View source for HW2.E Xujun Huang ECE301Fall2008mboutin - Rhea

The system is not time invariant

Let time delay = t

then 

Xk[n]=&delta;[n-k] -> time delay -> system

equals to X(k+t)[n]=&delta;[n-(k+t)]->system

equals to X(k+t)[n]=&delta;[n-k-t]->system

equals to Y(k+t)[n]=<math>(k+t+1)^2</math> &delta;[n-(k+t+1)]

while 

Xk[n]=&delta;[n-k] -> system -> time delay 

equals to Yk[n]=<math>(k+1)^2</math> &delta;[n-(k+1)]->time delay