What is 'spectrum' anyway? How can multiple frequencies exist in one signal?

Easy, easy... :slight_smile:

I think it was meant to be a thought-provoking question, but things like that can be a distraction. I think the OP was just trying to wrangle the discussion back on track. No harm, no foul.

The rest of us in this chat room are here voluntarily. If you don't feel like being an unpaid professor, don't. No one's going to fault you. But I appreciate the privilege to get a discussion going on complex topics. Textbooks can't teach us everything, and the many different viewpoints are invaluable.