My AD6649 has been in working condition, and the data output terminal of the chip has been outputting real data. I have obtained the data of two channels A and B from the output real data.
My goal is to recover the unambiguous IQ signal that goes through the FIR filter but not through the fixed fs/4 NCO. Because the phase of the signal is important to me.
For the data of a certain channel (such as the B channel), I decomposed two mutually orthogonal signals (according to the relationship of fs/4), one of which is I and the other is Q (see figure).
But I can't distinguish which one is I and which is Q. I don't know if there is any way to clearly distinguish I and Q, do you have any suggestions? Or can I just choose another device instead?