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Question 20284
JEE Physics · Hard

Principles of Communication: Digital Communication MCQ

Solve this quality-checked JEE multiple-choice question, then review the correct answer and explanation.

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Digital CommunicationHardQuestion 20284

Question

OFDM (Orthogonal Frequency Division Multiplexing) is used in 4G LTE and Wi-Fi because it:
  1. A
    Requires only one carrier frequency
  2. B
    Splits data across many narrow sub-carriers, handling multipath efficiently
    Correct
  3. C
    Uses pulse modulation without a carrier
  4. D
    Avoids the need for a receiver

Correct answer

Splits data across many narrow sub-carriers, handling multipath efficiently

Explanation

OFDM uses hundreds/thousands of orthogonal narrow-band sub-carriers. Each sub-carrier is narrow enough to experience flat fading. A cyclic prefix eliminates inter-symbol interference from multipath. 4G LTE uses 1200 sub-carriers at 15 kHz spacing in a 20 MHz channel.

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