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ADF4360-9 Harmonics

Question asked by TimW Employee on Sep 28, 2009
Latest reply on Oct 1, 2009 by BobC

Using the ADF4360-9 to produce output frequencies in the range of 70MHz to 90MHz.  Using both outputs, but using them singled ended (kind of a dual output), but both outputs are driving 50 ohm impedance.  Using a 150nH inductor to bias up the RFout, instead of the 51 ohms resistor.

 

I'm seeing higher harmonic content than the data sheet would indicate, though the datasheet doesn't give any conditions on the harmonic measurement.  The second order harmonic is down only -9dBc (compared with -16dBc typical) and the third is down only -12dBc (compared with -21dBc typical).

 

Are these measurements fairly normal?  Are there performance differences over different frequency ranges?  What can one do to reduce the harmonic contect coming out of the VCO?

 

Thanks,

Tim

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