Exam Questions Papers - Engineering

Q1:

If x1[n] x1(z) with ROC = R1 and x2[n] x2(z) with ROC = R2 then ROC for x1[n] + x2[n] will be __________ (where Ri → Region of convergence and x1[n] and x2[n] are causal).

A R1 ∩ R2

B R1 ∪ R2

C (R1 ∪ R2) ∩ (R1)

D (R1 ∩ R2) ∪ (R1)

ANS:A - R1 ∩ R2

R1 ∩ R2, Suppose R1 for x1(n) be Then ROC for x1(n) + x2(n) R1 ∩ R2 (R1 < R2) Then ROC for x1(n) + x2(n) R1 ∩ R2(R1 < R2)