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Question 20265
JEE Physics · Hard

Principles of Communication: Amplitude Modulation MCQ

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Amplitude ModulationHardQuestion 20265

Question

If μ₁ = 0.3 and μ₂ = 0.4 are modulation indices of two sinusoidal tones modulating the same AM carrier, the total modulation index is:
  1. A
    0.7
  2. B
    0.5
    Correct
  3. C
    0.12
  4. D
    0.25

Correct answer

0.5

Explanation

For multiple tones, μtotal = √(μ₁² + μ₂²) = √(0.09 + 0.16) = √0.25 = 0.5. This must be ≤ 1 to avoid over-modulation. Total sideband power = μtotal² × Pc / 2.

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