Telecommunications Flashcards
nature and scope of telecommunications engineering
Engineers working in the telecommunications field may be required to:
-analyse customer needs, test equipment for faults, repair faulty equipment, evaluate equipment and systems, advise on building material and costs, build and test prototypes of new equipment, research information and solve telecommunications related problems, locate and organise telecommunications equipment to be imported from overseas, supervise installation and use of telecommunications equipment, provide training for company staff once new equipment has been installed. design, provide and keep up-to-date systems and make sure new equipment meets government regulations
health and safety issues
some concerns have been raised regarding the potential health effects such exposure might incur to both regular phone users and those servicing the tower.
training for the profession
Predominately electrical engineering, but use skills from maths, physics, computer science, software engineering, systems analysis, metallurgy and materials engineering, marketing and design..
4 years at university, offered at TAFE and uni, experience required before full membership of Australian Institute of Engineering may be granted,
teamwork, project management, computer literacy and oral/written communication.
career prospects
limitless career options for appropriately trained and motivated people. public and private industries, broadcasting enterprises and research institutions.
relations with the community
bring increased services to community.
complaints about telephone infrastructure and fibre optics cable roll outs. potential health effects living near microwave towers and high-tension power lines.
technologies unique to the profession
optical fibre used for increasing efficiency and capacity within telecommunications.
laser technology
satellite systems
internet
legal and ethical implications
privacy - messages take take different routes, making them susceptible to the message being intercepted and examined by other people. spam and junk mail, distribute message at lower cost. storage of personal information on databases can allow the electronic tracking of spending habits, personal and financial details. sophistication and reduced cost of modern equipment raises the potential for others to track and monitor our conversations, likes and dislikes, friends and acquaintances etc without our consent
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engineers as managers
plan infrastructure, development and improvement. system implementation requires careful planning in the early stages to consider not only current technology and needs but also room for future modifications, upgrades and expansion in capacity
current applications and innovations
allow people to work from a fixed setting, video conferencing and the transfer of data between centres. allow specialist doctors to access real-time data from paramedics in the field or home monitoring equipment. Digital Xrays can be transferred.
3D and HD television, video telephones, GPS, smart refrigerators that can create a shopping list
historical development within the telecommunications industry
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the effect of telecommunications on people’s lives
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materials and techniques used over time and development of cathode ray television including B/W and colour
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specialised testing - voltage, current, insulation
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specialised testing - signal strength and testing
A voltmeter is placed parallel across the position to be checked and the value read.
copper and its alloys in telecommunications including copper beryllium, copper zinc, electrolytic tough pitched copper - structure/property relationship and their application
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semiconductors such as transistors, zener diodes, light emitting diodes and laser diodes - uses in telecommunications
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polymers - insulation materials
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fibre optics - types and applications
consist of glass fibres, through which information is passed using light and the principle of total internal reflection.
properties: light weight, high flexibility, low dispersion, low attenuation, high bandwidth, resistance to kinks, unaffected by power surges, unaffected by electromagnetic interference. difficult to tap, leading to increased security.
fibre optics - materials
the double crucible method - uses two crucibles, one inside the other, both of which empty through a common orifice. the emerging fibre contains a core from the inner crucible with a sheath originating from the outer crucible
modified chemical vapour deposition (MCVD) - uses a silica base or preform onto which a gas mixture is deposited. the mixture used determines the refractive index of the glass. the gases are condensed onto either the outside surface of a rod or the inside of a tubular preform to form the core. the preform is then heated in an oven and glass fibre drawn from it down to a desired thickness.
telecommunications including - analogue and digital systems
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telecommunications including - modulation and demodulation
The successful transmission of information requires a carrier. modern communication uses electromagnetic radiation as the carrier. In order to add information to electromagnetic radiation, however, we need to modify or modulate the radiation in a controlled manner.
Modulation can be achieved by the variation of some aspect of the electromagnetic signal. The parameters available for control are:
- frequency of radiation
- amplitude or power level
- phase of the waveform relative to a standard.
Within electrical systems, noise can include interference from other electromagnetic signals, from other transmissions or equipment with electromagnetic fields, excessive heat build up in circuits and electrical storms.
Transmission is limited by the amount of noise in the system and depends on:
- bandwidth
- temperature
- type of modulation
telecommunications including - radio transmission (AM, FM, digital)
AM - in amplitude modulation the intelligence signal is modified by being combined with a sinusoidal waveform of constant amplitude and frequency known as the carrier. In essence, the intelligence and carrier signals are multiplied together to form a new signal. “noise” reduces the sound quality.
Advantages- Demodulation can be done using few components and a circuit. The receiver used for AM is very cheap.
Disadvantages - It requires a very high bandwidth that is equivalent to that of the highest audio frequency. Noise interference is highly noticeable.
Used in some radio stations and visual signal for TV
FM - The FM system modulates the frequency of the carrier wave and not the amplitude. Noise does not affect FM as much as it does AM.
Advantages - less interference and noise, less power consumption compared to AM, adjacent FM channels are separated by guard bands.
Disadvantages - Equipment cost is higher. Has a large bandwidth, the receiving are of FM signal is small, the antennas for FM systems should be kept close for better communication.
Received by aerial ->amplified->detected->demodulated to remove the carrier frequency->amplified and sent to the loudspeaker.
telecommunications including - digital television transmission and display such as plasma, LED, LCD, 3D
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telecommunications including - telephony: fixed and mobile
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