We are using No-OS driver to configure AD9364 in our project where we are using TxA port for higher frequency and TxB for lower frequency. When we transmit signal with LO frequency of 300MHz in TxA, we are seeing spectrum with increased noise floor and response similar to phase noise roll off. However, when the same signal is transmitted in port TxB, we are seeing a clear spectrum.
Then for further debug, we swap the port configuration such that the TxA will transmit lower frequency and TxB, higher frequency. This time we are facing the clear spectrum(same LO frequency for both port) in both the ports. What might cause the issue? Is this anything to do with software?
I've attached the poor spectrum and good spectrum response below,
This can be a configuration issue.
The Tx quadrature calibration stores a separate set of calibration results for the Tx_A and Tx_B output paths. If using both the Tx_A output and the Tx_B outputs, run the calibration twice, once with each output path selected. Hope you are doing this in your software.
So, once we select the rf port setup in the middle of the code,is calling "ad9361_run_calibration(phy, TX_QUAD_CAL)" appropriate enough?
During initialization itself you can do this cal twice with each paths selected.
Thank you for your assistance. The spectrum is deteriorated because of matching issue. It is not AD9364 issue. We are using a pole-zero filter at Tx port to remove the odd harmonics from AD9364. That filter is causing the issue.