Question

A discrete-time system is causal if it

• A. Depends on future inputs
• B. Depends only on present and past inputs
• C. Depends on linearity
• D. Is stable

Hint:

A system is causal if \[ \boxed{ y[n]\ \text{depends only on}\ x[n],\,x[n-1],\,x[n-2],\ldots } \] and never on future inputs.

Answer 1

The Correct Option is B

Step 1: Recall the definition of causality. A causal system produces its output using only the current input and previous input values.

Step 2: Identify the correct statement. A causal system never depends on future input values. Therefore, \[ \boxed{\text{Depends only on present and past inputs}} \] is the correct answer. Hence, \[ \boxed{(B)} \] is the correct answer.