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Question 20319
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Principles of Communication: Amplitude Modulation MCQ

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Amplitude ModulationHardQuestion 20319

Question

A broadcasting station uses a 500 W carrier modulated 80% by audio. The efficiency η (fraction of total power in sidebands) is:
  1. A
    24.2%
    Correct
  2. B
    50%
  3. C
    17%
  4. D
    32%

Correct answer

24.2%

Explanation

Psb = μ²Pc/2 = 0.64×500/2 = 160 W. Pt = 500+160 = 660 W. η = 160/660 = 24.24% ≈ 24.2%. This poor efficiency motivates SSB transmission where 100% of power is in the sideband.

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