Vocabulary

3.2 Complete the vocabulary (term) log, i.e. find out definition, part of speech, translation, synonyms and antonyms if possible, decode abbreviations.

Grammar

3.3 Choose the right variant to complete the sentences.

1) The water that has been purified is ______________ (distilled water / distilling water). 2) A device that has been adjusted for errors is a ______________ (calibrating instrument / calibrated instrument). 3) A device that adjusts other instruments is a _______________ (calibrating instrument / calibrated instrument). 4. A bar that attaches one moving part of a machine to another one is a __________ (connecting rod / connected rod). 5) A wire that is covered with a nonconductor is an _________ (insulated wire / insulating wire). 6) You may choose any _________ (viewing device / viewed device) you like. 7) She is sure to get the job she wants. She is a very ___________ (determined person / determining person). 8) She was an _________ (inspired example / inspiring example) to her followers.

Comprehension Check

3.4 Make up no less than 10 questions.

3.5 Read the following text and write a summary to it (no less than 7 sentences) in Russian and English.

Text 2 Digital TV

Simply put, digital TV is a way of receiving your television signal in a digital format. This allows TV companies to broadcast better quality sound, a higher definition picture and a wider range of channels than ever before.

The digital switchover in the UK is already complete. If you feel you were just swept along with the change and have questions, why not check out our handy guide to digital television services? It is full of useful answers to frequently asked digital TV questions.

As well as better quality picture and sound, and more channels, digital television has many other advantages over its analogue predecessor.

One such advantage is the interactive nature of the service. Digital TV allows users to access further information by entering menus and interacting with their television in ways they had never even dreamed of before. In addition to this, viewers can listen to radio channels via their televisions and even watch archived programs via digital ‘on-demand’ services.

More modern digital TV services will also allow you to access the internet via your television set.

There is more than one type of digital television service. Here is a brief lowdown on the types you are likely to encounter.

Digital terrestrial - this is a popular form of digital television for people who are upgrading from analogue to digital services. Relatively hassle free, digital terrestrial TV is received via your existing TV aerial, ensuring minimal disruption to your TV viewing and little extra cost.

Free view is the most common form of digital terrestrial TV and is accessed via a simple set top box, which can be purchased with a one off payment at many high street stores. These can cost as little as £15. Free view gives you access to 50 digital television channels and 20 digital radio channels, giving you a wide selection of digital programming. If you would prefer even more choice, Top-Up TV Anytime gives you access to these channels and more with a small subscription fee.

Digital satellite TV. As you can probably guess, this refers to digital television which is received via a satellite dish and is a popular option for those whose property already has such a dish fitted. If you do not have an existing dish on your property, it is necessary to have one installed before you can receive digital satellite TV, although you must first obtain permission from your property owner if you are renting.

There are no geographical restrictions on this service as the digital TV signal is beamed directly from satellites orbiting overhead. As a result, this service is useful if you are unable to get a strong free view signal in your area.

Freesat is the satellite equivalent to free view and requires a one off payment for a Freesat box and satellite dish. As this tends to be somewhat more expensive than simply purchasing a free view box, Freesat throw in a whole lot more channels for your money, over 140 in total.

As with Free view, this package does not include any of the major sports channels.

You can also receive digital satellite TV from Sky. Sky’s service requires a subscription, although this subscription will often include the installation of a satellite dish if you do not already have one, and the provision of a Sky Box.

Sky also provide their own Freesat service which offers 240 digital TV channels and 85 digital radio stations without requiring the user to sign up to a subscription.

Digital cable TV is delivered via a network of high speed fiber optic cables. The most popular provider of digital cable TV is Virgin Media, whose TiVo box caused a storm by allowing people far greater freedom to choose how they watch TV than ever before. TiVo allowed users to pause and rewind live TV, as well as giving them access to on demand content and the ability create their own channels by ‘teaching’ TiVo which types of programs they like to watch.

While the picture quality is fantastic, the services innovative and the range of channels outstanding, this method of receiving digital TV is not currently available everywhere. Virgin Media are currently rolling their services out to an increasing proportion of the country, but this is likely to take some time.

Telephone line digital TV - this simply refers to digital television delivered to a user via a telephone line. BT Vision is a prime example of this, although this service is only offered to existing BT phone or broadband customers.

Internet protocol television, otherwise known as IPTV, internet protocol television uses a broadband connection to provide digital television services to your home. Such services include YouView, Google TV and – of course – Apple TV.

Customers of these services can either opt in to a subscription, which gives them access to libraries of archived content online, or simply pay a one off fee for a set top box.

All sorts of extra features and services are available to digital TV customers, ranging from subtitles and audio descriptions to detailed literature on which method of receiving digital TV will work best for you. Such support offers peace of mind to those venturing into the world of digital TV for the first time.

Unit 4 What is radio?

4.1 Read and translate the texts. Use a dictionary to help you.

Text 1 What is radio?

You might think "radio" is a gadget you listen to, but it also means something else. Radio means sending energy with waves. In other words, it is a method of transmitting electrical energy from one place to another without using any kind of direct, wired connection. That is why it is often called wireless. The equipment that sends out a radio wave is known as a transmitter; the radio wave sent by a transmitter whizzes through the air—maybe from one side of the world to the other—and completes its journey when it reaches a second piece of equipment called a receiver.

When you extend the antenna (aerial) on a radio receiver, it snatches some of the electromagnetic energy passing by. Tune the radio into a station and an electronic circuit inside the radio selects only the program you want from all those that are broadcasting.

How radio waves travel from a transmitter to a receiver. Electrons rush up and down the transmitter, shooting out radio waves. The radio waves travel through the air at the speed of light. When the radio waves hit a receiver, they make electrons vibrate inside it, recreating the original signal. This process can happen between one powerful transmitter and many receivers—which is why thousands or millions of people can pick up the same radio signal at the same time.

How does this happen? The electromagnetic energy, which is a mixture of electricity and magnetism, travels past you in waves like those on the surface of the ocean. These are called radio waves. Like ocean waves, radio waves have a certain speed, length, and frequency. The speed is simply how fast the wave travels between two places. The wavelength is the distance between one crest (wave peak) and the next, while the frequency is the number of waves that arrive each second. Frequency is measured with a unit called hertz, so if seven waves arrive in a second, we call that seven-hertz (7 Hz). If you have ever watched ocean waves rolling in to the beach, you will know they travel with a speed of maybe one meter (three feet) per second or so. The wavelength of ocean waves tends to be tens of meters or feet, and the frequency is about one wave every few seconds.

When your radio sits on a bookshelf trying to catch waves coming into your home, it is a bit like you standing by the beach watching the breakers rolling in. Radio waves are much faster, longer, and more frequent than ocean waves, however. Their wavelength is typically hundreds of meters—so that is the distance between one wave crest and the next. Nevertheless, their frequency can be in the millions of hertz—so millions of these waves arrive each second. If the waves are hundreds of meters long, how can millions of them arrive so often? It is simple. Radio waves travel unbelievably fast—at the speed of light (300,000 km or 186,000 miles per second).

Analog radio

Ocean waves carry energy by making the water move up and down. In much the same way, radio waves carry energy as an invisible, up-and-down movement of electricity and magnetism. This carries program signals from huge transmitter antennas, which are connected to the radio station, to the smaller antenna on your radio set. A program is transmitted by adding it to a radio wave called a carrier. This process is called modulation. Sometimes a radio program is added to the carrier in such a way that the program signal causes fluctuations in the carrier's frequency. This is called frequency modulation (FM). Another way of sending a radio signal is to make the peaks of the carrier wave bigger or smaller. Since the size of a wave is called its amplitude, this process is known as amplitude modulation (AM). Frequency modulation is how FM radio is broadcast; amplitude modulation is the technique used by AM radio stations.

What is the difference between AM and FM?

An example makes this clearer. Suppose I am on a rowboat in the ocean pretending to be a radio transmitter and you are on the shore pretending to be a radio receiver. Let us say I want to send a distress signal to you. I could rock the boat up and down quickly in the water to send big waves to you. If there are already waves traveling past my boat, from the distant ocean to the shore, my movements are going to make those existing waves much bigger. In other words, I will be using the waves passing by as a carrier to send my signal and, because I will be changing the height of the waves, I will be transmitting my signal by amplitude modulation. Alternatively, instead of moving my boat up and down, I could put my hand in the water and move it quickly back and forth. Now I will make the waves travel more quickly—increasing their frequency. Therefore, in this case, my signal will travel to you by frequency modulation.

Sending information by changing the shapes of waves is an example of an analog process. This means the information you are trying to send is represented by a direct physical change (the water moving up and down or back and forth more quickly).

The trouble with AM and FM is that the program signal becomes part of the wave that carries it. Therefore, if something happens to the wave en-route, part of the signal is likely to get lost. In addition, if it gets lost, there is no way to get it back again. Imagine I am sending my distress signal from the boat to the shore and a speedboat races in between. The waves it creates will quickly overwhelm the ones I have made and obliterate the message I am trying to send. That is why analog radios can sound crackly, especially if you are listening in a car. Digital radio can help to solve that problem by sending radio broadcasts in a coded, numeric format so that interference doesn't disrupt the signal in the same way.