- •29 Word study Verbs and related nouns
- •34 Language study Describing a process
- •3 6 Writing Describing a process
- •Tuning-in
- •66 Writing 2 Ordering components
- •74 Tuning-in
- •81 Listening
- •82 Language study Would
- •In the future, electronics are likely to become even more common in the home as multimedia entertainment systems and computer-controlled robots are developed.
- •Rf carrier
- •Introduction to Electronic Systems
- •16 Weeks X 2 VI hours
- •When is the lunch break?
- •10 These tolerances may seem to reflect poor manufacture but in most circuits they are, in fact, quite satisfactory. Relaxing the tolerance enables the makerto sell them more cheaply.
- •X varactor diode
- •Identify each of the following diodes:
- •10 The first stage consists of a transformer which steps down the voltage of the ac mains (see Fig. 2).
- •Smoothed dc input
- •15 Common is reverb (reverberation) which can make the music sound as if it was recorded in a very large building or a very small room.
- •Making a recording Places People Equipment
- •4 How is mixing down like developing and printing a photograph?
- •In this text which are additional to those given on the tape.
- •3 You must always keep an eye on the recording level.
- •1 A photodiode picks up rays from the remote control.
- •Ir diode
- •2 How many detection devices does it show? Name them.
- •4 If a burglar walks in front of a motion sensor,
- •7 A magnet on the moving part trips a switch if
- •Sensing device Used to detect
- •9V battery
- •In a frequency-modulated (fm) wave, the audio signal is combined with the rf carrier wave to vary the frequency of the carrier (see Fig. 2).
- •Af power amplifier
- •Via di Pietra Papa 00146 Roma
- •25 Die away naturally. As it dies, the current in the object reactivates the search coil. This voltage is then amplified to indicate with a sound or a flashing light that an object has been found.
- •4 The magnetic field a voltage in the search coil.
- •5 Noise is also by the low-frequency mains supply.
- •In left
- •In right о г
- •Interviewer: a test engineer. What would that involve?
- •I Is there any other kind of work you! enjoy?
- •15 Instead of recording the sound waves continuously, a drum з
- •4 These are converted to electrical signals by (use) a microphone.
- •15 Vinyl records are eliminated such as 'crackle' caused by dust and static, and 'jumping', due to scratches on the recording surface.
- •8 What might be the effect of so many people having cd players?
- •1 Unlike lPs, cDs use a digital recording system.
- •7 The electron gun in a crt a stream of electrons.
- •20 With an oscilloscope so that a visual display of the waveform can be seen.
- •45 Electrons.
- •Video cassette recorder
- •Italics from the text below. One has been done for you.
- •Vhs video-recorder mechanism
- •15 The number of iCs used in a computer, I.E. The chip count, can be reduced by connecting nand gates together to form other types of gates (see Fig. 3).
- •Integration as shown in Table 1. The 1с shown in Fig. 2 is an ssi 20 device but microprocessors used in computers are vlsi or slsi devices.
- •Input impedance low high
- •Instead of using the complicated springs, cogs, and wheels of a mechanical watch, the digital watch uses a vibrating crystal to keep time. It is accurate to one second in 10 years.
- •Vibrating crystal
- •15 Each one-second pulse triggers the microchip to send signals to the digital display to advance the numerals by one second.
- •Xdiaphragm
- •65 System.
- •1 Engineers developed optical fibre cables in the 1980s.
- •2 What is the purpose of the dielectric material in coaxial cable?
- •Insulator (e.G. Polyethylene) sheath
- •Insulator (e.G. Polyethylene) covering wire
- •25 Microwaves can be guided along rectangular copper ducts by a series of reflections from the inner walls (see Fig. 4).
- •If you make a mistake when keying in a number and you want to delete the last digit:
- •If you hold down clr,the whole numberwill be deleted and the p3 will go back to standby.
- •3 What is the difference between a mobile phone and a cellphone?
- •20 Telephone calls at the same time. To achieve this, each
- •30 Compromise between the number of frequency channels available in each cell and the interference between communications in different cells.
- •40 Calls from other cellphones and fixed telephones throughout the whole telephone system (see Fig. 2).
- •50 Call, the 8kHz signal is discontinued and the speech channel is enabled.
- •8 The signal indicates a suitable frequency channel for the call.
- •5 Converts the binary data into digital information (lines 21-22)
- •International international
- •40 As ordering goods and controlling bank accounts.
- •1 Avionics
- •2 Computing
- •3 Defence
- •1991-Present
- •1990-1991 Summer 1989
- •1 A technician with experience in servicing hospital equipment.
- •4900 University Avenue
- •If you would like to hear about outstanding opportunities in Europe to work in the expanding area of personal communication systems, write to:
- •If you can fill one of these vacancies, contact us at once.
- •I'm interested. I have the following training/ experience:
- •If a target is hit. .
- •Input signal
- •1 Manufacturing
- •2 Planning
- •3 Installation
- •4 Commissioning
- •If a target is hit. .
- •5 Maintenance
- •6 Sales
- •8 Research and Development
- •30 Large companies run their own r&d departments. Exciting
- •Induced in an inductor in opposition to the
- •Video image of the internal organs of a
- •2 [13] One side (left or right) of a stereo
- •In one unit and sharing a common
- •Voltage produced by an electrical source
- •241 Solid cylinder of metal oxide insulating
- •Video picture flip-flop /'flip йар/ [24] digital electronic
- •Instrument used for detecting pulses and
- •1 Or 0, high or low) long wave /'log weiv/ [10] range of radio
- •Voltage ac electricity supply maintain /mem'tem/ [22, 29] keep in good
- •Integrated circuit on one piece of silicon microcomputer/,maikraukam'pju:ta(r)/
- •Instrument for measuring various electrical quantities including voltage, current and resistance
- •Inputs are high natural frequency /.Naetjaral 'fri:kwansi/
- •Voltage ionizes the neon gas inside network /'netw3:k/ [26] system of
- •Interconnected devices network manager /,netw3:k 'тгепк1зэ(г)/
- •Interconnected telephone lines for use by
- •In a public telephone network which
- •Voltage which causes a component to pass
- •Various signals used in the test and
- •Integration: between 104 and 10s active
- •Voltage level from varying stable /'steibl/ [24] in a balanced state stage /steid3/ [5] circuit block: section of
- •In a circuit suppress /sa'pres/ [18] prevent a signal
- •Iks,tjemd3/ [28] switching centre for
- •Video signal teletype terminal /'telitaip ,t3:minal/ [28]
- •Images over long distances television receiver Ле1шзп n,si:v9(r)/
- •Isolating an ac supply voltage transistor /traen'zistsir)/ [1]
- •28] Cable or duct for guiding signals
- •Variable capacitor or resistor for making
- •V/VI:/[4, 11] volt
- •Vacuum tube /'vaekjuim tju:b/ [1 ]
- •Vdu /VI: di: 'ju:/ [28] visual (or video)
- •Video screen vdu terminal /VI: di: 'ju: ,t3:min3l/ [28]
- •Video recorders
- •Video-conferencing
- •Voltmeter I
5 Converts the binary data into digital information (lines 21-22)
The first machine transmits these tones (lines 25-26)
It sends a signal (in binary code) (lines 2 8-29)
If the line is noisy (lines 35-36)
Language Study Reduced relative clauses
One way of adding extra information to an explanation, or any other text, is to use relative clauses. For example:
The thermal head is a mechanism.
The head contains a line of dots.
1 +2 The thermal head is a mechanism which contains a line of dots. We can make this sentence shorter by omitting which and using an -ing clause: The thermal head is a mechanism containing a line of dots.
Study this example:
The microprocessor converts the information into signals.
The signals are called analogue tones.
The signals are suitable for telephone transmission.
1 +2+3 The microprocessor converts the information into signals, which are called analogue tones, which are suitable for telephone transmission.
We can make this sentence shorter by omitting which + to be:
The microprocessor converts the information into signals, called analogue tones, suitable for telephone transmission.
Task 7
Shorten this summary of the technical reading passage in Unit 26, pages 144-6, by reducing the relative clauses where possible.
Transmission lines
The lines which connect telephones within a building are the simplest type of transmission line, which consists of parallel wires. Those which link telephones to a local exchange may be twisted pairs, although these are being replaced. Coaxial cable, which is formed 5 from a copper core which is surrounded by a copper braid, is used to carry a large number of signals over long distances. The cables which provide connections between telephone exchanges are often coaxial. Waveguides, which are made of copper, are used to carry microwave signals between dish aerials and receivers. They are suitable for 10 frequencies which are between 1GHz and 300GHz. Optical fibres, which are made from very pure silica fibre, are the form of transmission line which is most often used these days.
Word study Short forms
Some technical words have common short forms. In some cases the short form is used much more frequently than the full form. For example:
Full form Short form
a facsimile message a fax
Task 8 What are the short forms for these terms?
amplifier
video recorder
television
potentiometer
coaxial cable
Task 9 What terms are represented by these short forms?
puff
phones
mike
CRT
phone
Writing Describing transmission processes
Task 10 Look at the flowcharts on the following page.
Study Flowchart 1, which describes in note form what happens when a document is fed into a fax machine.
Complete Flowchart 2 to describe how the data is received by the receiving machine. Use the diagram on page 153 and Texts 1 and 2 (pages 154 and 155) to help you.
Flowchart 1
Sending
Flowchart 2
Receiving
1 Document fed into machine. |
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1 |
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r . _ |
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2 Passes over fluorescent tube. |
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2 |
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3 Image reflected to a lens. |
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3 |
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r |
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r |
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4 Lens passes image to microprocessor. |
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4 |
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1 i |
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r |
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5 Microproces. image into sc horizontal lii |
юг 1 breaks ;ries of les. |
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5 |
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*
6 Microprocessor 2 converts each line into series of binary-coded dots.
t
7 Dots converted into digital information.
1
8 Modem converts digital information into analogue tones for transmission.
Task 11 Use the information contained in both flowcharts to write your own
description of how documents are sent by fax.
Technical reading Communication services Task 12 Read the text and then match these services with the given types of signal.
|
Communications service |
|
Type of signal transmitted |
1 |
telephone |
a |
high-quality text, graphics |
2 |
teletex |
|
characters |
3 |
viewdata |
b |
video,speech |
4 |
radiopaging |
с |
simple text, punctuation |
5 |
fax |
d |
messages |
6 |
videophone |
e |
radio signal, beep |
7 |
f |
text, graphics, photographic images |
|
8 |
teletext |
g |
speech |
9 |
telex |
h |
interactive information, e.g. travel, |
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shopping, banking |
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i |
general information, e.g. news, |
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sports results |
Communications services
Telephones, connected by a network of cables, are commonly used for the two-way transmission of speech. The signals are switched from one line to another at switching centres known as telephone exchanges. Lines in a small area are switched by local exchanges, 5 local exchanges are connected through trunk exchanges, and trunk exchanges are connected to other countries by international exchanges. Such a system is called a Public Switching Telephone Network (PSTN) (see Fig. 1).