Question

What is a circular or cyclic convolution?

(a) Convolution of a periodic and continuous time function

(b) Convolution of a periodic and discrete time function

(c) Superposition of periodic and periodic function

(d) Summation of continuous time and a convolution of a periodic function convolution

This question was addressed to me in an internship interview.

This interesting question is from Continuous Time Convolution in portion Time-Domain Analysis of CT Systems of Signals and Systems

Answer 1

Correct option is (d) Summation of continuous time and a convolution of a periodic function convolution

The explanation: The circular convolution is done of two aperiodic functions (i.e. Schwartz functions) happens when one of them is convolved in the normal way with a periodic summation of the other given function.

(Xn*h)[n]=∑h[m].xn[n-m], for discrete sequences n.