Amplitude modulation (AM) signals

Question

Which signal produces a frequency spectrum that could be compared to a complex signal, sine wave or square wave? Why?

Answer 1

Whether it is a sinusoid signal (single tone), or a square signal (multiple tones), they all are composed of sinusoids, the fundamental building block of all signals. The answer to your question needs a detailed discussion of Quadrature (Complex) Signals. I refer you to Chapter 8 of the book 'Understanding Digital Signal Processing' by Richard Lyons, 3ed.

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