AnsweredAssumed Answered

AD9910 Multiplier Problem

Question asked by sat_isar on Mar 15, 2013
Latest reply on Apr 9, 2014 by mantow

Dear Analog Devices,

 

We are writing you from an Italian company which is working on the development of a remote sensing system.

Since we are working with the AD9910 setup and we are experiencing an issue very similar to one already discussed on the ez, we are writing to you to kindly ask is this problem has been fixed.

In particular, we refer to the issue described in the "Phase Noised Plots AD9910" thread (http://ez.analog.com/thread/13598).

We are providing an external 10 MHz OCXO clock to the DDS board and we want the AD9910 to generate a 100 MHz signal. We set the multiplier to produce a 800 MHz signal clock to let the DDS to work with it.

Unfortunately, the 100 MHz output signal we get shows severe phase noise levels, thus making it totally unuseful to our purposes. We do not have a phase noise meter, but just with a spectrum analyzer we noticed phase noise and spuries around -40dBc/10kHz.

As experienced with the tests performed by the user of http://ez.analog.com/thread/13598, we always get a bad phase noise level even if we change the filter-loop parameters value.

Now, we are wondering whether you solved the problem described above (might be, by changing some R-C values) or if your experience in this topic suggests that there is no way to obtain better results than those we are getting now.

Thank you in advance for your reply.

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