Used to StackOverflow, this is my first question here. So please bear with me if the question is too simple and obvious to you as I am not good in Electrical Engineering stuff. I really need to understand this as part of a Computer Networking course:
I read that a composite signal can be thought of as a combination of simple sine waves and multiplexing is a method by which multiple analog message signals or digital data streams are combined into one signal over a shared medium. Now here are my confusions arising from this:
a) Can multiple composite signals be multiplexed, transmitted and then demultiplexed into the original composite signals? Or only non-composite, single-frequency signals be multiplexed and then demultiplexed into original non-composite signals? If the former is true, does demultiplexing entail separating the constituent frequencies of individual composite signals and then combining them to get the original composite signals? Is that a complex procedure?
b) Can a multiplexed signal be called a composite signal, more so if it is composed of separate composite signals? Can it certainly be considered a composite signal if it is composed of non-composite, single-frequency and separate signals?
c) Does data communication mostly involve composite signals (with many constituent frequencies), or are non-composite, single-frequency signals are also used in communication?
Your answers will be helpful.