Question

How is the period of the sum signal computed as?

(a) T*n

(b) T*T

(c) T*N+M

(d) T *(n+m)

I have been asked this question in an internship interview.

This question is from Periodic Signals in section Fourier Series of Signals and Systems

Answer 1

Right choice is (a) T*n

Easiest explanation: If a signal is periodic then we have to convert each of the periods to the ratio of integers. We have to take the ratio of greatest common divisor(gcd) from the numerator to the gcd of denominator. The LCM of the denominators of the resulting ratios is the value of n the period of the sum signal is T*n.