INSTITUT VA MAKTABLAR UCHUN O’ZBEK TILIDAGI ENG YAXSHI REFERATLAR TO’PLAMI VA INTERAKTIV XIZMATLAR www.doc.uz Two - way radio Radio broadcasts only go one way, from the station to your radio. You can listen to radio. But you can't talk back. Two-way radio lets people talk to each other on radio waves. Police officers and fire fighters use two-way radio. Fire fighters at a big blaze can call for more help on their two-way radios. Soldiers use two-way radios on battlefields. Two-way radios are available in mobile, stationary base and hand-held portable configurations. Hand-held radios are often called walkie-talkies or handie- talkies. A push-to-talk or Press to Transmit button is often present to activate the transmitter. A mobile phone or cellular telephone is an example of a two-way radio that both transmits and receives at the same time (or full-duplex). It uses two different radio frequencies to carry the two directions of the conversation simultaneously. About radio days Radio Days was born out of an interest in all things Old Time Radio, education, and an interest in the World Wide Web. It began in early 1995 and was the first domain specifically dedicated to old time radio. The web site has been featured in many publications including The New York Times, USA Today, CNN and many educational institutions. The mission of this site is to be both an educational tool as well as a historical reference for the various aspects of Old Time Radio including drama, comedy, mystery, and news. How does radio waves get into the air? A radio station sends electrical signals through wires to a tall called a broadcast antenna. Electrical signal get changed into radio waves at the antenna. The antenna sends the radio waves out in all directions. Some radio stations broadcast on AM radio waves. In AM (amplitude modulation) radio transmissions, the amplitude of the combined audio frequency and radio frequency waves varies to match the audio signal. AM radio is subject to problems with static interference. Electromagnetic waves (like radio waves) are produced by the spark discharges in car ignition systems, brushes of electric motors and in all sorts of electrical appliances, as well as in thunderstorms. There is considerable background noise that changes the amplitude of the radio wave signal adding random crackling noises called static. Some programs are broadcast on FM waves, but FM waves make clearer sounds. In FM (frequency modulation) radio transmissions, the frequency of the combined waves changes to reproduce the audio signal. For example, higher frequency is associated with the peak amplitude in the audio wave. FM waves do not have a problem with interference because the noise background does not modify the radio wave frequency. In addition FM waves give better sound reproduction. Plan: 1. About radio days. 2. How do radio waves get into the air? 3. Two-way radio. Personal Pronouns: Agreement with collective nouns The following are examples of collective nouns: audience couple family public class crowd government staff committee faculty group team a) My family is large. It is composed of nine members. When a collective noun refers to a single impersonal unit, a singular pronoun (it, its) is used as in (a). b) My family is loving and supportive. They are always ready to help me. When a collective noun refers to a collection of various individuals, a plural pronoun (they, them, their) is used, as in(b). Using Reflexive Pronouns The following are reflexive pronouns: myself ourselves yourself yourselves himself, herself, itself themselves a) He looked at himself in the mirror. A reflexive pronoun usually refers to the subject of a sentence. In(a): he and himself refer to the same person. b) He himself answered the phone, not his secretary. c) He answered the phone himself. Sometimes reflexive pronouns are used for emphasis, as in(b) and (c). d) She lives by herself The expression by + a reflexive pronoun usually means "alone", as in(d).
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