1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Z transform question.

  1. Dec 9, 2006 #1
    1. The problem statement, all variables and given/known data
    consider the difference equation
    where u(n) is the input and given by
    u(n)=0 n<0
    u(n)=0 n=3,4,5.......
    determine the output x(n)

    3. The attempt at a solution
    let A=0.3679 and B=0.3642
    i took z transform for both sides so it became.
    z^2 x(z)-z^2x(0)-zx(1)-A[zx(z)-zx(0)]+Ax(z)=A[zu(z)-zu(0)]+Bu(z)

    then what can i do?
    also how can i make use of u(1)=0.2142
    i am too confused and need help.
  2. jcsd
  3. Dec 9, 2006 #2
    To solve the problem, you need to specify some initial conditions. As it stands, it's unsolvable.
  4. Dec 9, 2006 #3
    this is the full question given to me to solve and i am sure it is complete.
  5. Dec 26, 2006 #4
    late reply ,, have you known the correct solution ?

    the key that the input is not a step function , u have to use the u(0) , u(1) ... etc to draw the input and find expression to it .
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook