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why the output of ad9129 has very large harmonic?

Question asked by touchblue on Jul 12, 2018
Latest reply on Jul 12, 2018 by touchblue

I'm debugging ad9129' s output for several days, and the output wave is so strange, it can't be used, why?

But i have checked the my circuit with the reference design of ADI, also i measured power supply of ad9129 on my board. also emi  filter  to power supply. using external 2.8G clock source as reference clock to ad9129.

 i powered on it, and config the register according section of "start-up sequence" of the AD912 datasheet 。On the board, using xilinx V7 FPGA lvds port to driver AD9129,setting DDS output frequence to 200MHz or other value.  


i find the DAC has wave ouput . But using the oscilloscope measure, it can see wave have jitter. using spectrum to measure, the output have larger harmonic wave.


so who can help me to resolve the issure. thank you very much.