I am working on a FM project using Ultra-scale Zynq FPGA and AD9361. are sent from FPGA to AD9361for mixing via HPC0 connector. I configured the AD9361 register using the script generated by 9361 software and got the frequency spectrum of tx data as figure below.
In the figure, signal after mixing is suppressed at about -25dB which is lower than the suppression of intermediate frequency point at 2.5GHz (about -10dB). Actually, I like to get a spectrum as figure below. Is it possible to complete it via register configuration or I have to modify my FPGA hardware design.