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Thread: AM?

  1. #1
    simple really

    whats the differnce between AM and FM? is something to do with VHF and UHF

  2. #2

  3. #3
    simle version:

    am: uses a varying amlitude to send the signal
    fm: sends the signal by altering the frequency.

  4. #4

  5. #5

  6. #6

  7. #7
    Guest
    Heres a good analogy...

    A trumpeter can send you a Morse code message in two ways. He can play a note for each dot or dash and vary the loudness, playing a soft note for a dot, and a loud note for a dash. If there is nothing to confuse the sound you could hear it at the other end of a house. Another trumpeter can send a different message by playing a different note and making it louder and softer, and with a wee bit of difficulty you can listen to the right note to make out the message.

    If, however, people are opening and closing doors all the time it becomes very difficult to make out whether any one note is louder or softer and the message, even when it doesnt become inaudible, can get hidden. And it doesnt take a lot of some other noise, such as a violin being played badly, to confuse your ear and make it impossible to pick out the message.

    Alternatively the first trumpeter can use notes of different pitches, one for dot and one for dash. A second trumpeter would have to choose two notes that are both higher up the scale to avoid confusion, but again it would be possible to make out the message despite the second player. Whats more, doors being opened and closed between you and the trumpeter would make the signal hard to hear, but wouldnt hide the actual message short of making it inaudible - the signal is less vulnerable to interference. Also, the violinist would have to work harder to distract the ear from the two-tone warbling of the trumpet.

    Best advice is to stop paying for the kids music lessons and get some peace and quiet!

  8. #8

  9. #9
    Guest
    Erm. Maybe youre right... No Ive just checked... analogy is correct!

  10. #10

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