AnsweredAssumed Answered

AD9833 Output Filter

Question asked by coburn on May 12, 2011
Latest reply on May 17, 2011 by coburn

Hey there,


I am currently trying to create an output filter to remove the harmonics created by the AD9833 DDS and wondering about the 200 ohm output resistance, which looks to be in parallel with the output. I am trying to design a 5th order elliptical filter with a cut off at 2MHz and I think I am having some impedance mismatching issues because when I attached the filter to the output of the evaluation board the amplitude of the output is reduced by around 40dBm.


So when I design a filter does the 200ohm in parallel need to be included in my design, or is there another value of series resistance that I should be using for the input resistance to the filter?