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ADF4350 spurious

Question asked by RFmysoul on Mar 14, 2012
Latest reply on Mar 14, 2012 by rbrennan

Recently I tested my ADF4350 card


1.The fundamental spectrum(2.2 -4.4)GHz is fairly pure


2.When I use divider in PLL to  generate frequencies less than 2.2GHz (say1.2GHz)I can see

lot of spurious In addition to Harmonics.Those spurious are with an interval of rf_fundamental/6=2.4G/6=400MHz


3.I used PLL of some other company  whose fundamental is from 1.5 to 3GHz

to generate divided output similar to what I did with  ADF4350 ,but in this case there is no spurious

at all.I could see only the harmonics also  the harmonic levels are good better than 30dBc


4.The  configuratuion is



feedback path=divided path


5.Please refer the attached plots of  1.2GHz spectrum