The following diagrams represent systems with poles (indicated by x’s) but no zeros. The scale for each diagram is indicated by the circle, which has unit radius.
Which of X1(z) through X4(z) could represent a system with the following unit sample response?
1
X1(z) and X3(z)
2
X1(z) and X2(z)
3
X4(z)
4
None