I am working on a FM project using Ultra-scale Zynq FPGA and AD9361. Orthogonal Signals (generated using DDS IP core) are sent from FPGA to AD9361for mixing via HPC0 connector. Orthogonal Signals (I/Q) sent to the AD9361 is tested on the FPGA HPC0 pins, the clock and data signal can be correctly observed on the oscilloscope. AD9361's registers is configured using Zynq processor via SPI interface. I have used AD9361's 0x3F4 register (BIST generator) to test the register configuration and the result is correctly observed on spectrum analyser. Therefore, I think the registers are correctly configured.
Spectrum tested using BIST is showed below.
However, when the FPGA is programmed to sent data to AD9361, only a carrier waveform can be observed on the intermediate frequency point. In my mind, even though the Orthogonal Signals generated from FPGA design is not completely correct, something changes on the spectrum should be observed. Therefore, I suspect that the data haven't been successfully sent to the AD9361's tx channel. However, the FPGA pin is successfully tested and the data is successfully captured. I have worked to solve this problem for 2 days but no solutions.
Spectrum tested by programming FPGA to sent data to AD9361.