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How are soundwaves sent via em waves?

  1. Oct 27, 2012 #1
    When the mic hears the noise, it creates an alternating current electrical signal right? So how does that translate to em waves? Is it just that a higher frequency radio wave length would resemble a higher pitch? If so, is it impossible to hear the pitch "produced" by, say, visible light?
     
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  3. Oct 27, 2012 #2

    dlgoff

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    Sound waves in air are longitudinal



    lwav2.gif



    and electromagnetic waves are transverse.



    emwavec.gif
     
  4. Oct 27, 2012 #3

    Integral

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    Read about a Superheterodyne_receiver. BTW this is your everyday radio. It turns RF E&M waves into sound waves. Similar to what you are asking. It is a very similar process in reverse to go the other way.
     
  5. Oct 27, 2012 #4
    It depends on the form of modulation. In amplitude modulation, the EM wave increases and decreases in amplitude, depending on the audio signal. So, when the audio signal reaches a high, the EM wave has a large amplitude. Likewise, when the audio is at its minimum, the amplitude of the wave is small. Frequency modulation works by increasing frequency when the audio signal is at its high, and decreasing frequency when its at its low. Wikipedia has a nice animation of such modulations: http://upload.wikimedia.org/wikipedia/commons/a/a4/Amfm3-en-de.gif
     
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