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reference clock  harmonics in ad9361

Question asked by padma@1969 on May 3, 2017
Latest reply on May 5, 2017 by Vinod

We  are evaluating chip for using it in 4 to 5GHz band using z706 and FMCOMMS4  boards. what we have noticed is

case 1:

   IF LO frequency is at multiples of reference oscillator  say 40MHz in our case . we are getting inband spurious as below

   @188k    level  is    -46dbc (RF Tx LO=4.4GHz, ref oscillator freq=40mhz ,and 110 harmonic of ref oscillator is 4.4GHz)

   @376k    level is      -60dbc(RF Tx LO=4.4GHz, ref oscillator freq=40mhz ,and 110 harmonic of ref oscillator is 4.4GHz)

case2:

   If difference between RF Tx LO and RF Rx LO frequency is 1MHZ .then harmonics of 1MHz are observed irrespective of reference frequency harmonics.

case3:

    If RF Tx LO is at  4.5GHz which is not multiple of 40MHz and RF RxLO is 4.401GHz,then also we have noticed ,

   How to resolve the issue with AD9361. what extra  tuning or hardware i need .Please give advice to proceed  further.

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