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.