- •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
If you make a mistake when keying in a number and you want to delete the last digit:
■ Press CLR briefly.
If you hold down clr,the whole numberwill be deleted and the p3 will go back to standby.
You can dial a number of up to 32 digits, although only the last sixteen will be shown on the display at any time. To look at the first part of a number longer than sixteen digits:
■ Hold down FCN.
When you have finished the call:
■ Press END.
Reading Recognizing topic, locating detail
When you are reading to find specific details, it is helpful if you can first identify the part of the text most likely to contain the details you want. If you can identify the best area to search, you have a better chance of finding the details quickly.
Task 3 Glance quickly through the text on the following page to identify which
paragraph deals with the following:
a cellphone networks
b how signal levels are controlled
с how the MSC locates a cellphone
d limitations of mobile phone systems
e frequency distribution within cells and clusters
f the development of mobile phones
g how cellphones link with other cellphones and with the telephone system
Task 4 Decide which paragraphs are most likely to contain answers to these questions.
Compare your decisions with your partner, then search for the answers.
Who uses mobile phones?
What does the MSC register of cellphones contain?
3 What is the difference between a mobile phone and a cellphone?
Why is a cellphone called a cellphone?
How large is a cell?
How does the MSC prevent interference due to too strong a signal level?
What's the best number of cells to form a cluster?
When were radiophones developed?
How does an MSC ensure that a cellphone is using the right frequency for a call?
10 What is the MSC permanently connected to?
Cellphones
para
Radiophones, using the VHF band, were developed during the 1
Second World War to provide communications for ships and aeroplanes. At the end of the war they were further developed as mobile phones for use by the emergency services and other 5 services such as taxis.
With mobile phone systems, all communications take place 2
through a central control base station. Mobile units normally do not communicate directly with other mobile units. They send messages to the control base station and the base station controller relays the 10 messages to other mobile units. Although mobile phones can be moved, they must stay within fixed areas. This type of system is limited by the fact that there are not enough VHF frequencies available for large numbers of communications between individual users.
15 The problem of a lack of suitable frequencies can be overcome by з using a cellphone network. A cellular phone (cellphone) is a lightweight, portable radio transceiver which can transmit and receive telephone calls anywhere in the cellular network area. In the network, the same frequencies can be used for many different