I have downloaded the ADI Visual Analog Software and AD9864_74 SPI GUI to evaluate the AD9874. I use the test conditions as below:
IF =15.75MHz, -12dBm
LO=18MHz, 1 vp-p
the AD9874 registers are setting as below:
I use the Visual Analog software, the AD9874_16b average FFT, the data capture is setting as below:
And the result is as below, why result looks so bad?