We have observed a 6KHz component adding to the ADC signal while transmitting and receiving at the same frequency (2155MHz) on the same FMCOMMS1 board. The following is the screenshot of the captured samples on chipscope while feeding 0s to the DAC.
Blue: in-phase channel Red: Quadrature Channel
We also observed that this beat signal was received only on the same board and not on an other FMCOMMS1 board. Is this related to this(
http://ez.analog.com/thread/20764) problem? If yes, will these BOM improvements(http://wiki.analog.com/resources/eval/user-guides/ad-fmcomms1-ebz/hardware/bom_improvements) do the job? These are for Rev. B, right?
And, are there any other concerns to address for a stable two way communication between two FMCOMMS1 boards?