yoqda

commonplace- банальность

encoder –kodlovchi qurilma

simpler- oddiyroq

to adopt –qabul qilmoq

marketplace- bozodagi o’rin

prototype- o’xshash namuna

a power - quvvat

to be required- talab etilgan

affordable- imkoni bor

broadcasters-suxandon

report-ma’lumot

capable-qoboliyatga ega

Task 2. Answer the following questions:

1. Where is T-DMB gaining ground now?

2. Where is DAB-IP used?

3. What has France opted to use recently?

4. What has Russia also indicated?

5. How many multi-standard receivers are there on the marketplace?

6. What has a Russian receiver manufacturer produced?

7. What is the latest update?

Task 3. Find the English equivalents of the following word combinations:

muvaffaqiyatga erishmoq, keng ko’lamda foydalanmoq DAB oilasi, integral raqamli tizim, raqamli radioeshittirishlar, qabul qiluvchi qurilmalarning kelgusidagi yangi dizayni , ko’p standardli radiopriyomnik, Xitoy va Japoniyaning ishlab chiqarish quvvati , DRM (Digital Rights Management) qobiliyatiga ega bo’lgan keng ekranli radio.

Task 4. Fill in gaps with the words given above and translate sentences:

…………..is now gaining ground in Korea, where six ………..operators have started broadcasting in the capital city, and has been accepted as part of the …………….that now consists of DAB(digital audio broadcasting), DAB-IP and T-DMB.

There are now three ……….receivers on………….: the Technisat Multyradio, the Morphy Richards 27024 and the Himalaya DRM2009.

The latest ……….is that this ………is going into mass ……………..in April 2009.

LESSON 12 Processes

Task 1. Read and translate the text:

Radio systems used for communications will have the following elements. With more than 100 years of development, each process is implemented by a wide range of methods, specialized for different communications purposes.

Each system contains a transmitter. It consists of a source of electrical energy, producing alternating current of a desired frequency of oscillation. The transmitter contains a system to modulate (change) 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 properties such as amplitude, frequency, phase, or combinations of these properties. The transmitter sends the modulated electrical energy to an antenna; this structure converts the rapidly-changing alternating current into an electromagnetic wave that can move through free space.

Vocabulary

to be implemented- amalgam oshirilgan, qo’llanilgan

wide- keng

a range- diapozon

specialized- maxsuslashtirilgan

a purpose-maqsad

a transmitter- uzatuvchi qurilma

a source - manba

a frequency- chastota

an oscillation-tebranish

to modulate- signallarni o’zgartirmoq, modullashtirmoq

a property -xususiyat

produced- hosil qilingan

subtle – ingichka, nozik

an amplitude- amplituda

a phase- faza

a wave –to’lqin

to turn on /off- yoqmoq, o’chirmoq

Task 2. Answer the following questions:

1. What does each system contain?

2. What does it consist of?

3. What does the transmitter contain?

4. How might this modulation be?

5. What does the transmitter send?

6. Does this structure convert the rapidly-changing alternating current into an electromagnetic wave?

7. How can an electromagnetic wave move?

Task 3. Find the English equivalents of the following word combinations: Radio tizimlari,

100 yillik rivojlanish, usullarning keng diapozoni, turli aloqa maqsadlari uchun maxsuslashtirilgan, elektr energiya manbai, o’zgaruvchan tok, tebranishlarning istalgan chastotasi, nozik xususiyatlar, xusiyatlar yig’indisi, modollashtirilgan elektr energiya, tez o’zgaruvchan o’zgaruvchan tok, elektromagnitik to’lqin, bo’sh fazo orqali.

Task 4. Fill in gaps with the words given above and translate sentences:

1.With more than ……of development, each process is …………….by a wide range of methods, specialized for different …………….purposes.

2.The transmitter ………….a system to modulate (change) some ………..of the energy produced …………..a signal on it.

3.This …………..might be as simple as turning the energy on and off, or altering more subtle properties such as amplitude, frequency, phase, or ………… of these properties.

LESSON 13 Electromagnetic waves

Task 1. Read and translate the text:

Electromagnetic waves travel through space either directly, or have their path altered by reflection, refraction or diffraction. The intensity of the waves diminishes due to geometric dispersion (the inverse-square law); some energy may also be absorbed by the intervening medium in some cases. Noise will generally alter the desired signal; this electromagnetic interference comes from natural sources, as well as from artificial sources such as other transmitters and accidental radiators. Noise is also produced at every step due to the inherent properties of the devices used. If the magnitude of the noise is large enough, the desired signal will no longer be discernible; this is the fundamental limit to the range of radio communications. The electromagnetic wave is intercepted by a receiving antenna; this structure captures some of the energy of the wave and returns it to the form of oscillating electrical currents. At the receiver, these currents are demodulated, which is conversion to a usable signal form by a detector sub-system. The receiver is "tuned" to respond preferentially to the desired signals, and reject undesired signals. Early radio systems relied entirely on the energy collected by an antenna to produce signals for the operator. Radio became more useful after the invention of electronic devices such as the vacuum tube and later the transistor, which made it possible to amplify weak signals. Today radio systems are used for applications from walkie-talkie children's toys to the control of space vehicles, as well as for broadcasting, and many other applications.

Vocabulary

a wave- to’lqin

directly-bevosita

to alter-o’zgarmoq

a reflection- aks

a refraction – sinish(sinish)

a diffraction- difraktsiya(sinish)

intensity- bu yerda: kuch

to diminish -kamaytirmoq

due - sabali

dispersion- dispersiya

an interference- aralashuv

source - manba

artificial –sun’iy

accidental- to’satdan

inherent – o’ziga xos, ajralmas

property- xususiyat

magnitude –kattalik, o’lcham

discernible- sezilarli

fundamental- asosiy

intercepted- uzilgan

oscillating- tebranayotgan

to reject- qaytarmoq

demodulated- qayta modullshtirish

sub-system- qo’shimcha tizim

undesired - istalmagan

a tube- trubka

vehicle- transport vositalari

Task 2. Answer the following questions:

1. How do electromagnetic waves travel?

2. How does the intensity of the waves diminish?

3. Where does this electromagnetic interference come from?

4. What kind of artificial sources do you know?

5. Where noise is also produced?

6. What is the fundamental limit to the range of radio communications?

7. What is the electromagnetic wave intercepted by?

8. What happens at the receiver?

9. When did radio become more useful?

10. Where are radio systems used today?

Task 3. Find the English equivalents of the following word combinations:

Electomagnit shovqin, xalaqit, geometric dispersiyaya tufayli due to geometric dispersion, Oraliq masofa, istalgan signal, kerakli signal, tabiiy manbalar, sun’iy manbalar, qurilmaning o’ziga xos xususiyatlari, tebranuvchi elektr toki, foydalanishga yaroqli signal shakli,javob bermoq, keraksiz signallarni qytarish, oldingi radiosignallar, electron qurilma, fazodagi transport vositalarini boshqarish, bolalarning masofadan boshqariluvchi o’yinchoqlari, kuchsiz signallarni kuchaytirish.

Task 4. Fill in gaps with the words given above and translate sentences:

Noise will generally alter the …………..signal; this electromagnetic ………….comes from natural sources, as well as from ………..sources such as other transmitters and accidental radiators.

The electromagnetic wave is ……………by a receiving antenna; this ………captures some of the energy of the wave and …………….it to the form of electrical currents.

Radio became more useful after ………….of electronic devices such as the vacuum tube and later the transistor, which made it possible to amplify weak signals.

LESSON 14 History of radio.

Task 1. Read and translate the text:

The pre-history and early history of radio is the history of technology that produced radio instruments that use radio waves. Within the timeline of radio, many people contributed theory and inventions in what became radio. Radio development began as "wireless telegraphy". Later radio history increasingly involves matters of programming and content. Who invented the radio?

In the history of radio and development of "wireless telegraphy", several people are claimed to have "invented the radio" leading to a great radio controversy. The most commonly accepted claims are:

Guglielmo Marconi, who equipped ships with life-saving wireless communications, conducted a reported transatlantic radio communications experiments in 1901 and established the first commercial transatlantic radio service in 1907.

Nikola Tesla, who developed means to reliably produce radio frequency currents, publicly demonstrated the principles of radio, and transmitted long distance signals. In 1943 the US Supreme Court upheld Tesla's patent number U.S. Patent 645,576.

The reason it is not obvious who invented radio is that the technology is a product of many different discoveries and developments.

Vocabulary

Wave- to’lqin

timeline- bu erda: rivojlanish mobaynida

to contribute- hissa qo’shmoq

increasingly-

to involve-jalb etmoq

to invent- kashf etmoq

leading – etakchi

to accept-qabul qilmoq

to claim –talab qilmoq, o’z xuquqlarini e’lon qilmoq

equipped- jihozlangan

wireless - simsiz

conducted –o’tkazuvchan

to establish- o’rnatmoq

to develop -yaratmoq

reliably- ishonchli

frequency - chastota

publicly- публично

to demonstrate- namoyish etmoq

obvious- очевидный

Task 2. Answer the following questions:

1. What kind of history is the history of radio?

2. How did radio development begin?

3. What are people claimed to have?

4. What are the most commonly accepted claims?

5. What did Nikola Tesla do?

6. What kind of product is a radio technology

Task 3. Find the English equivalents of the following word combinations:

The pre-history and early history of radio technologiya tarixi, radioto’lqinlardan foydalanish, radioning vaqt shkalasi, radioning yaratilishi simsiz telegraf, dasturlash ishlari, radio haqidagi yirik bahslar, qutqaruvsh ishlari uchun qo’llaniladigan simsiz aloqa vositalari, atlantika bo’ylab radioaloqalar tajribalari, atlantika boylab birinch tijorat radio xizmati, ishonchli radiochastotali tokhosil qiluvchi vositalar uzoq masofadan olinadigan signallar, har xil kashfiyotlar va rivojlanishlar.

Task 4. Fill in gaps with the words given above and translate sentences:

Radio …………..began as "wireless telegraphy". Later radio history ……………involves matters of ……………and content.

Guglielmo Marconi, who equipped ships with ………..wireless communications, conducted a reported ………….radio communications ………….in 1901.

…………..it is not obvious who invented radio is that the technology is a product of many different …………and developments.

LESSON 15 History of radio. (2)

Task 1. Read and translate the text:

Various scientists proposed that electricity and magnetism, both capable of causing attraction and repulsion of objects, were linked. In 1802 Gian Domenico Romagnosi suggested the relationship between electric current and magnetism, but his reports went unnoticed. In 1820 Hans Christian Ørsted performed a widely known experiment on man-made electric current and magnetism. He demonstrated that a wire carrying a current could deflect a magnetized compass needle. Ørsted's experiments discovered the relationship between electricity and magnetism in a very simple experiment. Ørsted's work influenced André-Marie Ampère to produce a theory of electromagnetism. During its early development and long after wide use of the technology, disputes persisted as to who could claim sole credit for this obvious boon to mankind. Closely related, radio was developed along with two other key inventions, the telegraph and the telephone.

Vocabulary

various- turli

a scientist- olim

proposed-

capable- qobiliyatli

repulsion - itarish

to suggest- maslahat bermoq

relationship- aloqa, bog’lqlik

current - tok

to report- ma’lumot bermoq

unnoticed- e’tibor qilinmagan

performed –amalga oshirilgan

widely – keng ko’lamda

demonstrated – namoyish etilgan

wire – sim

to deflect- og’dirmoq

dispute- bahs

to persist –saqlanib qolgan

claim- talab

sole - yagona

boon- yaxshilanish, foydali narsa.

mankind- insoniyat

related- bog’liq

invention- kashfiyot

Task 2. Answer the following questions:

1. What did various scientists propose?

2. What and when did Gian Domenico Romagnosi suggest?

3. What and when did Hans Christian Ørsted perform?

4. What did he demonstrated?

5. What did Ørsted's experiments discovered?

6. What did Ørsted's work influence?

7. How was radio developed?

Task 3. Find the English equivalents of the following word combinations:

jismlarning tortilishi va itarilishi,elektr toki va magnitizm orasidagi bog’liqlik,

inson qo’li bilan yaratilgan elektr toki va magnetism, tokni o’tkazuvchi sim , magnitlangan compass ignasini qimirlatmoq, elektromagnetizm nazariyasi, insoniyat uchun foydali.

Task 4. Fill in gaps with the words given above and translate sentences:

………..Gian Domenico Romagnosi ………………the relationship between electric current and………., but his reports went unnoticed.

Ørsted's experiments ……………..the relationship between and magnetism in a very simple………..

During its early ………..and long after wide use of……………., disputes persisted as to who could …………..sole credit for this obvious boon to mankind.

LESSON 16 Invention of radio

Task 1. Read and translate the text:

The meaning and usage of the word "radio" has developed in parallel with developments within the field and can be seen to have three distinct phases: electromagnetic waves and experimentation; wireless communication and technical development; and radio broadcasting and commercialization. Many individuals -- inventors, engineers, developers, businessmen -- contributed to produce the modern idea of radio and thus the origins and 'invention' are multiple and controversial. Early radio could not transmit sound or speech and was called the "wireless telegraph".

Development from a laboratory demonstration to an commercial entity spanned several decades and required the efforts of many practitioners. Experiments, later patented, were undertaken by Thomas Edison and his employees of Menlo Park. Edison applied in 1885 to the U.S. Patent Office for his patent on a electrostatic coupling system between elevated terminals. The patent was granted as U.S. Patent 465,971 on December 29, 1891. The Marconi Company would later purchase rights to the Edison patent to protect them legally from lawsuits.

Vocabulary

to develope -rivojlanmoq

distinct-aniq

phase-faza

wave- to’lqin

wireless- simsiz

development- rivojlanish

broadcasting- radioeshittirish

commercialization-

individuals – jismoniy shaxslar

inventor- kashfiuotchilar

to contribute- hissa qo’shmoq

entity - obyekt

spanned- to’ldirilgan

decades –o’n yilliklar

required- talab etilgan

efforts - harakatlar

practitioners- amaliyotchilar

undertaken-qabul qilingan, qo’llangan

employees -ishchilar

applied- qo’llangan

coupling-ilintirmoq

to grant -tanitmoq

purchase- xarid

legally-qonuniy

lawsuit.-sud jarayoni

Task 2. Answer the following questions:

1. When has the meaning and usage of the word "radio" developed?

2. Who contributed to produce the modern idea of radio?

3. Why was early radio called the "wireless telegraph"?

4. What did development from a laboratory demonstration to an commercial entity span and require?

5. Who were later patented experiments undertaken by?

6. What did Edison apply in 1885?

7. When was the patent granted?

Task 3. Find the English equivalents of the following word combinations:

ahamiyati va qo’llanilishi, uchta aniq faza, electromagnetic to’lqinlar va tajriba o’tkazish ;

simsiz aloqa va texnik jihatdan yaratilishi, radioeshittirish va tijoratlashtirish, radio haqidagi zamonaviy g’oyalar, ko’p va munozarali, tovush va nutqni jo’natish, ko’p amaliyotchilarning urinishlari , Edison patenti huquqlari

Task 4. Fill in gaps with the words given above and translate sentences:

Many …………-- inventors, engineers, developers, businessmen -- ……………..to produce the modern idea of radio and thus the origins and 'invention' are …………and…………….

Development from ……………demonstration to an commercial entity …………several decades and …………..the efforts of many practitioners.

The Marconi Company would later rights to the Edison patent them legally from lawsuits.

II PART

HOMEREADING

Invention of radio

Tesla demonstrating wireless transmissions during his high frequency and potential lecture of 1891. After continued research, Tesla presented the fundamentals of radio in 1893.

In 1893, in St. Louis, Missouri, Nikola Tesla made devices for his experiments with electricity. Addressing the Franklin Institute in Philadelphia and the National Electric Light Association, he described and demonstrated the principles of his wireless work. The descriptions contained all the elements that were later incorporated into radio systems before the development of the vacuum tube. He initially experimented with magnetic receivers, unlike the coherers (detecting devices consisting of tubes filled with iron filings which had been invented by Temistocle Calzecchi-Onesti at Fermo in Italy in 1884) used by Guglielmo Marconi and other early experimenters.

A demonstration of wireless telegraphy took place in the lecture theater of the Oxford University Museum of Natural History on August 14, 1894, carried out by Professor Oliver Lodge and Alexander Muirhead. During the demonstration a radio signal was sent from the neighboring Clarendon laboratory building, and received by apparatus in the lecture theater.

In 1895 Alexander Stepanovich Popov built his first radio receiver, which contained a coherer. Further refined as a lightning detector, it was presented to the Russian Physical and Chemical Society on May 7, 1895. A depiction of Popov's lightning detector was printed in the Journal of the Russian Physical and Chemical Society the same year. Popov's receiver was created on the improved basis of Lodge's receiver, and originally intended for reproduction of its experiments.

Commercialization

In 1896, Marconi was awarded the British patent 12039, Improvements in transmitting electrical impulses and signals and in apparatus there-for, for radio. In 1897 he established a radio station on the Isle of Wight, England. Marconi opened his "wireless" factory in Hall Street, Chelmsford, England in 1898, employing around 50 people.

The next advancement was the vacuum tube detector, invented by Westinghouse engineers. On Christmas Eve, 1906, Reginald Fessenden used a synchronous rotary-spark transmitter for the first radio program broadcast, from Ocean Bluff-Brant Rock, Massachusetts. Ships at sea heard a broadcast that included Fessenden playing O Holy Night on the violin and reading a passage from the Bible. This was, for all intents and purposes, the first transmission of what is now known as amplitude modulation or AM radio. The first radio news program was broadcast August 31, 1920 by station 8MK in Detroit, Michigan, which survives today as all-news format station WWJ under ownership of the CBS network. The first college radio station began broadcasting on October 14, 1920, from Union College, Schenectady, New York under the personal call letters of Wendell King, an African-American student at the school.[6] That month 2ADD, later renamed WRUC in 1940, aired what is believed to be the first public entertainment broadcast in the United States, a series of Thursday night concerts initially heard within a 100-mile (160 km) radius and later for a 1,000-mile (1,600 km) radius. In November 1920, it aired the first broadcast of a sporting event.[6][7] At 9 pm on August 27, 1920, Sociedad Radio Argentina aired a live performance of Richard Wagner's Parsifal opera from the Coliseo Theater in downtown Buenos Aires. Only about twenty homes in the city had receivers to tune in this radio program. Meanwhile, regular entertainment broadcasts commenced in 1922 from the Marconi Research Centre at Writtle, England.

Uses of radio

Early uses were maritime, for sending telegraphic messages using Morse code between ships and land. The earliest users included the Japanese Navy scouting the Russian fleet during the Battle of Tsushima in 1905. One of the most memorable uses of marine telegraphy was during the sinking of the RMS Titanic in 1912, including communications between operators on the sinking ship and nearby vessels, and communications to shore stations listing the survivors.

Radio was used to pass on orders and communications between armies and navies on both sides in World War I; Germany used radio communications for diplomatic messages once it discovered that its submarine cables had been tapped by the British. The United States passed on President Woodrow Wilson's Fourteen Points to Germany via radio during the war. Broadcasting began from San Jose, California in 1909], and became feasible in the 1920s, with the widespread introduction of radio receivers, particularly in Europe and the United States. Besides broadcasting, point-to-point broadcasting, including telephone messages and relays of radio programs, became widespread in the 1920s and 1930s. Another use of radio in the pre-war years was the development of detection and locating of aircraft and ships by the use of radar (Radio Detection And Ranging).

Today, radio takes many forms, including wireless networks and mobile communications of all types, as well as radio broadcasting. Before the advent of television, commercial radio broadcasts included not only news and music, but dramas, comedies, variety shows, and many other forms of entertainment. Radio was unique among methods of dramatic presentation in that it used only sound.

Audio

AM radio uses amplitude modulation, in which the amplitude of the transmitted signal is made proportional to the sound amplitude captured (transduced) by the microphone, while the transmitted frequency remains unchanged. Transmissions are affected by static and interference because lightning and other sources of radio emissions on the same frequency add their amplitudes to the original transmitted amplitude. In the early part of the 20th century, American AM radio stations broadcast with powers as high as 500 kW, and some could be heard worldwide; these stations' transmitters were commandeered for military use by the US Government during World War II. Currently, the maximum broadcast power for a civilian AM radio station in the United States and Canada is 50 kW, and the majority of stations that emit signals this powerful were grandfathered in; these include WGN (AM), WJR, KGA at 50 kW. In 1986 KTNN received the last granted 50,000 watt license. These 50 kW stations are generally called "clear channel" stations (Not to be confused with the Clear channel radio conglomerate), because within North America each of these stations has exclusive use of its broadcast frequency throughout part or all of the broadcast day.

Telephony

Mobile phones transmit to a local cell site (transmitter/receiver) that ultimately connects to the public switched telephone network (PSTN) through an optic fiber or microwave radio and other network elements. When the mobile phone nears the edge of the cell site's radio coverage area, the central computer switches the phone to a new cell. Cell phones originally used FM, but now most use various digital modulation schemes. Recent developments in Sweden (such as DROPme) allow for the instant downloading of digital material from a radio broadcast (such as a song) to a mobile phone.

Satellite phones use satellites rather than cell towers to communicate.

Video

Television sends the picture as AM and the sound as AM or FM, with the sound carrier a fixed frequency (4.5 MHz in the NTSC system) away from the video carrier. Analog television also uses a vestigial sideband on the video carrier to reduce the bandwidth required.

Digital television uses 8VSB modulation in North America (under the ATSC digital television standard), and COFDM modulation elsewhere in the world (using the DVB-T standard). A Reed–Solomon error correction code adds redundant correction codes and allows reliable reception during moderate data loss. Although many current and future codecs can be sent in the MPEG-2 transport stream container format, as of 2006 most systems use a standard-definition format almost identical to DVD: MPEG-2 video in Anamorphic widescreen and MPEG layer 2 (MP2) audio. High-definition television is possible simply by using a higher-resolution picture, but H.264/AVC is being considered as a replacement video codec in some regions for its improved compression. With the compression and improved modulation involved, a single "channel" can contain a high-definition program and several standard-definition programs.

Navigation

All satellite navigation systems use satellites with precision clocks. The satellite transmits its position, and the time of the transmission. The receiver listens to four satellites, and can figure its position as being on a line that is tangent to a spherical shell around each satellite, determined by the time-of-flight of the radio signals from the satellite. A computer in the receiver does the math.

Radio direction-finding is the oldest form of radio navigation. Before 1960 navigators used movable loop antennas to locate commercial AM stations near cities. In some cases they used marine radiolocation beacons, which share a range of frequencies just above AM radio with amateur radio operators. LORAN systems also used time-of-flight radio signals, but from radio stations on the ground. VOR (Very High Frequency Omnidirectional Range), systems (used by aircraft), have an antenna array that transmits two signals simultaneously. A directional signal rotates like a lighthouse at a fixed rate. When the directional signal is facing north, an omnidirectional signal pulses. By measuring the difference in phase of these two signals, an aircraft can determine its bearing or radial from the station, thus establishing a line of position. An aircraft can get readings from two VORs and locate its position at the intersection of the two radials, known as a "fix." When the VOR station is collocated with DME (Distance Measuring Equipment), the aircraft can determine its bearing and range from the station, thus providing a fix from only one ground station. Such stations are called VOR/DMEs. The military operates a similar system of navaids, called TACANs, which are often built into VOR stations. Such stations are called VORTACs. Because TACANs include distance measuring equipment, VOR/DME and VORTAC stations are identical in navigation potential to civil aircraft.

Radar

Radar (Radio Detection And Ranging) detects objects at a distance by bouncing radio waves off them. The delay caused by the echo measures the distance. The direction of the beam determines the direction of the reflection. The polarization and frequency of the return can sense the type of surface. Navigational radars scan a wide area two to four times per minute. They use very short waves that reflect from earth and stone. They are common on commercial ships and long-distance commercial aircraft.

General purpose radars generally use navigational radar frequencies, but modulate and polarize the pulse so the receiver can determine the type of surface of the reflector. The best general-purpose radars distinguish the rain of heavy storms, as well as land and vehicles. Some can superimpose sonar data and map data from GPS position.

Search radars scan a wide area with pulses of short radio waves. They usually scan the area two to four times a minute. Sometimes search radars use the Doppler effect to separate moving vehicles from clutter. Targeting radars use the same principle as search radar but scan a much smaller area far more often, usually several times a second or more. Weather radars resemble search radars, but use radio waves with circular polarization and a wavelength to reflect from water droplets. Some weather radar use the Doppler effect to measure wind speeds.

Data (digital radio)

Most new radio systems are digital, see also: Digital TV, Satellite Radio, Digital Audio Broadcasting. The oldest form of digital broadcast was spark gap telegraphy, used by pioneers such as Marconi. By pressing the key, the operator could send messages in Morse code by energizing a rotating commutating spark gap. The rotating commutator produced a tone in the receiver, where a simple spark gap would produce a hiss, indistinguishable from static. Spark gap transmitters are now illegal, because their transmissions span several hundred megahertz. This is very wasteful of both radio frequencies and power.

The next advance was continuous wave telegraphy, or CW (Continuous Wave), in which a pure radio frequency, produced by a vacuum tube electronic oscillator was switched on and off by a key. A receiver with a local oscillator would "heterodyne" with the pure radio frequency, creating a whistle-like audio tone. CW uses less than 100 Hz of bandwidth. CW is still used, these days primarily by amateur radio operators (hams). Strictly, on-off keying of a carrier should be known as "Interrupted Continuous Wave" or ICW or on-off keying (OOK).

Radio teletypes

Radio teletypes usually operate on short-wave (HF) and are much loved by the military because they create written information without a skilled operator. They send a bit as one of two tones. Groups of five or seven bits become a character printed by a teletype. From about 1925 to 1975, radio teletype was how most commercial messages were sent to less developed countries. These are still used by the military and weather services.

Aircraft use a 1200 Baud radioteletype service over VHF to send their ID, altitude and position, and get gate and connecting-flight data. Microwave dishes on satellites, telephone exchanges and TV stations usually use quadrature amplitude modulation (QAM). QAM sends data by changing both the phase and the amplitude of the radio signal. Engineers like QAM because it packs the most bits into a radio signal when given an exclusive (non-shared) fixed narrowband frequency range. Usually the bits are sent in "frames" that repeat. A special bit pattern is used to locate the beginning of a frame.

Modern GPS receivers.

Communication systems that limit themselves to a fixed narrowband frequency range are vulnerable to jamming. A variety of jamming-resistant spread spectrum techniques were initially developed for military use, most famously for Global Positioning System satellite transmissions. Commercial use of spread spectrum began in the 1980s. Bluetooth, most cell phones, and the 802.11b version of Wi-Fi each use various forms of spread spectrum.

Systems that need reliability, or that share their frequency with other services, may use "coded orthogonal frequency-division multiplexing" or COFDM. COFDM breaks a digital signal into as many as several hundred slower subchannels. The digital signal is often sent as QAM on the subchannels. Modern COFDM systems use a small computer to make and decode the signal with digital signal processing, which is more flexible and far less expensive than older systems that implemented separate electronic channels. COFDM resists fading and ghosting because the narrow-channel QAM signals can be sent slowly. An adaptive system, or one that sends error-correction codes can also resist interference, because most interference can affect only a few of the QAM channels. COFDM is used for Wi-Fi, some cell phones, Digital Radio Mondiale, Eureka 147, and many other local area network, digital TV and radio standards.

Amateur radio service

Amateur radio, also known as "ham radio", is a hobby in which enthusiasts are licensed to communicate on a number of bands in the radio frequency spectrum non-commercially and for their own enjoyment. They may also provide emergency and public service assistance. This has been very beneficial in emergencies, saving lives in many instances. Radio amateurs use a variety of modes, including nostalgic ones like morse code and experimental ones like Low-Frequency Experimental Radio. Several forms of radio were pioneered by radio amateurs and later became commercially important including FM, single-sideband (SSB), AM, digital packet radio and satellite repeaters. Some amateur frequencies may be disrupted by power-line internet service.

Unlicensed radio services

Unlicensed, government-authorized personal radio services such as Citizens' band radio in Australia, the USA, and Europe, and Family Radio Service and Multi-Use Radio Service in North America exist to provide simple, (usually) short range communication for individuals and small groups, without the overhead of licensing. Similar services exist in other parts of the world. These radio services involve the use of handheld units.

Free radio stations, sometimes called pirate radio or "clandestine" stations, are unauthorized, unlicensed, illegal broadcasting stations. These are often low power transmitters operated on sporadic schedules by hobbyists, community activists, or political and cultural dissidents. Some pirate stations operating offshore in parts of Europe and the United Kingdom more closely resembled legal stations, maintaining regular schedules, using high power, and selling commercial advertising time.

Radio control (RC)

Radio remote controls use radio waves to transmit control data to a remote object as in some early forms of guided missile, some early TV remotes and a range of model boats, cars and airplanes. Large industrial remote-controlled equipment such as cranes and switching locomotives now usually use digital radio techniques to ensure safety and reliability.

In Madison Square Garden, at the Electrical Exhibition of 1898, Nikola Tesla successfully demonstrated a radio-controlled boat. He was awarded U.S. patent No. 613,809 for a "Method of and Apparatus for Controlling Mechanism of Moving Vessels or Vehicles."

Nigmatova Hilola Abrorovna

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