ADIsimPLL

Hello,

I am using the ADIsimPLL for the first time to simulate the ADF4007.
Question 1: The output frequency defines the reFference frequency so that there is no frequency error or phase error between them.As show in Fig.1, why is the time domain result showing a lock on phase and frequency when there is no error?
Question 2: As show in Fig.2,The phase detection output is always negative, and the error result will deviate more and more from zero?
Question 3: Does ADIsimPLL have the function of error notification?

Thanks,

Ning

                        Fig.1                                                                                                                         Fig.2