JEE Main201910 Apr 2019Morning ShiftPhysicsCommunication SystemActual
A message signal of frequency 100 M H z and peak voltage 100 V is used execute amplitude modulation on a carrier wave of frequency 300 G H z and peak voltage 400 V . The modulation index and difference between the two side band frequencies are:
Options
- A4 ; 2 × 10 8 H z
- B0.25 ; 2 × 10 8 H z
- C4 ; 1 × 10 8 H z
- D0.25 ; 1 × 10 8 H z
Correct answer
B. 0.25 ; 2 × 10 8 H z
Step-by-step solution
Modulating index is given by, μ = A m A e = 100 V 400 V = 0.25 The difference between the maximum frequency of modulated wave and the minimum frequency of modulated wave is given by Δ f = f m a x - f m i n = f c + f m - f c - f m = 2 f m = 2 ( 100 M H z ) = 2 × 10 8 H z