Hello,
I have repeated the tests and observed a similar behavior on two of our AD9361 eval boards (9361CE01C). Note that the degradation observed on the ADI evaluation platforms is a few dB worst compared to the results presented in the previous report (our platform).
The problem can easily by repeated by using a standard LTE FDD 10MHz profile by configuring the correct Tx/Rx frequency pairs. Note that the problem is more severe when the AGC gain is high (i.e. near 76) and the Tx attenuation is near 0. Here are a few Tx/Rx pairs you can use to replicate the problem on your side.
Tx (MHz) Rx (MHz) BB Spurs (MHz) Tx VCO (MHz) Mixing spurs
1500.000 1200.250 1.25 6000.0 TxVCO - 5xFrx
1500.000 2001.000 3.00 6000.0 TxVCO - 3xFrx
2000.000 2666.000 2.00 8000.0 TxVCO - 3xFrx
2155.000 1724.200 1.00 8620.0 TxVCO - 5xFrx
Make sure to terminate the Rx/LNA input ports otherwise the results can be worst. On my setup all ports are properly terminated (Tx and Rx).
Please let me know if you need additional information.
Regards,
A.