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  • Waves and sidebands - AM modulation

    From Vek M@21:1/5 to All on Tue Mar 29 11:18:08 2016
    Hi, I'm trying to understand AM/sidebands intuitively:  https://en.wikipedia.org/wiki/File:Amfm3-en-de.gif 
    (I don't want a mathematical definition - no fourier and sin 
    representation)

    Is the AM wave-output the sum of three vectors - where the two sidebands cancel out and leave only the carrier wave suitably modulated?

    Basically if you look at that diagram (just that red graph) - there are three waves:
    1. is the red line
    2. is the upper envelope and lower envelope

    would it be reasonable to think of the two envelopes as being created by two vectors that cancel out? With the modulated carrier being traced by the third vector? In which case how are the vectors being generated from the signal and carrier?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Vek M@21:1/5 to All on Wed Mar 30 10:34:19 2016
    https://www.youtube.com/watch?v=dNx70orCPnA
    Here's a video of a double slit interference experiment in water with two src. This is similar to AM, as in, we have a carrier and info-signal.

    If you look at the video - the blue water/crests/troughs represent the modulated carrier - our red-line in the wiki-image.

    The upper envelope isn't distinguishable in the YT video, but one could imagine that the envelope was an imaginary surface connecting just the peaks of water which would have varying height.

    The thing is, the YT video is a mechanical wave, whereas AM is an electromagnetic wave - so it's just a bunch of points that could experience some force IF there was a charged particle there. The envelope is therefore like a line of force - invisible to
    the naked eye.

    Is this correct?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)