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Why do we need in-phase & quadrature components of a signal?

  1. Nov 14, 2015 #1
    Why not work with the complete signal, instead of breaking it into in-phase and quadrature components?
  2. jcsd
  3. Nov 14, 2015 #2


    Staff: Mentor

    Usually that is done because you want to work with a lower frequency version of the signal. Either demodulated to baseband or to some Intermediate frequency.
  4. Nov 14, 2015 #3


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    Science Advisor
    Gold Member
    2017 Award

    It is quite possible to deal with the signal as it comes - a variation of Voltage with time. Some processes are just easier to accomplish in the frequency domain and using complex numbers. When I say "easier", that assumes that your a familiar with that stuff. If you aren't then those processes could be pretty hard to comprehend in either time or frequency domains. It gets difficult pretty rapidly. :smile:
    I guess a simple answer is that quadrature components of a signal; are orthogonal to each other and the components can be treated separately and independently. You could, for example, get two AM signals transmitted together on quadrature carriers and then recover them separately. But you would need to keep the quadrature relationship going throughout the process.
  5. Nov 14, 2015 #4
    Thank you...
  6. Nov 14, 2015 #5
    Thank you...
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