AD9852: Evaluation board output amplitude is always full scale?

Document created by analog-archivist Employee on Feb 23, 2016Last modified by analog-archivist Employee on Feb 23, 2016
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I used AD9852EVB to do experiment to generate a sine wave. Attached is the PC
software's configurations, here "the output amplitude is always full scale." So
the DDS's output current should be 0-10mA, then the voltage should be 0V-500mV.
Figure 2 is the output after low-pass filter. The real output voltage is about
50mV-580mV. The minimum voltage isn't 0V, there is a bias voltage.
How do I calculate the DC bias voltage? If the Rset resistor's value is
changed, will the bias voltage vary?

 

This is due to the Sinc Effect. Below wave is a 115MHz signal, because of the
Sinc Effect, so the amplitude will attenuate. After I enabled the inverse Sinc
Filter of AD9852, the DDS's output can reach 0V.

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