Question

An audio signal υ_m = 20sin2π(1500t) amplitude modulates a carrier υ_c =80 sin 2π (100,000t). The value of percent modulation is ________.

Answer 1

Correct answer is 25  

\(v_m = 20 sin [100\pi t+{\pi\over4}] \)

\(:v_c = 80 sin [10^4\pi t+{\pi\over6}] \)

we know that, modulation index =\(A_m\over A_c\) 

from given equations, A_m = 20 and A_c = 80 

percentage modulation index =\({A_m\over A_c}\times 100\) 

= \(20\over80\) × 100 = 25% 

The value of percentage modulation index is =25