Any Tips or suggestion with this kind of abnormal signal problem?

[Whitecloud010]

Hi. I'm using N210+UBX for my research. I recently struggle with this kind of signal.

I used GNU Radio, and RF parameter that i used is as follows. USRP transmit some data signal and following CW(which is common in UHF EPC-gen2 RFID). And I tried to cancel the self-interference with ZAPD-20-S+ power combiner.

Center Frequency : 910MHz

ADC rate : 400K

Rx gain : 0

Is there anyone who seen this kind of thing? What was the problem? If you know anything plz help me.