Question

What is the commutative property?

(a) x(n)*h(n)=h(n)*x(n)

(b) x(n)+h(n)=h(n)+x(n)

(c) x(n)**h(n)=h(n)**x(n)

(d) x(n)h(n)=h(n)x(n)

This question was posed to me at a job interview.

I'm obligated to ask this question of Discrete Time Convolution topic in chapter Time-Domain Analysis of CT Systems of Signals and Systems

Answer 1

Right answer is (a) x(n)*h(n)=h(n)*x(n)

For explanation: The commutative property is x(n)*h(n)=h(n)*x(n), where x(n) is the input and h(n) is the impulse response of the ∂(n) input of an LTI system.

∑x[k]h[n-k], when we change the variables to n-k to k-n makes it equal to LHS and RHS.