For a Phase Lock Loop (PLL) with a Gilbert cell mixer based phase detector, to maintain lock, the phase error between incoming reference signal and VCO output must be maintained between

For a Phase Lock Loop (PLL) with a Gilbert cell mixer based phase dete

1.	For a Phase Lock Loop (PLL) with a Gilbert cell mixer based phase detector, to maintain lock, the phase error between incoming reference signal and VCO output must be maintained between
A.	0 & π
B.	0 & π/2
C.	0 & 2π
D.	π & 2π
Answer» B. 0 & π/2