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radio waves
 

radio waves

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    radio waves radio waves Presentation Transcript

    • The use of radio waves and signals beyond radio broadcasting By Chadney Bigby
    • What are radio waves
      • Radio waves are a type of electromagnetic radiation.
      • They transmit through free space by modulation of electromagnetic waves with frequencies below those of light.
      • The frequencies can range from 300GHz to as low as 3kHz.
      • They travel at the speed of light, naturally occurring radio waves are made by lightning.
    • Radio Waves
      • The two most known radio waves are AM (Amplitude Modulation) and FM (Frequency Modulated.)
      • Depending on the information that is being sent AM works by varying the strength of the of the transmitted signal.
      • In telecommunications and signal processing FM varies its frequency to send information over a carrier wave.
    • Radio waves in medicine
      • Radio waves have been used in medical treatments for many years.
      • It is normally used for minimally invasive surgeries like the treatment of sleep apnea.
      • The waves are also used as Magnetic resonance imaging (MRI) uses radio frequencies to produce images of the human body.
    • Radio telescopes
      • As radio waves are larger that optical waves, radio telescopes work in a different way to visual telescopes.
      • Radio telescopes focus on a point by using conducting metal that reflects radio waves.
      • To make images of comparable clarity the radio telescope must physically be larger than an optical telescope.
    • Radio waves in technology
      • Early uses in radio waves were used for sending Morse code between ships and land
      • In modern times radio takes up many forms in everyday live.
      • They are used in daily devices such as mobile phones, wireless networks, radio broadcasting and television
    • Radio in telephony
      • Mobile phones work by transmitting to local cell sites (receiver) that connects to a public switched telephone network.
      • 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.
      • Phones originally used FM but the have now changed and use digital modulation.
    • Radio waves in Video
      • Television sends the picture as am an the sound as either AM or FM.
      • Analogue television uses vestigial side-band to reduce the bandwidth required
      • 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
    • Wi Fi
      • 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.
      • This happens because a wireless transmitter sends and recirves from the internet through the broadband connection.
      • The information is converted into radio waves by the transmitter and then sends it.
    • Bibliography
      • http://en.wikipedia.org/wiki/Radio
      • http://people.csail.mit.edu/rudolph/Teaching/L2-2.pdf
      • http://en.wikipedia.org/wiki/Amplitude_modulation
      • http://en.wikipedia.org/wiki/Frequency_modulation
      • http://en.wikipedia.org/wiki/Vestigial_sideband#Vestigial_sideband_.28VSB.29
      • http://www.bbc.co.uk/webwise/guides/about-wifi