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AD9361 - PLL Dividers - Register '005'

Question asked by ihorev on Jun 23, 2015
Latest reply on Jun 23, 2015 by DragosB



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.



Please advice