TRANSPONDERS IN SATELLITE - PowerPoint PPT Presentation

Title: TRANSPONDERS IN SATELLITE


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TRANSPONDERS IN SATELLITE
MARUDHAR ENGG. COLLEGE
ASEMINAR REPORTON
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AGENDA

• SATELLITE HISTORY
• TYPES OF SETELLITE AND THEIR USES
• COMPONENTS OF SATELLITE
• TRANSPONDERS
• CLASSIFICATION OF TRANSPONDERS
• APPLICATIONS
• CONCLUSION

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SATELLITE HISTORY
1gt Object which has been placed into orbit by
human endeavour. 2gt World's first artificial
satellite, the Sputnik 1, launched by the Soviet
Union in 1957 3gt It helped to identify the
density of high atmospheric layers and provided
data on radio-signal distribution in the
ionosphere. 4gt Ignited space race between
Soviet Union and the United States. 5gt Sputnik
2 was launched on November 3, 1957 and carried
the first living passenger into orbit, a dog
named Laika. 6gt 6,578 satellites launched into
orbit since 1957.
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NEED OF SATELLITE
1gt Two Stations on Earth want to communicate
through radio broadcast but are too far away to
use conventional means. 2gt Two stations can use
a satellite as a relay station for
communication. 3gt One Earth Station sends a
transmission to the satellite. This is called
a Uplink. 4gt The satellite Transponder converts
the signal and sends it down to the second
earth station. This is called a Downlink.
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TYPES OF SATELLITE AND APPLICATION

• SATELITES BASED UPON ALTITUDE
• LEO (Low Earth Orbit )
• MEO (Medium Earth Orbit )
• GEO (Geostationary Earth Orbit)

• SATELLITES ARE USED FOR A LARGE NUMBER OF
  PURPOSES
• military and civilian Earth observation
  satellites
• communications satellites
• navigation satellites
• weather satellites and
• research satellites.

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BASIC BLOCKS
transponder
BSIC COMMUNICATION SATELLITE COMPONENTS
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TRANSPONDERS
Transponders

• A transmitter-receiver system taken together is
  known as transponder.
• Works LIKE a repeater in the sky.
• Its a series of interconnected units which form
  a single communication channel between receiver
  and transmitter antenna in communication
  satellite.
• Transponder bandwidth depends up on
• a. nature of
  signal.
• b. multiple
  access technique.

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FUNCTIONING OF A TRANSPONDER

• Transponder is also principally used as a
  re-transmitter due to the fact that it receives a
  definite signal from a specific source, then it
  amplifies (magnifies) the signal before sending
  it to a predefined location
• A transponder functions by receiving a signal,
  called an "interrogator" because it is
  effectively "asking" for information, then
  automatically conveying a radio wave at a
  predetermined frequency.
• In order to broadcast a signal on a different
  frequency than the one received, a frequency
  converter is built in.
• By receiving and transmitting on different
  frequencies, the interrogator and transponder
  signals can be detected simultaneously.

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TRANSPONDERS
TYPES OF Transponders

• Basic types of transponders are
• Conventional transparent ( non regenerative
  satellite)
• Processing (regenerative satellite)

TRANSPARENT TRANSPONDER
Tansponder which translates the frequency of the
received signals and amplifies them but applies
no other deliberate processing before
retransmission
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TRANSPONDERS
TYPES OF Transponders

• Only amplification and re-transmission of signal
  is done.

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FEATURES OF TRANSPARENT TRANSPONDER
TYPES OF Transponders

• Its most common satellite transponder type
  used.
• It capture signal from ground stations.
• Capture as little interference and noise.
• Amplify received carriers signal.
• Works as a frequency converter.
• Provide necessary power for transmission.
• Radiate carriers in designated frequency band
  and with assigned polarization.

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TRANSPARENT TRANSPONDER
TYPES OF Transponders
ADVANTAGES relatively simple structure.
reliable system. independent of modulation and
coding multiple purpose (TV, data,
telephony,..)
DISADVANTAGES not only signal is amplified
noise and interference from ground is amplified
as well C/N ratio at earth station receiver is
composed of C/N of uplink and C/N of downlink
longer propagation delay
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TRANSPONDERS
TYPES OF Transponders

• A satellite that provides on-board demodulation
  and remodulation of the information bearing
  signal is referred to as an on-board processing
  (OBP) satellite.
• The OBP satellite, also called a regenerative
  satellite or a smart satellite

REGENERATIVE TRANSPONDER
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TRANSPONDERS
TYPES OF Transponders

• The uplink signal at fup is demodulated to
  baseband, fbaseband.
• The baseband signal is available for processing
  on-board, including reformatting and
  error-correction.
• The baseband information is then remodulated to
  the downlink carrier at fdwn, possibly in a
  different modulation format to the uplink and,
  after final amplification, transmitted to the
  ground.
• The demodulation/remodulation process removes
  uplink noise and interference from the downlink,
  while allowing additional on-board processing to
  be accomplished.

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REGENERATIVE TRANSPONDER
TYPES OF Transponders

• ADVANTAGES
• More signal regeneration so separation of up- and
  downlink
• Because of on-board switching resulting in lower
  complexity and cost of ground stations.
• digital signals easier to handle
• different input/output formats

• DISADVANTAGES
• More complexity on board resulting in
• high reliability required
• potential single-point of failure in the sky

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TRANSPONDER APPLICATIONS
DAILY LIFE APPLICATIONS OF TRANSPONDERS

• Transponders have an abnormally large number of
  applications in various fields
• a) satellite communication
  b) aviation,
• c) marine
  d) automotive,
• e) road
  f) motorsport,
• g) underwater etc.
• They are also used in simple day-to-day tasks
  such as opening a cars door wirelessly.
• The earliest implementation of a transponder was
  aboard an airplane during World War II, as
  component of the Identify Friend or Foe (IFF)
  system. (By responding undisclosed interrogation
  frequencies, the airplane pilots could point out
  to radar operators that they were friendly
  airplanes).
• Transponders are also used to compute distance
  by evaluating the elapsed time between the
  transferring of a signal and acknowledgment of
  the transponders signal. For example, sonar
  transponders are used to locate undersea places,
  estimate depth, and trace locations.

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CONCLUSION
MAY BE USED TRANSPONDERS
After the study its clear that transponders exist
all around us and play a major role in our day to
day life to make living comfortable. Transponders
are effectively utilized in satellite
communication and help in overcoming the
limitations of other communication
medium. TRANSPONDERS ARE HERE TO
REVOLUSIONISE THE PROCESSING OF WIRESS NETWORKS
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Questions???
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REFERENCES

1. http//en.wikipedia.org/wiki/Transponder
2. W.M. Evans, N.G. Davies and W.H. Hawersaat, The
   communications technology satellite (CTS)
   program.
3. http//www.websters-online-dictionary.org/definiti
   ons/Transpondersatellite
4. http//www.freepatentsonline.com/y2005/0068223.htm
   l
5. Communications Satellite Systems An Overview of
   the Technology, R.G. Gould and Y.F. Lum, Editors,
   IEEEPress, New York, 1976, pp. 1318.
6. B. Sklar, Digital Communications Fundamentals
   and Applications, Prentice Hall, Englewood
   Cliffs, NJ, 1988.
7. http//books.google.co.in/books?idWS8uryQFv6ICpgP
   A118lpgPA118dqREGENERATIVETRANSPONDERDEFINITION
   sourcebl
8. L.J. Ippolito, Jr., Radiowave Propagation in
   Satellite Communications, Van Nostrand Reinhold
   Company, NewYork, 1986.