AnsweredAssumed Answered

Where does the harmonics of carrier come from and how to get rid of?

Question asked by chenxiee on Jul 19, 2016
Latest reply on Jul 26, 2016 by Vinod

Hello, everyone.

     I am working on a AD9361 design with a customly designed AD9361 hardware. I am using STM32F407 to config AD9361. Basically it works well. But I found that the 2,3,4,5 harmonics are quite strong. as shown by the following to figures.
149955266562264915.jpg

  In the above figure, carrier is 600MHz, and you can see a strong harmonic of carrier at 1.2GHz

864448133445579300.jpg

In the above figure, we set tx carrier to 80MHz, we can see a lot of harmonics.

     My questions are : Where does the harmonics of carrier come from and how to get rid of?  I am using a fully customed AD9361 hardware.

     When I reduce Tx power, all the harmonics decreases correspondingly as with the carrier.

     Thanks.

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