18/05/2018 1 Teacher Development Program Bringing Schools and Engineering together Year 12 – HSC Telecommunications Presenter - Dr Steve Mitchell Presenter Background • Studied Engineering Science for my HSC! • 7 year Engineering Traineeship after my HSC at A.Goninan & Co Pty Ltd • Completed a Bachelor of Electrical Engineering in 1994 • Worked in various industries with a focus on electronics • Began my PhD part time in 2002 whilst at University of Newcastle (Awarded 2011) • Lectured Electrical engineering Australia + Singapore for several years • Currently the Engineering Manager at Ampcontrol CSM • Also a Conjoint Senior Lecturer at University of Newcastle with a few postgraduate students • Chartered Professional Engineer and a Fellow of Engineers Australia
Transcript
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Teacher Development ProgramBringing Schools and Engineering together
Year 12 – HSC Telecommunications
Presenter - Dr Steve Mitchell
Presenter Background
• Studied Engineering Science for my HSC!
• 7 year Engineering Traineeship after my HSC at A.Goninan & Co Pty Ltd
• Completed a Bachelor of Electrical Engineering in 1994
• Worked in various industries with a focus on electronics
• Began my PhD part time in 2002 whilst at University of Newcastle (Awarded 2011)
• Lectured Electrical engineering Australia + Singapore for several years
• Currently the Engineering Manager at Ampcontrol CSM
• Also a Conjoint Senior Lecturer at University of Newcastle with a few postgraduate students
• Chartered Professional Engineer and a Fellow of Engineers Australia
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Teacher Development ProgramBringing schools and engineering together
• INTRODUCTION – Telecommunications
• The teacher development program provides current, industry related engineering context to the HSC engineering studies course.
• This module is part of a series of 8 modules providing relevant material to the course learning outcomes.
• The presentations provide a forum for teaches to network and interact with Engineers Australia.
• WE AIM TO BE A FACILITATOR IN SUPPORTING YOU.
Teacher Development ProgramBringing schools and engineering together
• Drop box
• We have created an “ENGINEERING STUDIES RESOURCE CENTRE” on Dropbox.
• This can be used by Teachers and Engineers Australia to share and communicate useful resources.
This Module
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This Module
Student Learnings
The Syllabus-HSC Modules
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• “Transmission of signals over a distance for the purpose of communication”
• The word telecommunication is adapted from a compound of the Greek prefix tele, meaning 'far off', and the Latin verb communicare, meaning ‘to share’
• Consists of 3 parts:
– Transmitter
– Medium
– Receiver
Definition of Telecommunication
Telecommunications - History
1785 Coulomb – force between two charges varies with the inverse square of the distance
1820 Ørsted – needle of a compass moves when brought close to a current-carrying wire
1820 Ampere – two parallel current- carrying wires attract or repel
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Telecommunications- History
1831 – Michael Faraday discovers electromagnetic induction
Battery (right) sends an electric current through the small coil (A). When it is moved in or out of the large coil (B), its magnetic field induces a momentary voltage in the coil, which is detected by the galvanometer (G).
Some history…
• 1864 J. Maxwell : Showed that electric and magnetic fields fluctuating together
can propagate through space in waves and that light itself is such a wave
Ref: phys.libretexts.org
Changing EAC Current
Changing B
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Some history…
• 1887 H. Hertz : Demonstrates existence of electromagnetic waves
Some history…
• 1876 Alexander Graham Bell : Awarded the first U.S. patent for the telephone
• 1895 Guglielmo Marconi : First demonstration of long distance radio transmission
• 1907 Commercial transatlantic connections => 100m high antennas
• 1915 Wireless voice transmission New York - San Francisco
• 1928 TV broadcast trials (across Atlantic)
• 1933 Frequency modulation (E. H. Armstrong)
• 1958 A-Netz in Germany, analog mobile, no handover,1971 11000 customers
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Some history…
• 1982 : Start of GSM-specification (Global System for Mobile communication)
• 1990 : Tim Berners-Lee begins writing WorldWideWeb, the first web browser
• 1992 : CSIRO patents key technology needed for Wi-Fi
• Analogue to digital (note the fixed sampling steps)
A bit of theory…
• Digital signals (eg Binary signal measured at fixed sample times)
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A bit of theory…
• Digital logic gates
A bit of theory…
• What about the relationship between time and frequency?
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Telecommunications- Technology
Major components of any communications system
MEDIUM
TRANSMITTED INFORMATION
• It is often convenient or necessary to ‘translate’ the signal from one region in the
frequency domain to another region
• Frequency ‘multiplexing’ => lots of different channels
• Practical antenna => Not too large..
• An auxiliary signal called ‘carrier’ determines the amount of frequency translation
Telecommunications -Technology
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Telecommunications- Technology
Audio Amplifier
ModulatorRF Power Amplifier
Oscillator
Microphone
Antenna
Simple Radio Transmitter
Carrier Frequency
Telecommunications- Technology
Simple Radio Receiver
RF Amplifier
DetectorAudio
Amplifier
SpeakerAntenna
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Telecommunications- Technology
• Amplitude Modulation- Varies the amplitude of the carrier wave (eg: 2HD)
Modulation types
• Frequency Modulation – Varies the frequency of the carrier wave (eg: NewFM)
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Multiplexing (de-Multiplexing)
• Sharing a communications link or medium (ie cable, fibre, wireless band)
• Analogy : Many people in same room trying to talk at once
• How can you hear one conversation when others are talking?
Frequency Division Multiplexing (FDM)
• Modulating each signal with different carrier frequencies (ie Could use AM, FM, ..)
• Analogy : Each person to talk (and listen) at a different ‘pitch’, ie high or low voice
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Time Division Multiplexing (TDM)
• Send “slices” of each information stream consecutively along media channel
• Analogy : Allow each person their own timeslot in which to speak.
• Optical fibres can carry millions of simultaneous ‘conversations’
Time Division Multiplexing
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Space Division Multiplexing (SDM)
• Analogy: Separate people around the room ...
• ‘Cell’ division in mobile telephone network
Wavelength Division Multiplexing (WDM)
• Different colours of light are different wavelengths
• Simply use the different wavelength carriers to transmit different signals
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Applications
• Can use combinations of techniques to hold multiple ‘conversations’:
• Mobile phones use SDM and FDM in adjacent cells
=> i.e. Use different mobile cells + different frequencies
• Optical fibres use TDM and WDM
=> i.e. Use time ‘slices’ + different ‘colours’
Theory to practice…
• Wave speed = Frequency x wavelength
• Wavelength determines size and efficiency of antenna
• 2HD operates at 1143kHz, 262 metres wavelength
• 2NUR operates at 103.9MHz, 2.9 metres wavelength
• Mobile phone at 900MHz, 30cm wavelength
• Antennas smaller than the signal wavelength can be used but will impact on
efficiency and performance.
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Theory to practice…
• What do we have here..?
Telecommunications- Frequency & Wavelength
HF Antenna 1.5 MHz
VHF/UHF Antenna 150/430 MHz
Microwave Antenna1.5 GHz
PCB Antenna5 GHz
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Telecommunications- Societal Influences
Telecommunications- Societal Influence
Moore’s Law
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Telecommunications- Societal Influence
Digital Television:• Signal digitally processed and multiplexed• Australia uses Digital Video Broadcasting (DVB) system • Advantages:
• Lower bandwidth needed• Multiple services in the one frequency band• Can include UHD images and other smart services• Immunity to interference• But susceptible to low signal strength
means used for shorter distances• Glass optical fibers primarily silica• Greater bandwidth• Security• Low attenuation• Immune to electrical interference• Higher tensile strength than copper• Light weight and space saver• But:
• High cost• Repeaters and separate power supplies required
Telecommunications - Materials
Summary
• Engineers Australia is your link with the Engineering Profession / Industry
• These Presentations and forums can provide important networking opportunities with other teaching professionals
• Engineers Australia can assist in providing exciting ways of presenting concepts with real world examples and applications.
• We encourage a link of support with exam assessors
• We emphasise that pathways to engineering exist for all students- Professional, Technical, Trade, VET
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Pathways to Engineering
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