In article , "W3JDR"
writes:

Dead-zone = phase noise. Very little dead-zone = very little phase noise.
Bigger dead-zone = bigger phase noise.
You can interpolate the rest for yourself.

I have to disagree with some of that.

First of all, a "dead zone" or the almost-exactly-in-phase condition,
occurs at only one VCO frequency where the control voltage sets
up the frequency for that in-phase condition.

Yes, at that exact frequency, there COULD be some phase noise.
But, the phase noise may NOT be from this "dead zone" effect.
Phase noise can come from MANY different sources. If it occurs
well away from the in-same-phase "dead zone" then the phase
noise is NOT caused by any "dead zone."

The relative phase between signal and reference inputs to a PFD
correspond to the VCO control voltage (times the charge-pump or
integrator circuit constants). Signal and reference phases when
in lock will always be offset from one another, one leading and one
lagging. A good loop will show a constant offset of phases even
when both inputs hold a constant phase.

Len Anderson