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AD9912 Phase discontinuity??

Question asked by DavidLee on Aug 28, 2014
Latest reply on Sep 10, 2014 by DavidLee

Here is the description of the phase tuning word for the AD9912

Allows the user to vary the phase of the DDS output. See the Direct Digital Synthesizer section. Register 0x01AC is the least significant byte of the phase offset word (POW). Note that a momentary phase discontinuity may occur as the phase passes through 45° intervals.

I'm concerned about the statement "momentary phase discontinuity may occur". What!?

 

Can anyone shed some light on this? How big a discontinuity are we talking here? pi/100, 100*pi?

Is it a transient phase shift or is it a step discontinuity in phase?

 

Under exactly what conditions does this occur? Can I reproduce this in the lab?

 

This is pretty important for my application.

 

Cheers,

David

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