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Unwanted spurious noise in AD9914

Question asked by Harsha@528 on Jul 16, 2015
Latest reply on Jul 23, 2015 by sitti

Hi all,

 

We have designed DDS based board using IC AD9914. The application is to generate frequency range of 0.5-18 GHz.DDS board is generating frequencies from 0.4-1.6 GHz. There after doubling, amplification and switching is carried on to generate the final band of frequencies. there are 2 main problems am facing,

1) the IC AD9914 is getting heated very fast.

2) The unwanted spurious is very much high at the output of the DDS. As the chain up consists of amplifiers this is becoming still more worse.

3) We see sudden rise of noise floor and spurious and subsides immediately leaving the spurious level high.

Am attaching both the pics

The behaviour of the IC is intermittant

Please suggest and find the attachment.

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