| Line 24: | Line 24: | ||
<math>= 9 z^3 + 4 z^2 + z </math> | <math>= 9 z^3 + 4 z^2 + z </math> | ||
| − | <math>= z^3 (9 + 4 z^-1 + z^-2) </math> | + | <math>= z^3 (9 + 4 z^(-1) + z^(-2)) </math> |
Write it here. | Write it here. | ||
===Answer 3=== | ===Answer 3=== | ||
Revision as of 15:20, 12 September 2013
Contents
Practice Problem on Z-transform computation
Compute the compute the z-transform (including the ROC) of the following DT signal:
$ x[n]= n^2 \left( u[n+3]- u[n-1] \right) $
(Write enough intermediate steps to fully justify your answer.)
You will receive feedback from your instructor and TA directly on this page. Other students are welcome to comment/discuss/point out mistakes/ask questions too!
Answer 1
$ x[n] = n^2 (u[n+2]-u[n-1]) $.
$ X(z) = \sum_{n=-\infty}^{+\infty} x[n] z^{-n} $
$ = \sum_{n=-3}^{0} n^2 z^{-n} $
$ = 9 z^3 + 4 z^2 + z $
$ = z^3 (9 + 4 z^(-1) + z^(-2)) $ Write it here.
Answer 3
Write it here.
Answer 4
Write it here.
