If the z-transform of x[n] is X(z)

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SUMMARY

The z-transform of x[n+1] can be derived from the z-transform of x[n], denoted as X(z), using the shift theorem. Specifically, if the z-transform of x[n] is X(z), then the z-transform of x[n+1] is X(z)z. The discussion emphasizes the importance of understanding the unilateral z-transform, particularly in the context of causal systems, which parallels the Laplace transform used in LTI circuit analysis. The participants clarify the procedure for deriving the z-transform of shifted sequences, highlighting the need for careful manipulation of summation indices.

PREREQUISITES
  • Understanding of z-transforms and their properties
  • Familiarity with the shift theorem in signal processing
  • Knowledge of unilateral z-transforms for causal systems
  • Basic concepts of linear time-invariant (LTI) systems
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  • Study the derivation of the z-transform for shifted sequences
  • Learn about the relationship between z-transforms and Laplace transforms
  • Explore applications of z-transforms in digital signal processing
  • Investigate the implications of unilateral vs bilateral z-transforms
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Students and professionals in electrical engineering, particularly those focused on signal processing, control systems, and anyone working with z-transforms in digital systems.

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If the z-transform of x[n] is X(z), then what is the z-transform of x[n+1] in terms of X(z) ?
 
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symsane said:
If the z-transform of x[n] is X(z), then what is the z-transform of x[n+1] in terms of X(z) ?
There is a shift theorem, similar to the other kinds of reciprocal transforms. To prove it, just change n to n' in the sum, replace n' by n+1, and then shift the sum back to n.
 


OK I know this Shift Theorem, but I have a problem with it. If the z-transform of x[n] is X(z), I can solve the z-transform of x[n-1] in terms of X(z) and what I found is X(z)z-1+x[-1]. However what is the solution if I want to solve the z-transform of x[n+1] in terms of X(z) ? Or in this case, I can ask this question: How can I solve the z-transform of x[n] if I know the z-transform x[n-1] in terms of X(z) ( As I found x[n-1] = X(z)z-1+x[-1])?
 


I searched the net and I found left shift of z-transform. In this question it is very useful.When we applied this definition we acquire the solution.
 


symsane said:
If the z-transform of x[n] is X(z), I can solve the z-transform of x[n-1] in terms of X(z) and what I found is X(z)z-1+x[-1].
OK, so you are using the UNILATERAL transform (i.e. for causal systems). So, you should see some similarities to the Laplace transform. If you've studied transient response of LTI circuit, the Laplace transform is what you (probably) use there.



symsane said:
... I want to solve the z-transform of x[n+1] in terms of X(z) ?
If you know how to prove the result that you have above for xn-1, then you should be able to do this. Did you read my previous post? Are you having trouble arranging terms in the summation?

EDIT: Sorry, I had a typo in a previous post. I will restate the procedure:

Change n to n' in the sum. Replace n' with n-1. Of course, if you do what I said in the previous post, that will not give you a wrong answer, but it will not help either.
 
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