Question about AD9525

  Sir:

   I have some questions about AD9525.

(1) In the page 8 of the datasheet , table 12 give the "clock output absolute time jitter". What does it mean? Does this jitter include the performance of the external VCO?

(2) Is there a device that is in the same performance as AD9525 but without the clock distribution function?  A single jitter cleaner with one output satisfy my requirement.

(3)Compared with AD9557, the performance of AD9525 improve a lot. Why the phase noise of AD9525 is much better than AD9557?

Thank you!

Regards

Jacky

2013-06-17