I have a part I need to measure frequency out of. Frequency range is 10MHz to 1GHz with LVCMOS,LVPECL and LVDS configurable output drive. Measurement instrument is limited to 25MHz and thinking of using N,R divider of PLL to scale down to measurable range. Is this possible with say ADF4106?

Yes, the input sensitivity and slew rate. You will need to scale down the amplitude. You can do this by placing a resistor (~100 ohm) between the two differential signals. Both signals should have have a series capacitor. See image.

You will need to meet the prescaler requirements. You can choose the prescaler division ratio in the Function Latch of both the ADF4111 and ADF4106.

The duty cycle is 1/N * 100%; where N is the total divide ratio (N = BP + A).