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AD7766 Phase response

Question asked by vien on Jan 5, 2015
Latest reply on Feb 1, 2015 by KarenNE


I am using AD7766 to digitize a reference AWG signal from 0.1 to 50Hz.

When I plot the output of AD7766, I see a the digitized samples has a changing phase delay relative to input frequency.

The delay appears to be from 45 degrees to 70+ degrees increasing from 0.1 to 50hz.

I am expecting a FIXED phase delay value, not a changing one since the ADC is operating at 62.5Ksamples/s and input frequency is very low.

Is this a phase response due to AD7766 internal LPF filter? The spec does not show any phase response plots.

How do I compensate for this (to flatten out the phase response)?