1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Z transform - simple question

  1. Oct 15, 2006 #1
    hi guys.
    Just want to clarify something with the z transform and convergence.

    Do you guys aggree with this.

    If an expression does not converge you CAN STILL find the z transform (using power series) for the system HOWEVER this will not be the closed form z transform.

    just wondering - because in any z transform table you are given a region of convergence - but this is for closed form z transforms.
    I suppose all systems are stable if they converge.

  2. jcsd
  3. Oct 15, 2006 #2
    sorry - i think my last statement may be a bit to generalized:"I suppose all systems are stable if they converge."

    you can get a system that converges but is not necessarily stable. E.g.
    z/(z-a) where region of convergence is defined by, mod |z| > |a|

    but a can be bigger then unity (which wil make the system unstable) but the system will still converge as long as z > a. Do you guys aggree?
    makes sense beacuse i just read somewhere that for a system to be stable , the region of convergence must include the unit circle.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Z transform - simple question
  1. Z transform (Replies: 10)

  2. Z transforms (Replies: 1)