Question

For a periodic signal () = 30 sin 1000 + 10 cos 3000 + 6 sin(5000 +  4), the fundamental frequency in rad/s is __________

(a) 1000

(b) 3000

(c) 5000

(d) 15000

The question was posed to me in unit test.

My question is taken from Common Fourier Transforms topic in division Fourier Transform of Signals and Systems

Answer 1

Correct answer is (a) 1000

For explanation I would say: First term has w1 = 1000 rad/s

Second term has w2 = 3000 rad/s

Third term has w3 = 500 rad/s

Now, w1 is the fundamental frequency, w2 is the third harmonic and w3 is the 5th harmonic. So, fundamental frequency = 1000 rad/s.