Rs and Xs calculation

[Magda]

Hi, I was searching in help but couldn't find. If I use the W1-C1-DUT-C2-R-GND circuit what is the formula to calculate series resistance and reactance? I mean how the WaveForms calculate those values.

Thank you for help. 

BR

[attila]

Hi @Magda

For  W1-C1-DUT-C2-R-GND is:
re = magnitudeRatio*cos(phase)
im = magnitudeRatio*sin(phase)
gp = 1.0/rReferece + 1.0/rProbe
bp = cProbe*2*PI*hz
y = gp^2 + bp^2
rs = (im*bp+gp*(re-1))/y
xs = (im*gp-bp*(re-1))/y
+ open/short compensation

[Magda]

Hi @attila

Thank you for very fast response. That is very helpful. I only does not understand what magnitudeRatio is meaning and how to know the value.

Basically I am asking because I use Diligent Impedance Analyzer measurements as a reference. 

The second measurement is done with the bench function generator and oscilloscope with the same circuit. I measured the V1, V2 and phase diff with oscilloscope and tried to calculate the impedance, but my calculation impedance results are not the same as from Analyzer..

[attila]

Hi @Magda

The magnitudeRatio is C1/C2 FFT magnitude at the frequency step.

[Magda]

Thanks a lot!