I am trying to realize an application for LO changing frequency.
For that, i am using the BIST and transmitting an LO at 2GHz.
To here everything looks ok.
From here - i am trying to jump in frequency, i am using register '005' in order to change dividers (from value of 4 to 128).
Of course - i am also calculating new integer and fractional factors for the PLL.
My problem is in low frequencies - 100Mhz ~ 300 Mhz, or in other words: my problem rise in high PLL dividers values.
The spectrum looks full of spurs with many harmonies of the BIST signal.