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FMCOMMS1-DAC Spurs with full scale

Question asked by xanyanou on Mar 22, 2017
Latest reply on Apr 10, 2017 by rejeesh


I have a Zedboard with a FMCOMMS1 board and I'm using the design reference.
For example when I try to send a single tone at 5MHz (for example) if the scale is set to 0.5 or lower, there are no problem.
But if I set the scale to 1, there are a lot of spurs (at 15, 25, 35, ..., 125MHz). My question is why ?
Why data in full scale makes spurs or noise up to 120MHz.


I have this question because, I tried to send my own data to the DAC. It is working, but I have the same spurs/noise, even if I divide my data by 2 or 4 or 8 to reduce the scale. So that's why I would know why the full scale doing this.
It is looks like to a DAC overload.


Thank you in advance