Attached test results for Input to Output Gain look like non-linearity.
Please let me know about the reason of non-linearity.
I assumed that output gain is constant, because not using input Gain adjustment.
But below test results are change the output gain.
I want to know these results depend on DAC38RF80 spec or external problem.
※Orange: 10dB, Blue: 5dB, Light blue: 0dB, Green: -5dB
Please see test condition below;
・Signal generator (SG) output CW: 3.96GHz
・DAC38RF80 receive signal from FPGA, and confirmed DAC output signal on spectrum analyzer (SA).
・On above condition, DAC output gain measured on the condition of input level and DAC GAIN changing.
(DAC GAIN are set 10dB, 5dB, 0dB, and -5dB)