8 What might be the effect of so many people having cd players?

9 Which audio system does he favour?

10. What's his longterm forecast?

11. What would be the advantage of such a system?

Task 2 \Ш

Here is the completed table of differences from Unit 16. Listen again to the tape. Tick the differences the expert mentions.

		LPs	CDs
1	Recording system	analogue	digital
2	Sound quality	poorer than the original	like the original
3	Access	serial	random
4	Audio pattern	grooves	pits
5	Material	vinyl	perspex
6	Playing mechanism	mechanical	laser
7	Durability	easily damaged	does not deteriorate
8	Size	12 inches	12cm
9	Playing time	45 minutes	74 minutes

Language Study Comparison and contrast, 2

In Unit 2, we studied some ways of describing similarities and differences in English. In this unit we will examine some other ways to describe differences: to make contrasts.

On the tape the expert contrasted:

1. LPs and CDs

2. analogue and digital recording

3. CDs and newer systems

Here are some of the things he said:

They (CDs) use laser light rather than a needle. LPs are analogue recordings while CDs are digital.

It (an analogue signal) can have any value... but in digital the signal is either on or off.

You can process a digital signal with greater accuracy than a constantly varying signal.

Here are some other expressions used to make contrasts:

differ from is / are different from in contrast to whereas unlike

Task 3 Look back at the table of differences in Task 2. Contrast LPs and CDs for each

point in the table. Use the expressions from the examples listed above. For example:

1 Unlike lPs, cDs use a digital recording system.

Graphs

Reading Understanding graphs

In electronics, graphs are a common way of giving information. They allow a great deal of data to be presented easily in visual form. Mostly this information is technical, but we start with a non-technical example.

Task 1 This graph shows the sales of singles in the UK over a seven-year period some

time ago. This was a period of considerable change in people's choice of format when buying recorded music.

United Kingdom

millions 100-

80-

The figures include 7" and 12" vinyl singles as well as CD and cassette singles.

Singles

60

40

20

0_| __) 1 1 1 | 1 1

1983 1984 1985 1986 1987 1988 1989 1990

Write a sentence to describe sales for these periods:

1. 1983-1984

2. 1986-1988

3. 1988-1989

Language Study Describing graphs

Look at the period 1983-1984 on the graph. We can describe sales of singles in two ways:

1. Sales of singles rose.

2. There was a rise in the sales of singles.

We can make our description more accurate like this:

3. Sales of singles rose slightly.

4. There was a slight rise in the sales of singles.

Study this table of verbs and related nouns of change. The past form of irregular verbs is given in brackets.

Direction

Verb

Noun

Up

Down

Level

climb

go up (went up) increase rise (rose)

decline decrease dip drop fall (fell)

go down (went down)

not change remain constant

increase rise

decline

decrease

dip

drop

fall

no change

These adjectives and adverbs are used to describe the rate of change:

Adjective Adverb

slight slightly

gradual gradually steady steadily steep steeply

sharp sharply

sudden suddenly fast fast

Study this graph, which compares the sales of LPs, cassettes, CDs, and singles over the same seven-year period.

United Kingdom

The figures include 7" and 12" vinyl singles as well as CD and cassette singles.

millions 100

1. Cassettes 1983-1986

2. Cassettes 1989-1990

3. LPs 1983-1988

4. LPs 1988-1990

5. CDs 1983-1984

6. CDs 1984-1985

7. CDs 1985-1986

8. CDs 1986-1990

Task 3 Make comparisons of sales of different products for these periods. For example:

CDs and singles 1986-1988

Sales of CDs rose steeply, but/while sales of singles fell steadily. As sales of CDs rose, sales of singles fell.

1 CDs and LPs 1986-1988

2 CDs and cassettes 1986-1988

3 Singles and CDs 1983-1984

4 Cassettes and LPs 1983-1986

5 Singles and LPs 1989-1990

Task 4 Try to explain the changes on the graph. List your reasons. Then compare your

ideas with this text:

In 1989, sales of compact discs (CDs) exceeded sales of long-play albums (LPs) for the first time. By 1990, CD sales were more than double those of LPs. Cheaper CD players and the introduction of mid-price and budget-price discs have been partly responsible for the 5 increase in CD sales.

Sales of LPs fell by 35 per cent between 1989 and 1990 to less than 25 million, and cassette sales also fell. Despite this, cassettes still accounted for over a third of all items sold. Their continued popularity is partially due to the increase in ownership of personal stereos.

Word Study Common verbs in electronics

Task 5 These verbs are often used in electronics:

conduct emit rectify sample dissipate process record suppress

Fill in the gaps in these sentences with an appropriate verb from the list above. Make sure the verb is in the correct form.

1. Computers data.

2. You can sound on tape or disc.

3. A bridge circuit is used to alternating current to produce direct

current.

4. All metals, and some non-metals such as carbon, electricity.

5. To prevent radio interference, you must any sources of

interference such as car ignition systems.

6 Power transistors heat. Therefore they must be mounted on a

heatsink.