🚀 go-pugleaf

The PLL is good if you have a frequency range where the signal comes
from. However, let me remind you that the circuit block seen by the
input signal (the PHASE DETECTOR) is more or less a COMPARATOR.
Moreover the output signal, which has the same frequency that the
input, has almost allways a "phase shift" from that input that varies
with the distance of the working frequency from the FREE-RUNNING FREQ.
of the PLL. What I mean is that you have always to consider a
COMPARATOR for that matter. If you use one with HISTERESIS
(Scmitt-Trigger type) you will somehow increase the noise rejection.

The complete theory of PLL is somewhat difficult to say more here. If
someone wants references on the subject please ask. For now I say that
there are three or four books on the subject...


J. Augusto