I am doing RX local frequency sweep test, and RX EVM performance is monitored.
What I did is to configured AD9361 to be FDD mode and fixed TX local frequency at 1700MHz, then changed RX local frequency from 400MHz to 4GHz. A modulating signal has gave to RX of AD9361. However, I noticed that EVM get worse at lower frequency (probably below 1GHz) and I found out AD-FMCOMMS3-EBZ has the same phenomenon (AD-FMCOMMS3-EBZ Specifications [Analog Devices Wiki]). Do you know the root cause? And how should I do to improve it? Thanks in advance.