Help Understanding Mixing Circuits?

Discussion in 'General Electronics Chat' started by sjgallagher2, Oct 1, 2013.

  1. sjgallagher2

    Thread Starter Member

    Feb 6, 2013
    This has been driving me crazy.
    I'm learning about communications circuits, more specifically mixers and modulators. It's been a bumpy road, since I'm having a lot of trouble grasping some of the core concepts, such as sideband energy. But now I would just like to gain some understanding about nonlinear components' role in mixer circuits. All the sources I've seen so far state simply that 'nonlinear components create sum and difference frequencies whenever two signals are applied to them.' But that's not much help, because:
    1) Why is it only nonlinear components? And
    2) How come a component, that (the way I understand it) has as nonlinear a transfer function as a broad exponential function or as sharp as a switch, cause the same reaction every time when two signals are applied?
    3) Is there a mathematical way to represent what's going on?
    4) What's the simplest circuit that uses this concept? (No filtering)
    5) How did people find this fact out?
    6) What experiments can I do to help me understand what's going on from start to finish in the mixing process?

    Any answers to any of these questions is much appreciated, I know some answers must be somewhat involved, so even a push in the right direction is highly appreciated. ~Sam Gallagher