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The following statements are given below—
(i) y[n] = 3x[n – 2] + 8x[n + 2]
(ii) y[n] = x[n – 1] + ax[n – 2]
(iii) y[n] = x[– n] is non-causal
The correct statements is/are—
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- (i) only
- (ii) and (iii) only
- (i), (ii) and (iii) all
- (iii) only
Correct Option: B
(i) y(n)= 3x(n – 2) + 8x(n + 2)
Here, y(n) is determined the past input samples value 3x(n – 2) and future input value 8x(n – 2) and hence the system is non-causal.
(ii) y(n) = x(n – 1) + ax(n – 2)
Here, y(n) is determined the past input samples value both for term x(n – 1) and ax(n – 2). Hence, the system is causal.
(iii) y(n) = x(– n)
Here, the input sample value is located on the negative time axis and for any negative value output depends on the future value. Hence, the system is non-causal.
Hence, alternative (B) is the correct choice.
