radio waves


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radio waves

  1. 1. The use of radio waves and signals beyond radio broadcasting By Chadney Bigby
  2. 2. What are radio waves <ul><li>Radio waves are a type of electromagnetic radiation.
  3. 3. They transmit through free space by modulation of electromagnetic waves with frequencies below those of light.
  4. 4. The frequencies can range from 300GHz to as low as 3kHz.
  5. 5. They travel at the speed of light, naturally occurring radio waves are made by lightning. </li></ul>
  6. 6. Radio Waves <ul><li>The two most known radio waves are AM (Amplitude Modulation) and FM (Frequency Modulated.)
  7. 7. Depending on the information that is being sent AM works by varying the strength of the of the transmitted signal.
  8. 8. In telecommunications and signal processing FM varies its frequency to send information over a carrier wave. </li></ul>
  9. 9. Radio waves in medicine <ul><li>Radio waves have been used in medical treatments for many years.
  10. 10. It is normally used for minimally invasive surgeries like the treatment of sleep apnea.
  11. 11. The waves are also used as Magnetic resonance imaging (MRI) uses radio frequencies to produce images of the human body. </li></ul>
  12. 12. Radio telescopes <ul><li>As radio waves are larger that optical waves, radio telescopes work in a different way to visual telescopes.
  13. 13. Radio telescopes focus on a point by using conducting metal that reflects radio waves.
  14. 14. To make images of comparable clarity the radio telescope must physically be larger than an optical telescope. </li></ul>
  15. 15. Radio waves in technology <ul><li>Early uses in radio waves were used for sending Morse code between ships and land
  16. 16. In modern times radio takes up many forms in everyday live.
  17. 17. They are used in daily devices such as mobile phones, wireless networks, radio broadcasting and television </li></ul>
  18. 18. Radio in telephony <ul><li>Mobile phones work by transmitting to local cell sites (receiver) that connects to a public switched telephone network.
  19. 19. When a mobile is near the edge of a cell and moves into another cell's coverage area it will switch cell sites to continue the call.
  20. 20. Phones originally used FM but the have now changed and use digital modulation. </li></ul>
  21. 21. Radio waves in Video <ul><li>Television sends the picture as am an the sound as either AM or FM.
  22. 22. Analogue television uses vestigial side-band to reduce the bandwidth required
  23. 23. Vestigial side-band is a method used in analogue video transmitted in AM due to large bandwidth. It is a side-band that has been partially been cut off or suppressed </li></ul>
  24. 24. Wi Fi <ul><li>Wi-fi (wireless networking) in the home or office creates a network which is a zone where computers and devices can connect to the internet.
  25. 25. This happens because a wireless transmitter sends and recirves from the internet through the broadband connection.
  26. 26. The information is converted into radio waves by the transmitter and then sends it. </li></ul>
  27. 27. Bibliography <ul><li>
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