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Question 20322
JEE Physics · Hard

Principles of Communication: Digital Communication MCQ

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Digital CommunicationHardQuestion 20322

Question

The bit error rate (BER) of BPSK in AWGN is given by Q(√(2Eb/N0)). If Eb/N0 = 9 dB (≈ 7.94), BER is approximately:
  1. A
    10⁻²
  2. B
    10⁻³
  3. C
    10⁻⁴
  4. D
    10⁻⁵
    Correct

Correct answer

10⁻⁵

Explanation

At Eb/N0 = 9 dB: Q(√(2×7.94)) = Q(√15.88) = Q(3.985) ≈ Q(4) ≈ 3.17×10⁻⁵ ≈ 10⁻⁵. This is a standard design target for voice (10⁻³) is acceptable; data (10⁻⁶) needed before FEC. After turbo/LDPC coding, 10⁻⁵ uncoded BER becomes effectively zero.

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