AnsweredAssumed Answered

EVAL-AD5933 incorrect phase measurment.

Question asked by Bilal_Ahmad86 on Jun 24, 2015
Latest reply on Jun 25, 2015 by mcee

Hi all seniors,

 

as i am new here, so need some help. I am using eval-ad5933 for measurement of impedance. firstly gain factor is calibrated with known Z=220k and Rfeb=220k, then when i place 100pF capacitor the impedance calculation by using the formula Mag= sqr(R^2+I^2) is correct, unfortunately phase calculation from the formula is not correct, phase values downloaded from visual basic software provided by analog devices are does not match with values calculated with Phase=tan-1(I/R)*(180/PI).

 

I have read the document http://www.analog.com/media/en/technical-documentation/application-notes/AN-1252.pdf

but still not understand, how to get the system phase and then the phase introduced by the impedance (100pF) in my case.

what i should do? i am using range 1 for excitation signal.

 

 

Regards

Bilal Ahmad

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