I was using an oscillator to drive AD9956, but I found output at SYNC was seriously distorted.
The oscillator is 20Mhz, with a resistor of 24Ω.
Is the Oscillator working OK? How can I fix this?
If you're not already, you should ac couple the REF CLK source above to the DDS? Also, the max voltage swing on each REF CLK input is 1V pk to pk. You'll need a voltage divider if your oscillator is swing rail to rail (0v to 3.3V). I have attached the AD9956 evaluation board schematic for reference.
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