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ADF5355 Eval Board Spur Problem

Question asked by altanalp on Jun 14, 2016
Latest reply on Jun 20, 2016 by MRichardson


Hello,

 

We are working on ADF5355 Eval Board with the eval software. Eval board comes with 122.88 MHz clock source but we are testing the hardware with external 100 MHz reference sourse as our final hardware going to be designed for the 100 MHz reference signal.

 

Below, you will find 4 images, first 2 belongs to the 4000 MHz (control software + specktrum) and the last two belongs to the 4000.1 MHz. As you can see, there are lots of high level spurs close to the 4000.1MHz signal.

 

Are there any ways to remove the spurs/reduce levels? 100kHz channel spacing is not so high and we expect the ADF5355 chip to cover 54 to 13600 MHz band with acceptable spur levels.

 

We shared the control software screenshots to get feedbacks on the register values.

 

Thanks in advance

 

Center: 4000 MHz, Channel spacing: 100 kHz, no spur:

 

4000-no-spur.png

4000.jpg

Center: 4000.1 MHz, Channel spacing: 100 kHz, to much high level spurs:

4000.1-spur.png

4000.1.MHz.jpg

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