Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Radio, in which parameter is the information?

  1. Mar 19, 2006 #1
    When I listen to radio, then I know that the radio gets the information from electromagnetic radio waves. But in which parameter is the information of the song/news/output/whatever included?

    It can't be amplitude, since amplitude decreases with distance of obstruction, and the data most people receive is relatively identical.

    it can't be frequency/wavelength, since every channel has a constant frequency assigned to.
     
  2. jcsd
  3. Mar 19, 2006 #2
  4. Mar 20, 2006 #3

    jtbell

    User Avatar

    Staff: Mentor

    In the USA, each FM channel actually spans a frequency range of 0.2 MHz. For example, a station that broadcasts at 90.1 MHz actually uses frequencies between 90.0 and 90.2 MHz.

    http://www.fcc.gov/mb/audio/bickel/oddno.html

    The diagram on that page has a typographical error. FM Channel 202 should be labeled as 88.3 MHz.
     
    Last edited: Mar 20, 2006
  5. Mar 20, 2006 #4

    DaveC426913

    User Avatar
    Gold Member

    AM = amplitude modulation
    FM = frequency modulation

    Remember that the radio freq is a carrier wave. This means that the (AM)680kHz wave or (FM)107.1 MHz wave is modulated to provide a much lower normal humans range signal riding on top.

    FM = the frequency of the carrier is modulated to carry sounds in the normal human range
    AM = the amplitude of the carrier is modulated to carry sounds in the normal human range
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Radio, in which parameter is the information?
  1. Which is it? (Replies: 4)

  2. Radio isotopes (Replies: 2)

  3. Radio waves (Replies: 4)

Loading...