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Spurious tones in the FMCOMMS5 reference DDS design

Question asked by SuDhaMani on Mar 21, 2017
Latest reply on Apr 21, 2017 by sripad

Hi

 

I am working with ZC706 with FMCOMMS5 board. In my design I am using no-OS-2016_R2, vivado,SDK16.2 versions. In the reference No OS driver, I am selecting DDS DAC, 1R1T mode. In the spectrum analyzer I am observing the output as attached below. DDS tone is appearing at 1MHz(default design), in addition to that I am seeing spurious/images in the output (figure_1). I tried eliminating this spurious by increasing the TX attenuation, all except one tone at center frequency are eliminated(figure_2).Any further Tx attenuation affects the DDS tone,but not the center frequency tone.How do I eliminates these spurious tones to get pure DDS tone at specified frequency? Any reply would be helpful. 

 

Thank you.

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