Phase shifting and EMF interference

Discussion in 'Wireless & RF Design' started by HellTriX, Aug 15, 2008.

  1. HellTriX

    Thread Starter Active Member

    Apr 11, 2008
    83
    1
    Had a few questions about phase shifting and EMF wave interference.
    This is a subject I'm weak in.

    I would first like to know what happens when two radio waves converge. Like say you have to different (but close) frequencies flying through the air they can interact on an object and cause the object to see a the frequency of the converged waves (doppler shift or something like that). My question is, do the waves ever actually merge to create a new frequency or do they always exist and separate entities?

    My question stems from the interest to transmit a single EMF or multiple ones in different phase shifts and have them interact on some object. This object would need to observe this signal not as multiple waves but as a much higher frequency. So what do I need to know to help me understand what is going on in this scenario?

    Tnx.
    BTW SgtWookie: I got that 4093 oscillator circuit screaming up to 909khz just for fun:D Just don't ask how clean the waveform was :p
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    They stay separate, but can interact within some conditions. Electronics especially sets up those conditions. An AM radio wave modulated with 1Khz is actually 3 frequencies, the carrier wave, the carrier wave - 1Khz, and the carrier wave + 1Khz. The radio hetrodynes these frequencies with a nonlinear device (such as a rectifier diode) to create 1 KHz, the sum and the difference being the output of hetrodyned frequencies. You can even eliminate one of the sidebands and it continues to work just fine. Frequency multiplication, which is what I think you are talking about, is the sum of the two frequencies.

    There is another way that is different, that is to distort the waveform from a sine wave. All repeating waveforms can be described by the base frequency and it's harmonics. The math for this is Fourier Analysis, a form of differential equations. Distort the wave form, create harmonics. It's that simple.
     
  3. HellTriX

    Thread Starter Active Member

    Apr 11, 2008
    83
    1
    So I have read of frequency multiplication specifically related to lasers shooting into a crystal which then creates and oscillator which emits a doubling of frequency.

    Is their any feasible way to multiply frequencies together and have them emit as a combined (single, coherent) wave. Not including the detection of 2 waves and recreation of them electronically.

    Rephrased: Say if you have the circuity to emit 1mhz but your design cannot support 2mhz, but you can generate 1mhz in two more more phases. Is their a way to use antenna, capacitors, or other passive components to merge the two frequencies into one. (I have this image of a like a microwave magnetron or something)
     
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