Can anyone help me to explain why different PFD can cause the different result ？
As the attached two files show，the phase noise @10kHz in the 8M.jpg is good (about -90dBc/Hz) , while its poor in the 8.4M.jpg （only about -70dBc/Hz）.
The output frequency bothe is 2690MHz.
The PFD is 8MHz in the 8M.jpg and channel space is 100KHz （because there‘s a 50kHz spur been showed , so this spur is normal.）
The PFD is 8.4MHz in the 8.4M.jpg and channel space is 400kHz. (but there's a high noise at about 10kHz , this is abnormal.)
Other registers for the two PFD freq are the same , expect the R0 (due to freq must be the same).