(New page: ==The z-Transform== The z transform is a discrete time counterpart of Laplace transform. The Laplace transform is used on continuous signal while z transform is used for the discrete signa...) |
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<math>X(Z) = \sum_{n=-\infty}^{\infty}x[n]z^{-n}</math> | <math>X(Z) = \sum_{n=-\infty}^{\infty}x[n]z^{-n}</math> | ||
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| + | ==Region of Convergence(ROC)== | ||
| + | '''''property 1:-''''' The ROC of X(z) consists of a ring in the z-plane centered about the origin. | ||
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| + | '''''Property 2:-''''' The ROC does not contain any poles. | ||
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| + | '''''Property 3:-''''' If x[n] is of finite duration, then ROC is the entire z-plane, except possibly z=0 and/or <math>z=\infty</math> | ||
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| + | '''''Property 4:-''''' If x[n] is a right sided sequence and if the circle |z|=<math>r_0</math> is in the ROC then all finite values of z for which |z|><math>r_0</math> will also be in the ROC. | ||
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| + | '''''Property 5:-''''' If x[n] is a left sided sequence and if the circle |z|=<math>r_0</math> is in the ROC, then all vaues of z for which 0<|z|<<math>r_0</math> will also be in the ROC. | ||
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| + | '''''Property 6:-''''' If x[n] is two sided and if the circle |z|=<math>r_0</math> is in the ROC, then the ROC will consist of a ring in the z-plane that includes the circle |z|=<math>r_0</math>. | ||
Revision as of 14:18, 3 December 2008
The z-Transform
The z transform is a discrete time counterpart of Laplace transform. The Laplace transform is used on continuous signal while z transform is used for the discrete signal.
The z- transform of a general discrete signal x[n] is defined as
$ X(Z) = \sum_{n=-\infty}^{\infty}x[n]z^{-n} $
Region of Convergence(ROC)
property 1:- The ROC of X(z) consists of a ring in the z-plane centered about the origin.
Property 2:- The ROC does not contain any poles.
Property 3:- If x[n] is of finite duration, then ROC is the entire z-plane, except possibly z=0 and/or $ z=\infty $
Property 4:- If x[n] is a right sided sequence and if the circle |z|=$ r_0 $ is in the ROC then all finite values of z for which |z|>$ r_0 $ will also be in the ROC.
Property 5:- If x[n] is a left sided sequence and if the circle |z|=$ r_0 $ is in the ROC, then all vaues of z for which 0<|z|<$ r_0 $ will also be in the ROC.
Property 6:- If x[n] is two sided and if the circle |z|=$ r_0 $ is in the ROC, then the ROC will consist of a ring in the z-plane that includes the circle |z|=$ r_0 $.
