I am trying to get Mathematica to output the Z-transform of x[n]=-u[n-1]. I know what the z-transform of this function should be before and after simplification however, I have not been able to get Mathematica to produce the expected output. Any suggestions? Am I using the function incorrectly? Or am I getting the correct result and not understanding what I am getting? Attached are the expected results, simplified and unsimplified, and my various attempts at using the Z-Transform command.
Hi Jon
I am afraid, you will have to learn much more about Mathematica syntax.
ZTransform[-u (n - 1), n, z]
Out[1]= (u (-2 + z) z)/(-1 + z)^2
ZTransform[-u (n - 1), u, z]
Out[4]= -(((-1 + n) z)/(-1 + z)^2)
Robert
Thank you for the explanation. If I am required to do this in 2 steps, is there a way to then combine these results and simplify?
What two steps are you talking off?
You have to now which is your variable, is it n or is it u? After this only one step is left.
If you are expecting the following result:
-(1/(1 - z^-1)) + 1
You could perform the inverse transform:
InverseZTransform[-(1/(1 - z^-1)) + 1, z, x]
Out[8]= -1 + UnitStep[-x]
Robert