Question

Is the function y[n] = x[n-1] – x[n-56] causal?

(a) The system is non causal

(b) The system is causal

(c) Both causal and non causal

(d) None of the mentioned

This question was posed to me by my college director while I was bunking the class.

My enquiry is from Discrete Time Signals topic in chapter Signals and Systems Basics of Signals and Systems

Answer 1

The correct option is (b) The system is causal

Easiest explanation: As the value of the function depends solely on the value of the input at a time presently and/or in the past, it is a causal system.