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AD9777 overall delay

Hi

I am using the AD9777 in an existing design of a digital feedback controller, so actual input-to-output time delay is critical.

What is this delay for the AD9777? (the datasheet only gives the settling time, measured from the start of the analog output).

Is the overall delay and "group delay" the same thing? The AD9777 datasheet lists "group delay" under terminology, but doesn't actually use the term anywhere else in the datasheet.

Kind regards

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  • Thanks Tguy

    This is very useful information. What is the digital delay with no (x1) interpolation and no (1x) modulation?

    And as for the units, do I understand it correctly that ie. 2x interpolation 1x modulation would be 56 * 1/f_dac?

    In this case, with an input data rate of 100msps, f_dac = 200msps => 5 ns period =>

    Digital delay = 56 * 5ns = 250ns

    Total delay = 250ns + settling time of ~11ns = =261ns.

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  • Thanks Tguy

    This is very useful information. What is the digital delay with no (x1) interpolation and no (1x) modulation?

    And as for the units, do I understand it correctly that ie. 2x interpolation 1x modulation would be 56 * 1/f_dac?

    In this case, with an input data rate of 100msps, f_dac = 200msps => 5 ns period =>

    Digital delay = 56 * 5ns = 250ns

    Total delay = 250ns + settling time of ~11ns = =261ns.

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