How to align (synchronize) the outputs of two AD9516-1

Hi, thanks in advance for your attention and reply.

 I now want to use two AD9516-1 chips on two different boards, and I want to synchronize the output of the two chips.

For example, two AD9516-1's out0 ports output 250MHZ signals. I want their phases / timings to be aligned. Let me talk about the work I am doing and the problems I have encountered.

 1. Below is my block diagram. A signal source generates a signal with a frequency of 1 GHz, and then enters two ADCLK 925 after passing through the power divider. It is then entered into two AD9516-1. Both 9516 SYNC pins are connected to a switch through a buffer. The AD9516-1 does not use a VCO divider internally. It directly inputs from the CLK and then passes through the channel divider. The output is obtained after dividing by 4. My idea is that when I press the switch, the output of the two AD9516-1s can achieve alignment.

 2. As a matter of fact, when I press the switch, their output is not aligned. The yellow and green lines are the output signals from two different ad9516-1. As shown in the three pictures below. As can be seen from the figure, the output has several states, and alignment is one of them. When I press the switch repeatedly, many things happen. In other words, my idea cannot achieve the alignment of the two 9516 pieces.

 3. So, is it possible to achieve output alignment between different AD9516-1? If so, how should it be achieved? Is the idea I mentioned above feasible or completely impossible?

 Many thanks.