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I'm assuming <math>n\,</math> is the variable I will be applying the time shift to. I looked at some other peoples work and although they all thought <math>k\,</math> was the time variable, I think <math>k\,</math> is just the time step moving the function forward relative to some time position <math>n\,</math>. In other words , <math>k=2\,</math> doesn't mean time = 2 sec, it just means 2 time steps ahead of time <math>n\,</math>. Another reason I chose <math>n\,</math> to be the time variable is because when you discussed the sifting property in class you sifted by <math>n_0\,</math>, not <math>k\,</math>. | I'm assuming <math>n\,</math> is the variable I will be applying the time shift to. I looked at some other peoples work and although they all thought <math>k\,</math> was the time variable, I think <math>k\,</math> is just the time step moving the function forward relative to some time position <math>n\,</math>. In other words , <math>k=2\,</math> doesn't mean time = 2 sec, it just means 2 time steps ahead of time <math>n\,</math>. Another reason I chose <math>n\,</math> to be the time variable is because when you discussed the sifting property in class you sifted by <math>n_0\,</math>, not <math>k\,</math>. | ||
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<math> X_k[n]=Y_k[n] \,</math> | <math> X_k[n]=Y_k[n] \,</math> | ||
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where | where | ||
Revision as of 08:29, 11 September 2008
Question 6a
I'm assuming $ n\, $ is the variable I will be applying the time shift to. I looked at some other peoples work and although they all thought $ k\, $ was the time variable, I think $ k\, $ is just the time step moving the function forward relative to some time position $ n\, $. In other words , $ k=2\, $ doesn't mean time = 2 sec, it just means 2 time steps ahead of time $ n\, $. Another reason I chose $ n\, $ to be the time variable is because when you discussed the sifting property in class you sifted by $ n_0\, $, not $ k\, $.
$ X_k[n]=Y_k[n] \, $
where
$ X_k[n]=\delta[n-k]\, $
and
$ Y_k[n]=(k+1)^2 \delta[n-(k+1)] \, $
Consider the value of the system at when time = 0s
Under this assumption the following system cannot possibly be time invariant because of the $ (k+1)^2 $ term.
