I used demodulator ADL5380 to convert my measured signals to DC I/Q signals by removing the baluns on its evaluation board. And then I connected ADL5380 with ADRF6510 evaluation board (I also removed the baluns at the input and output port) to filter and amplify I/Q signals. However, I found that the outputs of ADRF6510 board were not DC signals, only noise. And the output common mode voltage of ADRF6510 board is 2.5 V. I also did not see this DC level at the output of ADRF6510 board.
I tried to use ADL5380 board to convert my measured signals to 100Hz I/Q signals and connected these I/Q signals to ADRF6510 board. I found the outputs of ADRF6510 board were 100Hz signals and this connection performed well. I do not know why ADRF6510 board cannot filter and amplify the DC I/Q signals.
Would you please give us some suggestions on this problem? And is this problem caused by AC coupling capacitors (C7 to C10) on ADRF6510 board? I am appreciating your help!