Running the AD9788 at 714.42 MHz with x4 Interpolation giving a DATACLK frequency of 178.605 MHz. DATACLK needs to be delayed for proper data alignment. As soon as the delay is enabled, whether in Auto or Manual mode, a noise spur shows up at (178.605 - Fout) where Fout in this case is 98.5 MHz.
Why is the delay circuit creating the noise?
How can I overcome it?