Discrete Time Signals and Systems on Digital Signal Processing related Questions and Answers

Question :   An LTI system is said to be causal if and only if 1. Impulse response is non-zero for positive values of n 2. Impulse response is zero for positive values of n 3. Impulse response is non-zero for negative values of n 4. Impulse response is zero for negative values of n Answer :   4 - Impulse response is zero for negative values of n