An LTI system is said to be causal if and only if
A. Impulse response is non-zero for positive values of n
B. Impulse response is zero for positive values of n
C. Impulse response is non-zero for negative values of n
D. Impulse response is zero for negative values of n
Answer:A
An LTI system is said to be causal if and only if
A. Impulse response is non-zero for positive values of n B. Impulse response is zero for positive values of n C. Impulse response is non-zero for negative values of n D. Impulse response is zero for negative values of n
Explanation: Let us consider a LTI system having an output at time n=n0given by the convolution formula