We have argued that the crystal is the metronome but you know that.
Use the RO variable oscillating current flow only as a "reference" (like a teacher or music conductor) in a PLL circuit. Then take the low frequency current from the fixed external crystal oscillator put it into the PLL, pump it up and let it run the processor at the same time letting the high speed RO current line control the pumped up crystal oscillator current. Doing all this in the PLL circuit.
This reference crystal is a metronomeand they
compare it to their muchfaster, extremely
faster ring oscillator that is flying aroundat
a much faster frequency, and they have to do
that, they have to use that, because they can't
get a clock that's fast enough to do what they
want otherwise.
Andthe fact of the matter is, as a
result of the laws of physics, if you have your
ring oscillator, all of the transistors, all of
the inverters of your ring oscillator on the
samepiece of silicon, integrated circuit as a
CPU, as a matter of the laws of physics, they
will be affected similarly with respect to
temperature and voltage changes and even
semiconductor manufacturing variations at the
fab, even if you have a PLL, because that PLL
doesn't lock it in to a specific frequency,
it's within a range.
