5. Communication Techniques

  1. Anil K. Maini and
  2. Varsha Agrawal

Published Online: 4 SEP 2010

DOI: 10.1002/9780470711736.ch5

Satellite Technology, Second Edition, Second Edition

Satellite Technology, Second Edition, Second Edition

How to Cite

Maini, A. K. and Agrawal, V. (2010) Communication Techniques, in Satellite Technology, Second Edition, Second Edition, John Wiley & Sons, Ltd, Chichester, UK. doi: 10.1002/9780470711736.ch5

Author Information

  1. Both of Laser Science and Technology Centre, Defence Research and Development Organization, Ministry of Defence, India

Publication History

  1. Published Online: 4 SEP 2010
  2. Published Print: 15 OCT 2010

ISBN Information

Print ISBN: 9780470660249

Online ISBN: 9780470711736

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Keywords:

  • amplitude modulation (AM);
  • continuous wave communication systems;
  • digital modulation techniques;
  • digital transmission;
  • frequency modulation (FM);
  • pulse communication systems;
  • Shannon-Hartley theorem

Summary

This chapter discusses modulation, demodulation and other relevant techniques. In amplitude modulation (AM), the instantaneous amplitude of the modulated signal varies directly as the instantaneous amplitude of the modulating signal. In frequency modulation (FM), the instantaneous frequency of the modulated signal varies directly as the instantaneous amplitude of the modulating or the base band signal. Pulse communication systems differ from continuous wave communication systems in the sense that the message signal or intelligence to be transmitted is not supplied continuously as in case of AM or FM. Digital transmission of analogue signals has been made possible by sampling the continuous time signal at a certain minimum rate, which is dictated by what is called the sampling theorem. The Shannon-Hartley theorem describes the capacity of a noisy channel. Three well-known digital modulation techniques available for the purpose include: amplitude shift keying (ASK), frequency shift keying (FSK) and phase shift keying (PSK).

Controlled Vocabulary Terms

amplitude modulation; communication systems; CW radar; digital modulation; frequency modulation; information theory