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AD9838 DDS Amplitude adjustment

Hi, is it possible to adjust the amplitude of the sine wave in the AD9838. It is described as a waveform generator and the https://www.analog.com/media/en/training-seminars/design-handbooks/Technical-Tutorial-DDS/Section1.pdf App note shows that a typical DDS has a 12 bit AM (Amplitude modulation) adjustment. Any help would be much appreciated. Thanks

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  • Hello, no, no reply yet. It looks like the phase register only sets the phase and there is no way to adjust the amplitude. I did try adding some 10uF caps to the Ref output and the FSADUST output and while they do ramp the waveform, it is not great - curved and nonsymmetrical. The RESET bit turns everything off and on. 

    If there was another similar chip which had a amplitude adjustment, we would happily move to it but I cannot see any in the search.

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