I am going to demonstrate something called

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I am going to demonstrate something called
By Ma Yiu Fung 6A(19)
TELECOM
TELECOMMUNICATION
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Purposes

• 1.Makes communication effective and convenient
• 2.Provides invaluable capabilities to the
• commercial field
• 3.Saves human resources
• 4.Save time

Actually,there are more advantages by using
telecom,but what does telecommunication mean??
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What is telecommunication?

• Telecommunication can be expressed by the science
  and technology of communication at a distance by
  electronic transmission of impulses, as by

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I wonder what are the modes of these
transmissions.
telegraph
microwave (radio)
Others(icq,e-mail,etc)
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1.Direct mode transmission

• Twisted wires
• Coaxial cable

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Twisted-wire pair
-Susceptible to local electrical noises
-Cheapest transmission medium
- It us typically used for telephone lines.
- Telephone lines are designed for voice
communication while computers use a digital
signal.
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Coaxial cable
- has greater capacity to transmit data.
- commonly used for LAN applications
-More reliable as it is better insulated
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There are some other examples.

• Traditional Telephone Cable
• POST OFFICE TELECOMMUNICATIONS SPECIFICATION TO
  CW 1293
• POST OFFICE TELECOMMUNICATIONS SPECIFICATION TO
  CW 1308C

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Is using these cables a effective communication ?
Soany other cable?
I dont think so
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• 3. Optical fibre

• Very expensive transmission medium
• Not subject to electrical disturbance
• Suited for long distances communication in high
  data rate

- Light passes along the coated fine cylindrical
glass tubing by reflection
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Optical fibre
- Both voice and data signals can be carried on
the same line.
Its really great!!!!
- data can travel very fast.
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2.Broadcast mode transmission
Satellite transmission
Ground station receive the data and beam to the
satellite by microwave
Satellite will re-transmit data to another ground
station
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Is these all the technology for telecommunication?
Three satellites can cover the Earth effectively
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Nowadays, there are many new technology such as

• Infra-red
• Bluetooth
• Wave 1.Microwave
• 2.Novel Millimeter-Wave Receiving
  Technology
• Patch Antenna with L-shaped Probe
• Others

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Infra-Red

• Infra Red--Light that is so red humans cannot see
  it. A band of the electromagnetic spectrum
  between the visible and the microwave.
• Products such as optical mouse, mobiles, remote
  control are using Infra-red.

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Bluetooth

• The bluetooth wireless technology makes it
  possible to connect and compatible and stationary
  communications device without using cable. the
  technology is based on a radio link that offer
  fast and reliable transmission of voice and data.

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• Many mobiles, cameras and components of computer
  make good use of bluetooth.

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• But, People prefer Bluetooth rather than
  Infra-Red.

• Because information and files maybe stolen by the
  others in infra-red transmission.
• Besides, Bluetooth not only can prevent from
  being stolen information, the transmission is
  even faster than the Infra-Red one.
• Also, the range of transmission of infra-red is
  much less than the bluetooth one.

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Also
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Value proposition of Bluetooth
Data access point
Internet access
Cable replacement
Less expensive than cables such as optical fibre
Ad hoc networking
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Some applications for the society

• Besides these benefits, bluetooth also works in
  hosiptal, as it has less chance to affect the
  operations.

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Business Applications
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Novel Millimeter-Wave Receiving Technology

• Wireless communications using millimeter-wave can
  provide wide band (in GHz) for high data rate and
  large subscribers. The millimeter-wave receiving
  technology developed by CityU employs two novel
  inventions the 4th sub-harmonically pumped
  millimeter-wave PBG mixer and the
  sub-harmonically injecting locked PLL oscillator
  for down converter. The down converter has ultra
  low conversion loss (6 dB) which is as good as
  the conventional fundamentally pumped mixer, but
  at a much lower cost.

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Patch Antenna with L-shaped Probe
In this communication and information era, high
speed and wide bandwidth wireless communications
system are highly demanded. Undoubtedly, antennas
play a crucial role in the systems. A novel
feeding technique by using L-shaped probe was
invented. Through this technique, the inherited
narrow bandwidth problem of conventional planar
antenna can be solved. As a result, wide band
antennas that can be operated at GSM, PCS, CDMA,
UMTS, or multibands with specific characteristics
such as dual-polarized radiation have been
designed. Due to low fabrication cost and simple
structure, the antennas have very good market
value. A company has been set up in Yantai,
Shandong of PRC to manufacture and market the
antennas.
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Reference
Thanks for your attention!!

• http//www.hotsync.com.hk/products.htm
• http//www.act-tel.com.tw/_pg/products/productItem
  .asp?productKey39UnitsManageNameIP20Phone
• http//zhongyan.en.alibaba.com/group/0.html
• http//www.keystonecable.com/proprof01_01cont03.ht
  m
• http//www.telelink.com.hk/
• http//www.111222333.com/SearchResult.asp?action_b
  uttoncategorycategoryTelecommunications