In datasheet on AD9694 (Page 7), the value of CROSSTALK is indicated only for the frequency of 155 MHz. Are there data from CROSSTALK on other frequences? I'm interested in the range 250-500 MHz.
The crosstalk is dependent on a myriad of factors that are external to the AD9694. I would use the datasheet as the best case guide for crosstalk. There is a possibility that the crosstalk could degrade by a few dB at higher frequency but we have no data on it. We know that our evaluation board has some limitations that arent suited to best crosstalk. So we do not feel comfortable taking data on our evaluation board. If for example, you laid out the front end networks such that one channel was laid out on the same side as the AD9694 and the adjacent channel was laid out on the opposite side as the AD9694, you could get better isolation.