Gary Schafer wrote:
So what you are saying is that the carrier of a modulated signal is
ONLY a frequency domain concept?

Yes.

That would mean that it really does
turn on and off in the time domain at the modulation rate.


"It" only exists in the frequency domain. Talking about the carrier in
the time domain makes no more sense than talking about the sidebands in
the time domain, or the envelope in the frequency domain.

Roy Lewallen, W7EL