Dear,
I am trying to understand the impact of crosstalk between two "parallel" cables. I have searched information online and my first understanding of crosstalk is as follows:
I found this equation for the crosstalk voltage:
And this equation for the calculation of the parallel line capacitance C:
With Epsilon_r = 1.0006 (permitivity of air (not really true since I should also consider the permitivity of the skin of the cable)) and Epsilon_0 = 8.85 x 1012 F/m (permittivity of free space).
I have input these equations on an excel sheet (attached if anyone need it) and tried to play with different parameters to see their impact but crosstalk is not clear anymore for me (I naively thought it was)... My issues are:
Thank you in advance!
Best regards,
Ludovic
I am trying to understand the impact of crosstalk between two "parallel" cables. I have searched information online and my first understanding of crosstalk is as follows:
 A current into a wire will produce a magnetic field
 A varying magnetic field will create a reverse current in nearby cables
 A constant magnetic field will not create a reverse current
 So crosstalk is when victim cable(s) are under the effect of the reverse current of a varying magnetic field of a disturbing cable.
 Higher current variation will imply higher magnetic field variation and so higher crosstalk coupling
 A square signal will have higher crosstalk coupling than a sinus (sharp edges)
I found this equation for the crosstalk voltage:
And this equation for the calculation of the parallel line capacitance C:
With Epsilon_r = 1.0006 (permitivity of air (not really true since I should also consider the permitivity of the skin of the cable)) and Epsilon_0 = 8.85 x 1012 F/m (permittivity of free space).
I have input these equations on an excel sheet (attached if anyone need it) and tried to play with different parameters to see their impact but crosstalk is not clear anymore for me (I naively thought it was)... My issues are:
 In these equations I don't see any link with the fact that the crosstalk coupling happens during a variation, shouldn't we have an integral somewhere in the equation?
 Since no integral in the equation, I don't see how the shape of the disturbing signal impact the crosstalk coupling
 Also it doesn't show how a higher current would have a higher crosstalk coupling
Thank you in advance!
Best regards,
Ludovic
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