Am I right about how FM synthesizers work?

[IvarA]

I have been looking into FM Synthesizers, and wonder what is the difference from a FM Synthesizer and a regular VCO where the pitch is modulated by the LFO at very high frequency? I tried this on my analog synthesizer, and the result is somewhat similiar at max LFO frequency. If I could have a faster LFO, maybe I would have a FM synth?

 

[VEBill]

Is this question in the context of musical instruments?

There's only the very faintest clue ("pitch") in your post that this isn't a question related to communications equipment (at least to those of us in that field). As I suspect it is actually about musical instruments, I thought that the subject area should be clarified.