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Why am I unable to repeat the phase alignment between RFin and REFin using the ADF4106?

I an using "Analog Devices Int-N PLL Software" with the USB interface to control an ADF4106.  Is it possible to achieve the same phase relationship between the RFin and REFin signals for a given set of device settings after power-cycling the ADF4106 and VCO?

I have tried the "Initialization Latch Method" and the "Counter Reset Method" as described in the ADF4106 data sheet.  It seems that for frequency settings where RFin is not a multiple of REFin the resulting phase relationship is always different after power-up.  I was expecting that the internal reset pulse or the counter reset operation would ensure that a consistent phase relationship would result.  It does not.  In fact, any counter reset that is executed results in a different phase relationship for the cases where RFin is not a multiple of REFin.  Am I missing something?

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  • "Please note that consistent phase relationships do result if the RFin setting is an integer multiple of the REFin frequency." Can you give me example settings of this situation (reference frequency, PFD frequency, RF output frequency)? Also, give me an example of the settings where it fails.

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  • "Please note that consistent phase relationships do result if the RFin setting is an integer multiple of the REFin frequency." Can you give me example settings of this situation (reference frequency, PFD frequency, RF output frequency)? Also, give me an example of the settings where it fails.

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