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View Full Version : converting from s to z domain


LM741
Sep29-06, 11:11 AM
hey guys ...
having issues transforming from s domain to z domain.

Take this as an example and transform from s to z:

H(s) = 20/(s+20)

now using:s = (1/T)lnz (which i got from lecture notes)

i get : 20/((1/T)lnz+20)

the actual answer is: 20z/(z-e^-20T)

To get this answer, my prof used the followin: s +si = 1 -(e^siT)z^-1.
But surely i should get the same answer using s =(1/T)lnz???

thanks