what is the phase offet in pfd-charge pump

can u please explain the phase offset in pfd-charge pump
and how i measure in cadence tool..\
please give me any doc thesis and realted material
regards\

guys please reply the diff between the deadzone and phase offset and how these can be measured.
it will be really appreciable

For dead zone, it's the time the charge pump takese to respond and supply constant current .If the phase difference between the reference clock and the divider output is smaller than this time ,the PFD/CP can't detect it .To mitigate its effect, a delay is usually placed after the AND before the reset of the flip-flops which will cause an increase at both the UP and DOWN signals' periods with that delay and thus can make the pulses be detected by the CP .
Concerning the phase offset, I'm not sure, but if the UP current isn't equal to the DOWN current due to mismatch, non-linearity exists at the origin which has a severe effect on the delta-sigma noise at folds the high frequency noise to lower frequencies into the pass band of the PLL .To avoid that ,static phase offset is applied to move to a linear range i.e not operating at the origin .This is performed by applying a static constant current between the CP and the loop filter (you can consider that as applying cons current added to the CP current) .