I'm using AD9910 to generate a sinusoidal signal
The output signal amplitude decline sharply when the output signal frequency over 200MHz
when the output signal frequency exceeds 320MHz，the amplitude decline to zero，the output signal is gone. when the frequency behind 200MHz，the amplitude of the output signal is 330-480mv.
1. I already enabled the inverse sinc filter，if I disabled inverse sinc filter ，the output signal amplitude is dropped from 0.7V to 0V. same with enabled inverse sinc filter.
2. VCO frequency range bit setting 101 already
3. I changed the output filter and the amplitude still dropped sharply
what should I do? thank you
I have some questions to assess your setup.
1. Are you using the evaluation board? If not, is it possible to share your schematic?
2. What is the frequency and power level of your reference clock? Are you using the PLL?
I‘m trying to generate a 400MHz sin wave with 1GHz dds clock
I may be wrong but that looks very like the schematic of a AD9910 board that I got of ebay.
The main difference is that the capacitors at the top part of the output signal filters are all to ground (somewhat similar to the Analog Devices evaluation board) rather than in series to the output pin.
However I get a very similar outcome (roll-off about above 100MHz or so)