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AD9361 phase noise at 2440 and 4880MHz

Question asked by kbs on Oct 6, 2014
Latest reply on Oct 9, 2014 by tlili

I've noticed higher LO phase noise at 2440MHz and 4880MHz. I initially thought it may be caused by frac-N boundary spurs since it is near an integer multiple of the 40MHz ref frequency, but 4840MHz is clean. Attached are SPA captures using the 10.txt test pattern with 25MSPS sampling rate. When I look at constellation diagrams with complex data near these LO frequencies, the constellation shows phase wobble as well. Do you know what may be causing this noise?

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